Understanding How COVID-19 Vaccines Work | CDC

How Corona Vaccine Works (with video) Vaccine Mechanism of Action

How Corona Vaccine Works (with video) Vaccine Mechanism of Action

The COVID-19 vaccine works similarly to other vaccines your child has had. Germs such as SARS-CoV-2, the virus that causes COVID-19. But how do the different types of COVID-19 vaccines work? Each COVID-19 vaccine causes the immune system to create antibodies to fight COVID-19. COVID-19 vaccine page. Through the COVAX Global Vaccine Facility and other mechanisms, WHO and partners are working with How do vaccines work?

Opinion: How Corona Vaccine Works (with video) Vaccine Mechanism of Action

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COVID-19 vaccine

Vaccine designed to provide acquired immunity against SARS-CoV-2

How COVID-19 vaccines work.The video shows the process of vaccination, from injection with RNA or viral vector vaccines, to uptake and translation, and on to immune system stimulation and effect.
Map showing share of population fully vaccinated against COVID-19 relative to a country's total population
Map of countries by approval status

  Approved for general use, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, mass vaccination underway

  EUA (or equivalent) granted, mass vaccination underway

  EUA granted, limited vaccination

  Approved for general use, mass vaccination planned

  EUA granted, mass vaccination planned

  EUA pending

  No data available

COVID-19 vaccine doses administered by continent as of Oct 11, 2021. For vaccines that require multiple doses, each individual dose is counted. As the same person may receive more than one dose, the number of doses can be higher than the number of people in the population.

A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus that causes coronavirus disease 2019 (COVID‑19). Prior to the COVID‑19 pandemic, an established body of knowledge existed about the structure and function of coronaviruses causing diseases like severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). This knowledge accelerated the development of various vaccine platforms during early 2020.[1] The initial focus of SARS-CoV-2 vaccines was on preventing symptomatic, often severe illness.[2] On 10 January 2020, the SARS-CoV-2 genetic sequence data was shared through GISAID, and by 19 March, the global pharmaceutical industry announced a major commitment to address COVID-19.[3] The COVID‑19 vaccines are widely credited for their role in reducing the spread, severity, and death caused by COVID-19.[4]

Many countries have implemented phased distribution plans that prioritize those at highest risk of complications, such as the elderly, and those at high risk of exposure and transmission, such as healthcare workers.[5] Single dose interim use is under consideration to extend vaccination to as many people as possible until vaccine availability improves.[6][7][8][9]

As of 18 November 2021[update], 7.62 billion doses of COVID‑19 vaccines have been administered worldwide based on official reports from national public health agencies.[10]AstraZeneca anticipates producing 3 billion doses in 2021, Pfizer–BioNTech 2.5 billion doses,[11] and Sputnik V, Sinopharm, Sinovac, and Janssen 1 billion doses each. Moderna targets producing 600 million doses and Convidecia 500 million doses in 2021.[12][13] By December 2020, more than 10 billion vaccine doses had been preordered by countries,[14] with about half of the doses purchased by high-income countries comprising 14% of the world's population.[15]

Background

A US airmanreceiving a COVID-19 vaccine, December 2020

Prior to COVID‑19, a vaccine for an infectious disease had never been produced in less than several years – and no vaccine existed for preventing a coronavirus infection in humans.[16] However, vaccines have been produced against several animal diseases caused by coronaviruses, including (as of 2003) infectious bronchitis virus in birds, canine coronavirus, and feline coronavirus.[17] Previous projects to develop vaccines for viruses in the family Coronaviridae that affect humans have been aimed at severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Vaccines against SARS[18] and MERS[19] have been tested in non-human animals.

According to studies published in 2005 and 2006, the identification and development of novel vaccines and medicines to treat SARS was a priority for governments and public health agencies around the world at that time.[20][21][22] There is no cure or protective vaccine proven to be safe and effective against SARS in humans.[23][24] There is also no proven vaccine against MERS.[25] When MERS became prevalent, it was believed that existing SARS research might provide a useful template for developing vaccines and therapeutics against a MERS-CoV infection.[23][26] As of March 2020, there was one (DNA-based) MERS vaccine which completed Phase I clinical trials in humans,[27] and three others in progress, all being viral-vectored vaccines: two adenoviral-vectored (ChAdOx1-MERS, BVRS-GamVac) and one MVA-vectored (MVA-MERS-S).[28]

Vaccines that use an inactive or weakened virus that has been grown in eggs typically take more than a decade to develop.[29][30] In contrast, mRNA is a molecule that can be made quickly, and research on mRNA to fight diseases was begun decades before the COVID-19 pandemic by scientists such as Drew Weissman and Katalin Karikó, who tested on mice, How Corona Vaccine Works (with video) Vaccine Mechanism of Action. Moderna began human testing of an mRNA vaccine in 2015.[29]Viral vector vaccines were also developed for the COVID-19 pandemic after the technology was previously cleared for Ebola.[29]

As multiple COVID-19 vaccines have been authorized or licensed for use, real-world vaccine effectiveness (RWE) is now being assessed using case control and observational studies.[31] A study is investigating the long-lasting protection against SARS-CoV-2 provided by the mRNA vaccines.[32] On 10 August 2021, a study showed that the full vaccination coverage rate is correlated inversely to the SARS-CoV-2 delta variant mutation frequency in 16 countries (R-squared=0.878).[33]

Formulation

As of September 2020[update], eleven of the vaccine candidates in clinical development use adjuvants to enhance immunogenicity.[34] An immunological adjuvant is a substance formulated with a vaccine to elevate the immune response to an antigen, such as the COVID‑19 virus or influenza virus.[35] Specifically, an adjuvant may be used in formulating a COVID‑19 vaccine candidate to boost its immunogenicity and efficacy to reduce or prevent COVID‑19 infection in vaccinated individuals.[35][36] Adjuvants used in COVID‑19 vaccine formulation may be particularly effective for technologies using the inactivated COVID‑19 virus and recombinant protein-based or vector-based vaccines.[36]Aluminum salts, known as "alum", were the first adjuvant used for licensed vaccines, and are the adjuvant of choice in some 80% of adjuvanted vaccines.[36] The alum adjuvant initiates diverse molecular and cellular mechanisms to enhance immunogenicity, including release of proinflammatory cytokines.[35][36]

Sequencing

In November 2021, the full nucleotide sequences of the AstraZeneca and Pfizer/BioNTech vaccines were released by the UK Medicines and Healthcare Products Regulatory Agency, in response to a Freedom of Information request.[37][38]

Clinical research

Main article: COVID-19 vaccine clinical research

COVID-19 vaccine clinical research uses clinical research to establish the characteristics of COVID-19 vaccines. These characteristics include efficacy, effectiveness and safety. 24 vaccines are authorized for use by national governments, including six approved for emergency or full use by at least one WHO-recognised stringent regulatory authority; while five are in Phase IV. 204 vaccines are undergoing clinical trials that have yet to be authorized. Nine clinical trials consider heterologous vaccination courses.

Twenty vaccines are authorized by at least one national regulatory How Corona Vaccine Works (with video) Vaccine Mechanism of Action public How Corona Vaccine Works (with video) Vaccine Mechanism of Action one DNA vaccine(ZyCoV-D) two RNA vaccines(Pfizer–BioNTechand Moderna), ten conventional inactivated vaccines(BBIBP-CorV, Chinese Academy of Medical Sciences, CoronaVac, Covaxin, CoviVac, COVIran Barekat, FAKHRAVAC, Minhai-Kangtai, QazVac, and WIBP-CorV), five viral vector vaccines(Sputnik Light, Sputnik V, Oxford–AstraZeneca, Convidecia, and Janssen), and six subunit vaccines(Abdala, COVAX-19, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, EpiVacCorona, MVC-COV1901, Soberana 02, and ZF2001).[39][40]As of July 2021, 330 vaccine candidates were in various stages of development, with 102 in clinical research, including 30 in Phase I trials, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, 30 in Phase I–II trials, 25 in Phase III trials, and 8 in Phase IV development.[39]

Post-vaccination complications

Main article: Embolic and thrombotic events after COVID-19 vaccination

Vaccine types

Vaccine platforms being employed for SARS-CoV-2. Whole virus vaccines include both attenuatedand inactivatedforms of the virus. Protein and peptidesubunitvaccines are usually combined with an adjuvantin order to enhance immunogenicity. The main emphasis in SARS-CoV-2 vaccine development has been on using the whole spike proteinin its trimeric form, or components of it, such as the RBDregion. Multiple non-replicating viral vector vaccineshave been developed, particularly focused on adenovirus, while there has been less emphasis on the replicating viral vector constructs.[53]

At least nine different technology platforms are under research and development to create an effective vaccine against COVID‑19.[34][54] Most of the platforms of vaccine candidates in clinical trials are focused on the coronavirus spike protein (S protein) and its variants as the primary antigen of COVID‑19 infection,[34] since the S protein triggers strong B-cell and T-cell immune responses.[55][56] However, other coronavirus proteins are also being investigated for vaccine development, like the nucleocapsid, because they also induce a robust T-cell response and their genes are more conserved and recombine less frequently (compared to Spike).[56][57][58]

Platforms being developed in 2020 involved nucleic acid technologies (nucleoside-modified messenger RNA and DNA), non-replicating viral vectors, peptides, recombinant proteins, live attenuated viruses, and inactivated viruses.[16][34][59][60]

Many vaccine technologies being developed for COVID‑19 are not like vaccines already in use to prevent influenza, but rather are using "next-generation" strategies for precise targeting of COVID‑19 infection mechanisms.[34][59][60] Several of the synthetic vaccines use a 2P mutation to lock the spike protein into its prefusion configuration, stimulating an adaptive immune response to the virus before it attaches to a human cell.[61] How Corona Vaccine Works (with video) Vaccine Mechanism of Action platforms in development may improve flexibility for antigen manipulation, and effectiveness for targeting mechanisms of COVID‑19 infection in susceptible population subgroups, such as healthcare workers, the elderly, children, pregnant women, and people with weakened immune systems.[34][59]

mRNA vaccines

Further information: mRNA vaccine

Several COVID-19 vaccines, including the Pfizer–BioNTech and Moderna vaccines, have been developed to use RNA to stimulate an immune response. When introduced into human tissue, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, the vaccine contains either self-replicating RNA or messenger RNA (mRNA), which both cause cells to express the SARS-CoV-2 spike protein. This teaches the body how to identify and destroy the corresponding pathogen. RNA vaccines often, but not always, use nucleoside-modified messenger RNA. The delivery of mRNA is achieved by a coformulation of the molecule into lipid nanoparticles which protect the RNA strands and help their absorption into the cells.[62][63][64][65]

RNA vaccines were the first COVID‑19 vaccines to be authorized in the United Kingdom, the United States and the European Union.[66][67] Authorized vaccines of this type are the Pfizer–BioNTech[68][69][70] and Moderna vaccines.[71][72] The CVnCoV RNA vaccine from CureVac failed in clinical trails.[73]

Severe allergic reactions are rare. In December 2020, 1,893,360 first doses of Pfizer–BioNTech COVID‑19 vaccine administration resulted in 175 cases of severe allergic reaction, of which 21 were anaphylaxis.[74] For 4,041,396 Moderna COVID‑19 vaccine dose administrations in December 2020 and January 2021, only ten cases of anaphylaxis were reported.[74]Lipid nanoparticles (LNPs) were most likely responsible for the allergic reactions.[74]

Adenovirus vector vaccines

These vaccines are examples of non-replicating viral vector vaccines, using an adenovirus shell containing DNA that encodes a SARS‑CoV‑2 protein.[75][76] The viral vector-based vaccines against COVID‑19 are non-replicating, meaning that they do not make new virus particles, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, but rather produce only the antigen which How Corona Vaccine Works (with video) Vaccine Mechanism of Action a systemic immune response.[75]

Authorized vaccines of this type are the Oxford–AstraZeneca COVID-19 vaccine,[77][78][79] the Sputnik V COVID-19 vaccine,[80]Convidecia, and the Janssen COVID-19 vaccine.[81][82]

Convidecia and the Janssen COVID-19 vaccine are both one-shot vaccines which offer less complicated logistics and can be stored under ordinary refrigeration for several months.[83][84]

Sputnik V uses Ad26 for its first dose, which is the same as How Corona Vaccine Works (with video) Vaccine Mechanism of Action only dose, and Ad5 for the second dose, which is the same as Convidecia's only dose.[85]

On 11 August 2021, the developers of Sputnik V proposed, in view of the Delta case surge that Pfizer test the Ad26 component (termed its ‘Light’ version)[86] as a booster shot:

Delta cases surge in US & Israel shows mRNA vaccines need a heterogeneous booster to strengthen & prolong immune response. #SputnikV pioneered mix&match approach, combo trials & showed 83.1% efficacy vs Delta. Today RDIF offers Pfizer to start trial with Sputnik Light as booster.[87]

Inactivated virus vaccines

Inactivated vaccines consist of virus particles that have been grown in culture and then are killed using a method such as heat or formaldehyde to lose disease producing capacity, while still stimulating an immune response.[88]

Authorized vaccines of this type are the Chinese CoronaVac,[89][90][91]BBIBP-CorV,[92] and WIBP-CorV; the Indian Covaxin; later this year the Russian CoviVac;[93] the Kazakhstani vaccine QazVac;[94] and the Iranian COVIran Barekat.[95] Vaccines in clinical trials include the Valneva COVID-19 vaccine.[96][unreliable source?][97]

Subunit vaccines

Subunit vaccines present one or more antigens without introducing whole pathogen particles. The antigens involved are often protein subunits, but can be any molecule that is a fragment of the pathogen.[98]

The three authorized vaccines of this type are the peptide vaccineEpiVacCorona,[99]ZF2001,[54] and MVC-COV1901.[100] Vaccines with pending authorizations include the Novavax COVID-19 vaccine,[101]Soberana 02 (a conjugate vaccine), and the Sanofi–GSK vaccine.

The V451 vaccine was previously in clinical trials, which were terminated because it was found that the vaccine may potentially cause incorrect results for subsequent HIV testing.[102][103]

Intranasal

Intranasal vaccines target mucosal immunity in the nasal mucosa which is a portal for viral entrance to the body.[104][105] These vaccines are designed to stimulate nasal immune factors, such as IgA.[104] In addition to inhibiting the virus, nasal vaccines provide ease of administration because no needles (and the accompanying needle phobia) are involved.[105][106] Nasal vaccines have been approved for other infections, such as influenza.[105][106] As of 2021, only one nasal vaccine, Flumist (USA); Fluenz Tetra (European Union), had been authorized in the United States and Europe for use as an influenza vaccine.[106][107][clarification needed]

Other types

Additional types of vaccines that are in clinical trials include virus-like particle vaccines, multiple DNA plasmid vaccines,[108][109][110][111][112][113] at least two lentivirus vector vaccines,[114][115] a conjugate vaccine, and a vesicular stomatitis virus displaying the SARS‑CoV‑2 spike protein.[116]

Scientists investigated whether existing vaccines for unrelated conditions could prime the immune system and lessen the severity of COVID‑19 infection.[117] There is experimental evidence that the BCG vaccine for tuberculosis has non-specific effects on the immune system, but no evidence that this vaccine is effective against COVID‑19.[118]

Planning and development

Main article: History of COVID-19 vaccine development

Since January 2020, vaccine development has been expedited via unprecedented collaboration in the multinational pharmaceutical industry and between governments.[34]

Multiple steps along the entire development path are evaluated, including:[16][119]

  • the level of acceptable toxicity of the vaccine (its safety),
  • targeting vulnerable populations,
  • the need for vaccine efficacy breakthroughs,
  • the duration of vaccination protection,
  • special delivery systems (such as oral or nasal, rather than by injection),
  • dose regimen,
  • stability and storage characteristics,
  • emergency use authorization before formal licensing,
  • optimal manufacturing for scaling to billions of doses, and
  • dissemination of the licensed vaccine.

Challenges

There have been several unique challenges with COVID‑19 vaccine development.

The urgency to create a vaccine for COVID‑19 led to compressed schedules that shortened the standard vaccine development timeline, in some cases combining clinical trial steps over months, a process typically conducted sequentially over several years.[120] Public health programs have been described as in "[a] race to vaccinate individuals" with the early wave vaccines.[121]

Timelines for conducting clinical research – normally a sequential process requiring years – are being compressed into safety, efficacy, and dosing trials running simultaneously over months, potentially compromising safety assurance.[120][122] As an example, Chinese vaccine developers and the government Chinese Center for Disease Control and Prevention began their efforts in January 2020,[123] and by March were pursuing numerous candidates on short timelines, with the goal to showcase Chinese technology strengths over those of the United States, and to reassure the Chinese people about the quality of vaccines produced in China.[120][124]

The rapid development and urgency of producing a vaccine for the COVID‑19 pandemic was expected to increase the risks and failure rate of delivering a safe, effective vaccine.[59][60][125] Additionally, research at universities is obstructed by physical distancing and closing of laboratories.[126][127]

Vaccines must progress through several phases of clinical trials to test for safety, immunogenicity, effectiveness, dose levels and adverse effects of the candidate vaccine.[128][129] Vaccine developers have to invest resources internationally to find enough participants for Phase II–III clinical trials when the virus has proved to be a "moving target" of changing transmission rates across and within countries, forcing companies to compete for trial participants.[130] Clinical trial organizers also may encounter people unwilling to be vaccinated due to vaccine hesitancy[131] or disbelief in the science of the vaccine technology and its ability to prevent infection.[132] As new vaccines are developed during the COVID‑19 pandemic, licensure of COVID‑19 vaccine candidates requires submission of a full dossier of information on development and manufacturing quality.[133][134][135]

Organizations

Internationally, the Access to COVID-19 Tools Accelerator is a G20 and World Health Organization (WHO) initiative announced in April 2020.[136][137] It is a cross-discipline support structure to enable partners to share resources and knowledge. It comprises four pillars, each managed by two to three collaborating partners: Vaccines (also called "COVAX"), Diagnostics, Therapeutics, and Health Systems Connector.[138] The WHO's April 2020 "R&D Blueprint (for the) novel Coronavirus" documented a "large, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, international, multi-site, individually randomized controlled clinical trial" to allow "the concurrent evaluation of the benefits and risks of each promising candidate vaccine within 3–6 months of it being made available for the trial." The WHO vaccine coalition will prioritize which vaccines should go into Phase II and III clinical trials, and determine harmonized Phase III protocols for all vaccines achieving the pivotal trial stage.[139]

National governments have also been involved in vaccine development. Canada announced funding of 96 projects for development and production of vaccines at Canadian companies and universities with plans to establish a "vaccine bank" that could be used if another coronavirus How Corona Vaccine Works (with video) Vaccine Mechanism of Action occurs,[140] and to support clinical trials and develop manufacturing and supply chains for vaccines.[141]

China provided low-rate loans to one vaccine developer through its central bank, and "quickly made land available for the company" to build production plants.[122] Three Chinese vaccine companies and research institutes are supported by the government for financing research, conducting clinical trials, and manufacturing.[142]

Great Britain formed a COVID‑19 vaccine task force in April 2020 to stimulate local efforts for accelerated development of a vaccine through collaborations of industry, universities, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, and government agencies. It encompassed every phase of development from research to manufacturing.[143]

In the United States, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, the Biomedical Advanced Research and Development Authority (BARDA), a federal agency funding disease-fighting technology, announced investments to support American COVID‑19 vaccine development, and manufacture of the most promising candidates.[122][144] In May 2020, the government announced funding for a fast-track program called Operation Warp Speed.[145][146] By March 2021, BARDA had funded an estimated $19.3 billion in COVID-19 vaccine development.[147]

Large pharmaceutical companies with experience in making vaccines at scale, including Johnson & Johnson, AstraZeneca, and GlaxoSmithKline (GSK), formed alliances with biotechnology companies, governments, and universities to accelerate progression towards effective vaccines.[122][120]

History

COVID‑19 vaccine research samples in a NIAIDlab freezer (30 January 2020)

COVID-19's caused virus, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), was isolated in late 2019.[148] Its genetic sequence was published on 11 January 2020, triggering an urgent international response to prepare for an outbreak and hasten development of a preventive COVID-19 vaccine.[149][150][151] Since 2020, vaccine development has been expedited via unprecedented collaboration in the multinational pharmaceutical industry and between governments.[152] By June 2020, tens of billions of dollars were invested by corporations, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, governments, international health organizations, and university research groups to develop dozens of vaccine candidates and prepare for global vaccination programs to immunize against COVID‑19 infection.[150][153][154][155] According to the Coalition for Epidemic Preparedness Innovations (CEPI), the geographic distribution of COVID‑19 vaccine development shows North American entities to have about 40% of the activity, compared to 30% in Asia and Australia, 26% in Europe, and a few projects in South America and Africa.[149][152]

In February 2020, the World Health Organization (WHO) said it did not expect a vaccine against SARS‑CoV‑2 to become available in less than 18 months.[156] Virologist Paul Offit commented that, in hindsight, the How Corona Vaccine Works (with video) Vaccine Mechanism of Action of a safe and effective vaccine within 11 months was a remarkable feat.[157] The rapidly growing infection rate of COVID‑19 worldwide during 2020 stimulated international alliances and government efforts to urgently organize resources to make multiple vaccines on shortened timelines,[158] with four vaccine candidates entering human evaluation in March (see COVID-19 vaccine § Trial and authorization status).[149][159]

On 24 June 2020, China approved the CanSino vaccine for limited use in the military, and two inactivated virus vaccines for emergency use in high-risk occupations.[160] On 11 August 2020, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, Russia announced the approval of its Sputnik V vaccine for emergency use, though one month later only small amounts of the vaccine had been distributed for use outside of the phase 3 trial.[161]

The Pfizer–BioNTech partnership submitted an Emergency Use Authorization (EUA) request to the U.S. Food and Drug Administration (FDA) for the mRNA vaccine BNT162b2 (active ingredient tozinameran) on 20 November 2020.[162][163] On 2 December 2020, the United Kingdom's Medicines and Healthcare products Regulatory Agency (MHRA) gave temporary regulatory approval for the Pfizer–BioNTech vaccine,[164][165] becoming the first country to approve the vaccine and the first country in the Western world to approve the use of any COVID‑19 vaccine.[166][167][168] As of 21 December 2020, many countries and the European Union[169] had authorized or approved the Pfizer–BioNTech COVID‑19 vaccine. Bahrain and the United Arab Emirates granted emergency marketing authorization for BBIBP-CorV, manufactured by Sinopharm.[170][171] On 11 December 2020, the FDA granted an EUA for the Pfizer–BioNTech COVID‑19 vaccine.[172] A week later, they granted an EUA for mRNA-1273 (active ingredient elasomeran), the Moderna vaccine.[173][174][175][176]

On 31 March 2021, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, the Russian government announced that they had registered the first COVID‑19 vaccine for animals.[177]Named Carnivac-Cov, it is an inactivated vaccine for carnivorous animals, including pets, aimed at preventing mutations that occur during the interspecies transmission of SARS-CoV-2.[178]

In June 2021, a report revealed that the UB-612 vaccine, developed by the US-based COVAXX, was a venture initiated for profits by the Blackwater founder Erik Prince. In a series of text messages to Paul Behrends, the close associate recruited for the COVAXX project, Prince described the profit-making possibilities in selling the COVID‑19 vaccines. COVAXX provided no data from the clinical trials on safety or efficacy. The responsibility of creating distribution networks was assigned to an Abu Dhabi-based entity, which was mentioned as "Windward Capital" on the COVAXX letterhead but was actually Windward Holdings. The firm's sole shareholder, which handled "professional, scientific and technical activities", was Erik Prince. In March 2021, COVAXX raised $1.35 billion in a private placement.[179]

Effectiveness

This section is an excerpt from COVID-19 vaccine clinical research § Effectiveness.[edit]

As of August 2021, studies reported that the COVID-19 vaccines available in the United States are "highly protective against severe illness, hospitalization, and death due to COVID-19".[180] In comparison with fully vaccinated people, the CDC reported that unvaccinated people were 5 times more likely to be infected, 10 times more likely to be hospitalized, and 11 times more likely to die.[181][182]

Against the Delta variant, studies concluded that these vaccines provided 55 percent protection against infection, 80 percent against symptomatic infection, and at least 90 percent against hospitalization.[183][medical citation needed] The CDC similarly found that vaccines were 90 percent effective at preventing hospitalizations.[184]

Another study found that unvaccinated people were six times more likely to test positive, 37 times more likely to be hospitalized, and 67 times more likely to die, compared to those who had been vaccinated.[185]

CDC reported that vaccine effectiveness fell from 91% against Alphato 66% against Delta.[186]One expert stated that "those who are infected following vaccination are still not getting sick and not dying like was happening before vaccination."[187]By late August 2021 the Delta variant accounted for 99 percent of U.S. cases and was found to double the risk of severe illness and hospitalization for those not yet vaccinated.[188]

Adverse events

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This section needs expansion. You can help by adding to it. (July 2021)

Serious adverse events associated with receipt of new vaccines targeting COVID-19 are Ableton Live Key Archives - Malik Softs high interest to the public.[189] All vaccines that are administered via intramuscular injection, including COVID-19 vaccines, have side effects related to the mild trauma associated with the procedure and introduction of a foreign substance into the body.[190] These include soreness, redness, rash, and inflammation at the injection site. Other common side effects include fatigue, headache, myalgia (muscle pain), and arthralgia (joint pain) which generally resolve within a few days.[191] One less-frequent side How Corona Vaccine Works (with video) Vaccine Mechanism of Action (that generally occurs in less than 1 in 1,000 people) is hypersensitivity (allergy) to one or more of the vaccine's ingredients, which in some rare cases may cause anaphylaxis.[192][193][194][195] An increased risk of rare and potentially fatal thrombosis events have been associated in mainly younger female patients, following the administration of the Janssen (Johnson and Johnson)[196][197] and Oxford-AstraZenica COVID-19 vaccines.[197][198][199][200]

Society and culture

Distribution

Main article: Deployment of COVID-19 vaccines

Note about table to the right: Number and percentage of people who have received at least one dose of a COVID-19 vaccine (unless noted otherwise). May include vaccination of non-citizens, which can push totals beyond 100% of the local population. Table is updated daily by a bot.[note 1]

Location Vaccinated[b]%[c]
World[d]4,127,343,36152.4%
ChinaChina1,185,237,00082.1%
IndiaIndia758,251,60554.4%
European UnionEuropean Union312,056,83369.8%
United StatesUnited States[e]228,175,63867.8%
BrazilBrazil162,436,79175.9%
IndonesiaIndonesia132,006,37747.8%
JapanJapan99,404,56778.9%
PakistanPakistan78,654,48934.9%
MexicoMexico75,497,76258.0%
VietnamVietnam65,222,95366.4%
RussiaRussia62,594,26042.9%
GermanyGermany58,434,22969.7%
TurkeyTurkey55,939,33665.8%
IranIran55,576,53365.4%
BangladeshBangladesh52,526,91631.6%
FranceFrance51,582,54076.3%
United KingdomUnited Kingdom50,645,98174.2%
ItalyItaly[f]46,914,94377.7%
ThailandThailand45,700,03665.3%
South KoreaSouth Korea42,110,65282.1%
PhilippinesPhilippines42,093,48938.2%
SpainSpain38,177,68581.7%
ArgentinaArgentina35,938,52778.8%
ColombiaColombia33,470,56765.3%
CanadaCanada30,102,54579.1%
MalaysiaMalaysia25,599,17378.1%
How Corona Vaccine Works (with video) Vaccine Mechanism of Action Arabia" src="https://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/Flag_of_Saudi_Arabia.svg/23px-Flag_of_Saudi_Arabia.svg.png" width="23" height="15">Saudi Arabia24,463,68269.2%
MoroccoMorocco24,458,50665.5%
EgyptEgypt21,121,56420.3%
PeruPeru20,929,91762.7%
PolandPoland20,509,51654.3%
AustraliaAustralia19,684,79076.3%
TaiwanTaiwan17,961,33675.3%
ChileChile16,704,27287.0%
South AfricaSouth Africa16,404,84127.3%
Sri LankaSri Lanka15,888,05373.9%
UzbekistanUzbekistan15,858,04846.7%
CambodiaCambodia14,079,04983.1%
MyanmarMyanmar13,905,79525.4%
VenezuelaVenezuela13,858,05748.3%
NetherlandsNetherlands13,104,28676.3%
EcuadorEcuador12,918,84372.2%
UkraineUkraine12,554,33328.9%
CubaCuba10,094,40189.2%
United Arab EmiratesUnited Arab Emirates9,801,52998.1%
PortugalPortugal9,053,90189.0%
BelgiumBelgium8,777,11775.5%
NepalNepal8,736,53229.4%
KazakhstanKazakhstan8,574,04345.1%
RomaniaRomania7,331,73438.3%
SwedenHow Corona Vaccine Works (with video) Vaccine Mechanism of Action
GreeceGreece6,850,75766.1%
Dominican RepublicDominican Republic6,832,34062.4%
IraqIraq6,660,61416.2%
Czech RepublicCzech Republic6,453,40660.2%
AlgeriaAlgeria6,446,37314.4%
IsraelIsrael6,261,89267.4%
AustriaAustria6,169,68268.2%
HungaryHungary6,013,00762.4%
TunisiaTunisia5,858,72049.1%
NigeriaNigeria5,823,0132.8%
AngolaAngola5,802,57417.1%
SwitzerlandSwitzerland5,797,43766.5%
GuatemalaGuatemala5,612,33430.8%
SingaporeSingapore5,071,14893.0%
AzerbaijanAzerbaijan5,033,34649.2%
MozambiqueMozambique4,858,83015.1%
RwandaRwanda4,774,59636.0%
BoliviaBolivia4,688,73139.6%
Hong KongHong Kong4,683,29462.0%
DenmarkDenmark4,527,85877.9%
El SalvadorEl Salvador4,390,90067.4%
FinlandFinland4,259,70376.8%
NorwayNorway4,222,89277.3%
JordanJordan4,057,63439.5%
HondurasHonduras3,957,95739.3%
KenyaKenya3,905,2157.1%
UgandaUganda3,838,4398.2%
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COVID-19 vaccines: modes of immune activation and future challenges

The new vaccines against SARS-CoV-2 are novel in terms of specificity, their wide dissemination across the global population and the inclusion of newly licensed mRNA platforms. We discuss here how the approved vaccines trigger innate immunity to promote durable immunological memory and consider the future implications of protecting populations with these vaccines.

The global SARS-CoV-2 pandemic has caused significant loss of life, profound disruption to lives and livelihoods, and widespread economic, sociological and psychological damage. How Corona Vaccine Works (with video) Vaccine Mechanism of Action COVID-19 involving acute respiratory distress syndrome (ARDS), multi-organ failure and death remains the most serious threat from infection, but long-term sequelae from mild disease have also been reported. The high transmissibility, presence of asymptomatic carriers and emergence of new variants have had a prolonged effect on the global population for the past year and counting. Vaccination constitutes the most promising path back to ‘normal life’; here, we discuss how the newly approved vaccines can mobilize innate and adaptive immune responses, implications for their durability, and ongoing and future challenges for protecting the population.

Approved vaccine formulations

Significant advances in cutting edge vaccine technologies over the past decade have resulted in two main types of SARS-CoV-2 vaccines now being approved for emergency use — an unprecedented achievement in modern medical science. The approved vaccines developed by Pfizer and Moderna use mRNA technology and lipid nanoparticle (LNP) delivery systems, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, while the approved formulations by AstraZeneca, Johnson and Johnson and Gam-COVID-vac (Sputnik V) contain DNA delivered within non-replicating recombinant adenovirus (AdV) vector systems1,2,3,4. Both the mRNA and AdV vaccines encode production of the SARS-CoV-2 spike (S) protein, which is the primary target for neutralizing antibodies generated from natural infection and for therapeutic monoclonal antibodies1. To date, results from the phase III clinical trials showed that both the Pfizer/BioNTech (BNT162b2) and Moderna (mRNA-1273) mRNA vaccines achieved 90–95% efficacy in protecting against COVID-19 (refs1,2), while the AdV vaccines (ChAdOx1 nCoV-19) and Gam-COVID-vac (Sputnik V) showed protection at a slightly lower efficacy (average 70% and 91%, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, respectively)3,4. Both vaccine types generate significant neutralizing antibody titres and virus-specific T cell responses as measured in blood 2–4 weeks post inoculation5,6. These trials, which collectively involved more than 100,000 participants, provide compelling rationale for expedient and widespread vaccination of the global population. While the AdV vaccine platform has been licensed for Ebola, the mRNA vaccine platform represents a newly licensed formulation. Thus, we still have much to learn about how these vaccines mobilize the immune response, the 3dMark free download Archives of protection and how to further optimize them to protect against new variants, strains and disease manifestations.

Triggering innate and adaptive responses

To stimulate adaptive immunity, a vaccine requires a pathogen-specific immunogen as well as an adjuvant — the latter stimulates the innate immune system and provides the necessary second signal for T cell activation. An optimal adjuvant stimulates innate immunity without inducing systemic inflammation that could elicit severe side effects. For mRNA vaccines, the mRNA can serve as both immunogen (encoding the viral protein) and adjuvant, owing to intrinsic immunostimulatory properties of RNA. Upon entry into cells, single-stranded RNA (ssRNA) and double-stranded RNA (dsRNA) are recognized by various endosomal and cytosolic innate sensors that form a critical part of the innate immune response to viruses. Endosomal Toll-like receptors (TLR3 and TLR7) bind to ssRNA in the endosome, while components of the inflammasome such as MDA5, RIG-I, NOD2 and PKR bind to ssRNA and dsRNA in the cytosol, resulting in cellular activation, and production of type I interferon and multiple inflammatory mediators7 (Fig. 1). The current vaccines contain purified, in vitro-transcribed single-stranded mRNA with modified nucleotides to reduce binding to TLR and immune sensors, thus limiting excessive production of type I interferon and its inhibitory function on cellular translation (see ref.7). The LNP carrier further protects the mRNA, can target delivery to lymphatics and promote protein translation in lymph nodes (LNs)7. Once in the LN, the LNP is engulfed by dendritic cells (DCs), which subsequently produce and present the antigen to T cells for activation of the adaptive immune response.

The two vaccine formulations — mRNA encoding the SARS-CoV-2 spike (S) protein encapsulated in lipid nanoparticles or adenovirus (AdV) vectors encoding the S protein — gain entry into dendritic cells (DCs) at the injection site or within lymph nodes, resulting in production of high levels of S protein. In addition, innate sensors are triggered by the intrinsic adjuvant activity of the vaccines, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, resulting in production of type I interferon and multiple pro-inflammatory cytokines and chemokines. RNA sensors such as Toll-like receptor 7 (TLR7) and MDA5 are triggered by the mRNA vaccines, and TLR9 is the major double-stranded DNA sensor for the AdV vaccine. The resultant activated DCs present antigen and co-stimulatory molecules to S protein-specific naive T cells, which become activated and differentiated into effector cells to form cytotoxic T lymphocytes or helper T cells. T follicular helper (TFH) cells help S protein-specific B cells to differentiate into antibody-secreting plasma cells and promote the production of high affinity anti-S protein antibodies. Following vaccination, S protein-specific memory T cells and B cells develop and circulate along with high affinity SARS-CoV-2 antibodies, which together help prevent subsequent infection with SARS-CoV-2. TCR, T cell receptor.

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The How Corona Vaccine Works (with video) Vaccine Mechanism of Action vaccines also contain inherent adjuvant properties, although these reside with the virus particle that encases the DNA encoding the immunogen. Following injection, AdV particles target innate immune cells like DCs and macrophages and stimulate innate immune responses by How Corona Vaccine Works (with video) Vaccine Mechanism of Action multiple pattern-recognition receptors including those that bind dsDNA — in particular TLR9 — to induce type I interferon secretion8. Unlike AdV vectors, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, mRNA vaccines do not engage TLR9, but both vaccine formulations converge on the production of type I interferon (Fig. 1). Type I interferon-producing DCs and other cells that have taken up the vaccine-derived nucleic acids encoding the S protein can deliver both an antigenic and inflammatory signal to T cells in LNs draining the injection site. This activates S protein-specific T cells and mobilizes adaptive immunity against SARS-CoV-2 (Fig. 1).

The ability of mRNA and AdV vaccines to promote intracellular production of S protein along with innate immune responses How Corona Vaccine Works (with video) Vaccine Mechanism of Action prime both CD8+ and CD4+ T cells to differentiate into effector and memory subsets. In particular, vaccine-driven production of type I interferon promotes differentiation of CD4+ and CD8+ effector T cells producing inflammatory and cytotoxic mediators, and CD4+ T follicular helper (TFH) cells, which promote B cell differentiation into antibody-secreting plasma cells (Fig. 1). Both the mRNA and AdV vaccines require two doses spaced 3–4 weeks apart to promote optimal protection and have been associated with mild to moderate side effects, including injection site pain, transient fever and chills, which can be augmented with the second dose. This secondary enhancement of the inflammatory response can derive from short-term changes to innate cells like macrophages through a phenomenon called ‘trained immunity’9, and/or from activation of memory T cells and B cells generated from the initial injection. Type I interferon has been shown to amplify T cell memory and promote B cell differentiation and survival, suggesting vaccine-associated inflammation in the booster can further promote generation and perpetuation of long-term immunological memory.

Durability and future challenges

Preclinical and early results from human trials show that both vaccines generate anti-S protein IgG and virus-specific neutralizing antibody responses for several months post-vaccination5,6, while the T cell data remain to be fully elucidated. This short-term durability is likely sufficient for curtailing the spread of SARS-CoV-2 and beginning the path back to normalcy. However, the global pervasiveness of SARS-CoV-2 along with the emergence of S protein variants could potentially limit vaccine efficacy. Eradication of SARS-CoV-2 from the population may prove challenging, owing to reservoirs within individuals who are not vaccinated and/or in other animal species. New vaccine formulations containing the variant S sequences and additional SARS-CoV-2 proteins could be generated, and annual or semi-annual SARS-CoV-2 vaccines could be given for persisting strains and/or seasonal variants. The mRNA vaccine formulation is ideally suited for repeat or modified vaccination as different mRNAs containing mutant S proteins can be rapidly synthesized and included within the LNP carrier. By contrast, the AdV vector formulation generates AdV-specific immunity, which can limit efficacy of repeated boosters owing to immune-mediated clearance of the vector.

The unprecedented mass ReiBoot Pro Crack 2021 v7.6.1.0 With Activation Key Free Key Download simultaneous vaccination of the global population will undoubtedly reveal heterogeneity in vaccination responses and some individuals may not generate robust antibody responses or be protected. How Corona Vaccine Works (with video) Vaccine Mechanism of Action to respiratory viruses can be mediated by tissue-resident memory T (TRM) cells that are established in the lung during the initial infection and retained as non-circulating populations that mediate protective responses in situ upon viral re-challenge10. TRM cells can be generated from site-specific vaccination with attenuated viral vaccine formulations10. It would be interesting to determine whether intranasal delivery of mRNA vaccines can promote TRM cells and protection in the lung. The development of self-replicating mRNA vaccines (which mimic viral replication) may also enhance protective T cell immunity. Such alterations in formulation and delivery route could be used to optimize the vaccines according to immune status and age.

In conclusion, the SARS-CoV-2 pandemic has accelerated the licensing of promising vaccine formulations that provide hope for fortifying our immune systems against the current and future emerging pandemics.

References

  1. 1.

    Baden, L. R. et al. Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N. Engl. J. Med.384, 403–416 (2021).

    CASArticle Google Scholar

  2. 2.

    Polack, F. P. et al. Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine. N. Engl. J. Med.383, 2603–2615 (2020).

    CASArticle Google Scholar

  3. 3.

    Voysey, M. et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet397, 99–111 (2021).

    CASArticle Google Scholar

  4. 4.

    Logunov, D. Y. et al. Safety and efficacy of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine: an interim analysis of a randomised controlled phase 3 trial in Russia. Lancet397, 671–681 (2021).

    CASArticle Google Scholar

  5. 5.

    Widge, A. T. et al. Durability of responses after SARS-CoV-2 mRNA-1273 vaccination. N. Engl. J. Med.384, 80–82 (2021).

    CASArticle Google Scholar

  6. 6.

    Sahin, U. et al. COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses. Nature586, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, 594–599 (2020).

    CASArticle Google Scholar

  7. 7.

    Pardi, N., Hogan, M. J., Porter, F. W. & Weissman, D. mRNA vaccines — a new era in vaccinology. Nat. Rev. Drug. Discov.17, 261–279 (2018).

    CASArticle Google Scholar

  8. 8.

    Sayedahmed, E. E., Elkashif, A., Alhashimi, M., Sambhara, S, How Corona Vaccine Works (with video) Vaccine Mechanism of Action. & Mittal, S. K, How Corona Vaccine Works (with video) Vaccine Mechanism of Action. Adenoviral vector-based vaccine platforms for developing the next generation of influenza vaccines. Vaccines8, 574 (2020).

    Article Google Scholar

  9. 9.

    Yao, Y. et al. Induction of autonomous memory alveolar macrophages requires t cell help and is critical to trained immunity. Cell175, 1634–1650 (2018).

    CASArticle Google Scholar

  10. 10.

    Paik, D. H. & Farber, D. L. Anti-viral protective capacity of tissue resident memory T cells. Curr. Opin. Virol.46, 20–26 (2020).

    Article Google Scholar

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Affiliations

  1. Department of Immunology and Microbiology, Scripps Research institute, La Jolla, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, CA, USA

    John R. Teijaro

  2. Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA

    Donna L. Farber

  3. Department of Surgery, Columbia University Irving Medical Center, New York, NY, USA

    Donna L. Farber

Corresponding authors

Correspondence to John R. Teijaro or Donna L. Farber.

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Competing interests

The authors declare no competing interests.

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Teijaro, J.R., Farber, D.L. COVID-19 vaccines: modes of immune activation and future challenges. Nat Rev Immunol21, 195–197 (2021). https://doi.org/10.1038/s41577-021-00526-x

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What are mRNA vaccines and how do they work?

Vaccines help prepare the body to fight foreign invaders (pathogens such as bacteria or viruses), to prevent infection. All vaccines introduce into the body a harmless piece of a particular bacteria or virus, triggering an immune response. Most vaccines contain a weakened or dead bacteria or virus. However, scientists have developed a new type of vaccine that uses a molecule called messenger RNA (or mRNA for short) rather than part of an actual bacteria or virus. Messenger RNA is a type of RNA that is necessary for protein production. In cells, mRNA uses the information in genes to create a blueprint for making proteins. Once cells finish making a protein, they quickly break down the mRNA. mRNA from vaccines does not enter the nucleus and does not alter DNA.

mRNA vaccines work by introducing a piece of mRNA that corresponds to a viral protein, usually a small piece of a protein found on the virus’s outer membrane. (Individuals who get an mRNA vaccine are not exposed to the virus, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, nor can they become infected by the vaccine.) Using this mRNA blueprint, cells produce the viral protein. As part of a normal immune response, the immune system recognizes that the protein is foreign and produces specialized proteins called antibodies. Antibodies help protect the body against infection by recognizing individual viruses or other pathogens, attaching to them, and marking the pathogens for destruction. Once produced, antibodies remain in the body, even after the body has rid itself of the pathogen, so that the immune system can quickly respond if exposed again. If a person is exposed to a virus after receiving mRNA vaccination for it, antibodies can quickly recognize it, attach to it, and mark it for destruction before it can cause serious illness.

Like all vaccines in the United States, mRNA vaccines require authorization or approval from the Food and Drug Administration (FDA) before they can be used. Currently vaccines for COVID-19, the disease caused by the SARS-CoV-2 coronavirus, are the only authorized or approved mRNA vaccines. These vaccines use mRNA that directs cells to produce copies of a protein on the outside of the coronavirus known as the “spike protein”. Researchers are studying how mRNA might be used to develop vaccines for additional infectious diseases.

Scientific journal articles for further reading

Jain S, Venkataraman A, Wechsler ME, Peppas NA. Messenger RNA-based vaccines: Past, present, and future directions in the context of the COVID-19 pandemic. Adv Drug Deliv Rev. 2021 Oct 9;179:114000. doi: 10.1016/j.addr.2021.114000. Epub ahead of print. PMID: 34637846; PMCID: PMC8502079.

Verbeke R, Lentacker I, De Smedt SC, Dewitte H. The dawn of mRNA vaccines: The COVID-19 case. J Control Release. 2021 May 10;333:511-520. doi: 10.1016/j.jconrel.2021.03.043. Epub 2021 Mar 30. PMID: 33798667; PMCID: PMC8008785.

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Covid: How does the Oxford-AstraZeneca vaccine work?

Image source, Getty Images

People under the age of 40 are to be offered an alternative to the Oxford-AstraZeneca vaccine in the UK as a precaution, after a review of all the latest evidence by vaccine advisers and safety experts.

The UK's medicine regulator - the MHRA - says the benefits of the vaccine still outweigh the risks for the vast majority of people.

What is the latest advice?

The Joint Committee on Vaccination and Immunisation (JCVI) - the body which advises the government - has now recommended that "adults aged 18- 39 years with no underlying health conditions are offered an alternative to the Oxford-AstraZeneca vaccine, if available, and if it does not How Corona Vaccine Works (with video) Vaccine Mechanism of Action delays in having the vaccine".

Data from the MHRA suggests there's a very small - but slightly higher than normal - incidence of a rare type of clot in younger adult age groups, particularly when the risk of being infected with coronavirus is very low, as it is now.

The risk of a clot is roughly one in 100,000 for people in their 40s, and rises to one in 60,000 for people in their 30s.

Based on the current data, the following is advised:

  • Anyone who experiences clotting after a first dose of the vaccine should not receive a second dose
  • People with a history of blood disorders (at risk of clotting) should only have the AstraZeneca when the benefits outweigh the risks
  • Pregnant women should talk to their GPs about the benefits and risks

What's known about the risk?

The MHRA looked into UK cases of rare blood clots in people who had recently received the Oxford-AstraZeneca vaccine.

It found 242 cases of clotting cases and 49 deaths after an estimated 28.5 million AstraZeneca vaccines doses were administered across the UK up to 28 April.

The MHRA said about four people in a million would normally be expected to develop this particular kind of blood clot - though the fact they are so rare makes the usual rate hard to estimate.

And the regulator said it had not been proven that the jab had caused the clots.

Its head, Dr June Raine, said while the link was "firming up", more evidence would be needed.

The benefits of the AstraZeneca vaccine outweigh the risks of the virus - hospitalisation and death - for the vast majority of people, she said. But for younger age groups it was more "finely balanced".

What are these rare blood clots?

The MHRA study looked at people who had developed clots associated with a low level of platelets after receiving the Oxford-AstraZeneca vaccine.

Platelets are tiny blood cells that help your body form clots to stop bleeding.

Among these clots is a type called a Cerebral Venous Sinus Thrombosis (CSVT).

CVST occurs when a blood clot forms in large veins in the head - stopping blood from draining out of the brain.

As a result, blood cells may break and leak into brain tissue - ultimately leading to a stroke.

The clot can occur naturally and are more common, but still very rare, in younger women.

What symptoms should I watch out for?

The MHRA says anyone who has these symptoms four or more days after receiving the Oxford-AstraZeneca vaccine should seek prompt medical advice:

  • A severe or persistent headache
  • Blurred vision
  • Chest pain
  • Shortness of breath
  • Swollen legs
  • Persistent abdominal pain
  • Unusual skin bruising
  • Pinpoint spots (not including the injection site)

Covid infection itself can make clots more likely, stresses the MHRA.

What have other countries said about the AstraZeneca vaccine?

The European Medicines Agency (EMA) has said clotting should be listed as a very rare vaccine side effect.

After a study looking at 86 such cases in the EU, the EMA concluded the benefits of the vaccine outweighed the risk and that there was no definite causal link.

Nevertheless, Denmark has stopped its AstraZeneca rollout completely - and Germany, How Corona Vaccine Works (with video) Vaccine Mechanism of Action, Spain, Italy and Ireland have suspended use of the vaccine in people under 60.

France is recommending it only be given to those aged 55 or over, while Australia says people aged under 50 should get the Pfizer jab instead.

How does the Oxford-AstraZeneca vaccine work?

It is made ZULU DJ soft 3.27 crack serial keygen a weakened version of a common cold virus (known as an adenovirus) from chimpanzees. It has been modified to contain genetic material shared by the coronavirus - although it can't cause the illness.

Once injected, it teaches the body's immune system how to fight the real virus.

Does the vaccine protect against new variants?

Experts are studying all of the current coronavirus vaccines to check how well they work against new, mutated variants of the virus.

The government's deputy chief medical officer, Jonathan Van Tam, says there is "plenty of evidence" the vaccines appear to be effective against the Kent variant which is dominant in the UK.

There is less evidence about protection against other variants, such as those identified in Brazil and South Africa.

However a study of around 2,000 people suggests, while the Oxford-AstraZeneca vaccine may offer more limited protection against mild and moderate disease caused by the South Africa variant. it should still protect against severe disease.

More on this story

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How the vaccine works

Imperial’s vaccine against COVID-19 will train the body’s immune system to recognise the virus and help it to defend itself against a future attack.

Traditional vaccines are often based on a weakened form of a virus or parts of it, but the Imperial vaccine is based on a new method. Instead, it uses bits of genetic Super Woden GP Free Download (called self-amplifying RNA), rather than bits of the virus.

Once injected into muscle, the cells should produce copies of a protein found on the outside of the virus. This trains the immune system to respond to the coronavirus so the body can easily recognise it as a threat in future.

The upcoming trials will be the first time the vaccine has been tested in humans and will show what dose is needed to produce an immune response safely. 

How was the vaccine made?

Coronaviruses are covered in spike proteins that stick out from their surface and which the virus uses to get into cells. Once inside, the viruses can produce thousands/millions of copies of themselves and can then spread to infect other cells.

When the outbreak first emerged, scientists in China isolated samples of the SARS CoV-2 virus from patients with COVID-19 and were able to sequence its genetic code – which is made up Bandicut 3.5.0.599 crack serial keygen Ribonucleic Acid (RNA).

The Imperial team, led by Professor Robin Shattock, focused on the part of this sequence that holds the blueprint for the spike protein. They were able to recreate the sequence using enzymes in the lab and generate copies of the RNA without the need for animal cells or human stem cells.

The result is short strands of self-amplifying RNA which hold all the information needed to make the spike protein, How Corona Vaccine Works (with video) Vaccine Mechanism of Action. These strands are packaged into tiny fat droplets, which form the final vaccine.

How does the vaccine work?

When the Imperial vaccine is injected (into the arm, or the leg) the cells of the muscle will take up the tiny fat droplets and the RNA they contain.

Once inside the cell, the self-amplifying RNA produces copies itself, which can instruct the cell’s own machinery to make the coronavirus protein. This process takes place in the cytoplasm of the cell and so doesn’t affect or change the cell’s own genetic material (its DNA).

The muscle CorelDRAW Graphics Suite 2021 Crack Free Download Full Version + Serial Number will then produce lots of the spike protein – but not the whole virus. Some of the proteins will be presented on the surface of the muscle cells, as part of the normal process the body uses to show the immune system what’s going on inside cells.

When the immune system comes across these tiny spikes, it recognises them as foreign and creates antibodies. These antibodies have an important role in fighting viruses as they bind to the spike proteins and may prevent the virus from infecting cells. This process also creates a lasting memory of the spikes so that the body ever comes across them again, it will recognise them and be able to mount a quick response.

Since the outbreak at the end of 2019, the novel coronavirus SARS CoV-2 has spread rapidly around the world and caused hundreds of thousands of deaths. One of the reasons it has been so harmful is that it How Corona Vaccine Works (with video) Vaccine Mechanism of Action a new or novel virus, and people had no immunity against it.

Ultimately, the aim of the vaccine is to trick the body into thinking it has already seen the virus and made an immune response, so when you come into contact with it in real life, you should already be immune.

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Understanding mRNA COVID-19 Vaccines

COVID-19 mRNA Vaccines Have Been Rigorously Evaluated for Safety

mRNA vaccines have been held to the same rigorous safety and effectiveness standardsexternal icon as all other types of vaccines in the United States. The only COVID-19 vaccines the Food and Drug Administration (FDA) makes available for use in the United States (by approval or emergency use authorization) are those that meet these standards.

mRNA Vaccines Are Newly Available to the Public But Have Been Studied for Decades

Researchers have been studying and working with mRNA vaccines for decades. Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means vaccines can be developed and produced in large quantities faster than with other methods for making vaccines.

mRNA vaccines have been studied before for flu, Zika, rabies, and cytomegalovirus (CMV). As soon as the necessary information about the virus that causes COVID-19 was available, scientists began designing the mRNA instructions for cells to build the unique spike protein into an mRNA vaccine.

Future mRNA vaccine technology may allow for one vaccine to provide protection against multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases.

Beyond vaccines, cancer research has used mRNA to trigger the immune system to target specific cancer cells.

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How Corona Vaccine Works (with video) Vaccine Mechanism of Action - think

How Corona Vaccine Works – Vaccine Mechanism of Action can be seen on this page. You can read How Corona Vaccine works and also watch a complete explanation video for the same. How any corona vaccine kills the virus is described in the article. If you are infected with Corona, you will be given prescribed medical treatment by the government.

How Corona Vaccine Works

If you get the Corona Vaccine already, then the chances of getting a Corona infection will be only 10%. So far millions of people have lost their lives due to Covid 19 and sars-cov-2 in the country. Corona is continuously growing in the country. According to the data released by the government, the country is currently suffering from a severe outbreak of Corona. How Corona Vaccine Works The answer to this question has been given in the article below.

Currently, vaccination is being done to prevent corona infection in the country and the world. Any corona vaccine given makes your body stronger to fight the corona. There are some ingredients found in the vaccine that help eliminate this infection. After vaccination, antibodies that fight against the corona in your body begin to form. Any corona vaccine given in your body makes the ‘immune system’ stronger.

Some common side effects can be seen in your body after the vaccine is applied. Many people have not seen any side effects even after applying the Corona vaccine. Mild fever or rash may be common side effects of the vaccine. As soon as you get the vaccine applied, at the same time your body starts increasing the strength to fight against diseases in the body to fight the corona.

How Corona Vaccine WOrks

How Covishield Corona Vaccine Works

According to the Center for Disease Control and Prevention (CDC) America, the vaccine keeps your body out of the grip of corona infection. The vaccine has been shown to be more beneficial for you than other drugs. After applying Covishield Vaccine, your body kills the corona inside the body through its immunity. The Covishield vaccine protects your body from contracting it instead of eliminating the virus.

The Covishield vaccine is currently being used in India. According to the citizens who have been given this vaccine, now their body is more capable of fighting diseases than before. As soon as the vaccine is introduced, the body acts as a shield to fight the coronavirus. The vaccine checks the coronavirus and prevents it from entering the body. If the virus penetrates into the body, the vaccine creates antibodies and exits the body.

Corona Vaccines:

How Pfizer Covid Vaccine Works

Memory cells are promoted in your body after applying Pfizer covid vaccine. With Pfizer, the body protects you from future corona infections. If you develop a corona after the vaccine is in place, there is a very low chance of it becoming a serious symptom. Within a few hours of the vaccine, the vaccine starts going to the cells of your body and starts making antibodies.

Also check:

Black Fungal Disease Infection Symptoms, Fungus Cause,Treatment

Once the vaccine is in place, your risk of developing corona is reduced by 95%. If you become corona infected due to any negligence, then the risk of your life is only 1%. If the virus enters the body after vaccination, it will not be able to harm your cells. How will the Pfizer vaccine work? We will soon tell you through the video.

How Covid Vaccine Works Video

This video is created by the Professor of How YouTube Channel. If you find this video informative and also like the work he does, please Click Here to subscribe to his channel.

You can understand how the vaccine is able to fight the corona through the video below. The corona targets the cell present in the body as it enters the body. The coronavirus has to enter through the ace-2 receptor to enter the cell. If the coronavirus is not successful in this, then it is eradicated by itself. The corona must use its spike protein to enter the cell via the Ace-2 receptor.

To prevent the corona from doing so the spike proteins of the corona have to be covered through antibodies. To generate these antibodies in the body, you have to take help from the vaccine. The vaccine helps in making essential proteins in the body through mRNA.

Also check:

CBSE Class 12 exams will be cancelled ? Here’s is the Analysis and answer

You can get every information about this vaccine through the video given in the article. The video provides easy answers to questions about what is a corona, what is an mRNA, how does a corona vaccine work, what elements are added to a vaccine, etc.

Covid Vaccine Mechanism of Action

The easiest way to understand the Covid 19 Vaccine Mechanism of Action is explained in the video above. The cell in the body generates ribozyme proteins through the vaccine mRNA. Ribozyme generates the required proteins by copy-pasting the mRNA given by the vaccine in a way. For more details, you should watch the given video.

To get other information about the vaccine, you can read the article on our home page. For other information related to the country and the world, you can subscribe to the website. You can send us your complaint or question in the comment box below. All your questions about Corona have answered in the video above.

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Understanding mRNA COVID-19 Vaccines

COVID-19 mRNA Vaccines Have Been Rigorously Evaluated for Safety

mRNA vaccines have been held to the same rigorous safety and effectiveness standardsexternal icon as all other types of vaccines in the United States. The only COVID-19 vaccines the Food and Drug Administration (FDA) makes available for use in the United States (by approval or emergency use authorization) are those that meet these standards.

mRNA Vaccines Are Newly Available to the Public But Have Been Studied for Decades

Researchers have been studying and working with mRNA vaccines for decades. Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means vaccines can be developed and produced in large quantities faster than with other methods for making vaccines.

mRNA vaccines have been studied before for flu, Zika, rabies, and cytomegalovirus (CMV). As soon as the necessary information about the virus that causes COVID-19 was available, scientists began designing the mRNA instructions for cells to build the unique spike protein into an mRNA vaccine.

Future mRNA vaccine technology may allow for one vaccine to provide protection against multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases.

Beyond vaccines, cancer research has used mRNA to trigger the immune system to target specific cancer cells.

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Video Transcript: What is the mRNA Vaccine Platform?

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On-screen text:

What is the mRNA Vaccine Platform? For Healthcare Professionals

[SPEECH]

Let’s take a quick look at Moderna’s mRNA platform, which forms the basis of the Moderna COVID‑19 Vaccine.

But first, please be aware of the following important information about the Moderna COVID‑19 Vaccine.

[DESCRIPTION AND SPEECH]

On-screen text and voice:

The Moderna COVID‑19 Vaccine has not been approved or licensed by the US Food and Drug Administration (FDA), but has been authorized for emergency use by FDA, under an Emergency Use Authorization (EUA), to prevent Coronavirus Disease 2019 (COVID‑19) for use in individuals 18 years of age and older.

The EUA for the Moderna COVID‑19 Vaccine is in effect for the duration of the COVID‑19 EUA declaration justifying emergency use of the product, unless terminated or revoked (after which the products may no longer be used).

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On-screen text:

For information on the authorized use of the Moderna COVID‑19 Vaccine and mandatory requirements of the EUA, please review the Fact Sheet for Healthcare Providers Administering Vaccine (Vaccination Providers) and Full EUA Prescribing Information available at https://www.modernatx.com/covid19vaccine-eua/eua-fact-sheet-providers.pdf.

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The image of a scientific journal is displayed, with the words “Moderna”,“mRNA”, and “Est.2010” on the cover.

On-screen text:

IMPORTANT SAFETY INFORMATION

Contraindications

Do not administer the Moderna COVID‑19 Vaccine to individuals with a known history of severe allergic reaction (e.g., anaphylaxis) to any component of the Moderna COVID‑19 Vaccine.

[SPEECH]

The name Moderna might be new to you, but we’ve been focused on research and development of new medicines since 2010.

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The logos of several national and international health agencies and research organizations appear: NIH, NIAID, BARDA, Institut Pasteur, Karolinska Institutet.

[SPEECH]

Our research, including partnerships with leading health agencies and research organizations, has focused on a new class of medicines and vaccines based on messenger RNA, or mRNA.

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On-screen text:

FIGURE 1. THE CENTRAL DOGMA

A visual representation of DNA appears with an arrow pointing to a strand of mRNA, which has an arrow pointing to a protein.

[SPEECH]

As you know from basic biology, mRNA is used by every cell in the body to make the proteins that drive many aspects of human health and disease.

However, they fall short to find types greatest for are expanded and usually run in the background.

The image of a vial appears. Next to it is a large image of different viruses with an X over them.

Then the image changes to a vial with an mRNA strand next to it.

The image zooms into the mRNA as a ribosome appears alongside it within a cell. The image shows the ribosome-mRNA complex producing a viral antigen.

[SPEECH]

A vaccine based on mRNA does not include any virus, but instead a sequence of nucleoside-modified mRNA encoding viral antigens.

This technology helps the body itself produce the viral antigen, against which the body mounts an immune response.

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Everything fades except for the image of the mRNA strand.

[SPEECH]

The mRNA is nonreplicating, and is only present in the cell transiently. It does not enter the cell nucleus or interact with DNA.

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The image fades out and is replaced with the image of an mRNA strand enclosed within a lipid particle.

On-screen text:

No adjuvants or preservatives

Can be stored under refrigeration up to 30 days after thawing

No dilution required

[SPEECH]

Moderna has developed lipid particles as vehicles to deliver the mRNA into cells. This lipid technology means that the Moderna COVID‑19 Vaccine does not require adjuvants or preservatives and can be stored under refrigerated conditions for up to 30 days, once it is thawed. Please check the Fact Sheet for Vaccination Providers for details on storage and handling of the Moderna COVID‑19 Vaccine.

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A representation of the SARS‑CoV‑2 virus appears next to the lipid particle. Then the virus changes and the mRNA changes at the same time.

[SPEECH]

All of this research into Moderna’s mRNA platform allows for an approach that can be adapted to target specific viruses, including SARS‑CoV‑2, the virus that causes COVID‑19, by placing the mRNA code for the viral target within the platform.

Please note the following important safety information for the Moderna COVID‑19 Vaccine.

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On-screen text:

Important Safety Information for Moderna COVID‑19 Vaccine

[DESCRIPTION AND SPEECH]

On-screen text and voice:

AUTHORIZED USE

Moderna COVID‑19 Vaccine is authorized for use under an Emergency Use Authorization (EUA) for active immunization to prevent coronavirus disease 2019 (COVID‑19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) in individuals 18 years of age and older. Moderna COVID‑19 Vaccine is investigational and not approved by FDA.

IMPORTANT SAFETY INFORMATION

Contraindications

Do not administer the Moderna COVID‑19 Vaccine to individuals with a known history of severe allergic reaction (e.g., anaphylaxis) to any component of the Moderna COVID‑19 Vaccine.

Warnings and Precautions

  • Management of Acute Allergic Reactions: Appropriate medical treatment to manage immediate allergic reactions must be immediately available in the event an acute anaphylactic reaction occurs following administration of the Moderna COVID‑19 Vaccine.
  • Monitor Moderna COVID‑19 Vaccine recipients for the occurrence of immediate adverse reactions according to the Centers for Disease Control and Prevention guidelines (https://www.cdc.gov/vaccines/covid-19/clinical-considerations/managing-anaphylaxis.html)
  • Myocarditis and Pericarditis: Postmarketing data demonstrate increased risks of myocarditis and pericarditis, particularly within 7 days following the second dose. The CDC has published considerations related to myocarditis and pericarditis after vaccination, including for vaccination of individuals with a history of myocarditis or pericarditis (https://www.cdc.gov/vaccines/covid-19/clinical-considerations/myocarditis.html).
  • Syncope (fainting): May occur in association with administration of injectable vaccines. Procedures should be in place to avoid injury from fainting.
  • Altered Immunocompetence: Immunocompromised persons, including individuals receiving immunosuppressive therapy, may have a diminished response to the Moderna COVID‑19 Vaccine.
  • Limitations of Vaccine Effectiveness: The Moderna COVID‑19 Vaccine may not protect all vaccine recipients.

Adverse Reactions

Adverse reactions reported in a clinical trial following administration of the Moderna COVID‑19 Vaccine include pain at the injection site, fatigue, headache, myalgia, arthralgia, chills, nausea/vomiting, axillary swelling/tenderness, fever, swelling at the injection site, and erythema at the injection site.

The following adverse reactions have been reported following administration of the Moderna COVID-19 Vaccine during mass vaccination outside of clinical trials:

  • Severe allergic reactions, including anaphylaxis
  • Myocarditis
  • Pericarditis
  • Syncope

Additional adverse reactions, some of which may be serious, may become apparent with more widespread use of the Moderna COVID‑19 Vaccine.

Reporting Adverse Events and Vaccine Administration Errors

The vaccination provider is responsible for mandatory reporting of the following to the Vaccine Adverse Event Reporting System (VAERS):

  • vaccine administration errors whether or not associated with an adverse event
  • serious adverse events (irrespective of attribution to vaccination)
  • cases of Multisystem Inflammatory Syndrome (MIS) in adults
  • cases of COVID‑19 that result in hospitalization or death

Complete and submit reports to VAERS online at https://vaers.hhs.gov/reportevent.html. For further assistance with reporting to VAERS, call 1-800-822-7967. Reports should include the words “Moderna COVID‑19 Vaccine EUA” in the description section of the report.

Report to ModernaTX, Inc. by calling 1-866-MODERNA (1-866-663-3762) or provide a copy of the VAERS form by faxing 1-866-599-1342 or emailing ModernaPV@modernatx.com.

Pregnancy and Lactation

Available data on Moderna COVID‑19 Vaccine administered to pregnant women are insufficient to inform vaccine-associated risks in pregnancy. Data are not available to assess the effects of Moderna COVID‑19 Vaccine on the breastfed infant or on milk production/excretion.

Dosing and Schedule

The Moderna COVID‑19 Vaccine is administered intramuscularly as a series of two doses (0.5 mL each) 1 month apart.

There are no data available on the interchangeability of the Moderna COVID‑19 Vaccine with other COVID‑19 vaccines to complete the vaccination series. Individuals who have received one dose of Moderna COVID‑19 Vaccine should receive a second dose of Moderna COVID‑19 Vaccine to complete the vaccination series.

A third dose of the Moderna COVID-19 Vaccine (0.5 mL) administered at least 28 days following the second dose of this vaccine is authorized for administration to individuals at least 18 years of age who have undergone solid organ transplantation, or who are diagnosed with conditions that are considered to have an equivalent level of immunocompromise.

For more information, see the Fact Sheet for Healthcare Providers Administering Vaccine (Vaccination Providers) and Full EUA Prescribing Information at https://www.modernatx.com/covid19vaccine-eua/eua-fact-sheet-providers.pdf.

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The Moderna logo is displayed, along with the website ModernaTX.com.

[SPEECH]

Visit ModernaTX.com to learn more about mRNA technology.

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Job code is displayed on screen:

US-COV-2100130 09/2021

[END OF TRANSCRIPT]

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How COVID-19 vaccines work - mRNA and viral vector

Vaccines are the most effective way to prevent infectious diseases. They prepare your immune system (your body's natural defences) to recognise and defend itself against a specific virus.

All vaccines do this. But different types of vaccine work in different ways.

Some types of vaccine contain a live virus. For example, the flu vaccine contains a small amount of the flu virus. But none of the COVID-19 vaccines in use have the COVID-19 virus in them. They work differently.

There are currently 2 types of COVID-19 vaccine in use:

All vaccines are tested for safety and effectiveness before they can be used. The HSE only uses a vaccine if it meets the required standards of safety and effectiveness.

mRNA vaccines

The Pfizer/BioNTech and Moderna COVID-19 vaccines are both mRNA vaccines.

mRNA vaccines teach your body how to make a protein that will trigger an immune response, without using a live virus.

After you get an mRNA vaccine, your body makes antibodies that help fight the infection if a virus enters your body in the future.

Researchers have been studying and working with mRNA vaccines for decades.

How COVID-19 mRNA vaccines work

The surface of the virus that causes COVID-19 is studded with proteins known as "spike proteins". The virus uses these spikes to enter human cells, infecting you with COVID-19.

mRNA COVID-19 vaccines contain the instructions for making this spike protein.

After you get your vaccine, your immune system recognises that the protein doesn't belong there. Your body then begins building an immune response to fight off what it thinks is an infection. This immune response makes antibodies.

The antibodies offer you protection from COVID-19. It is much safer for your immune system to learn how to protect you from COVID-19 through vaccination than by catching the virus.

Your cells then break down the instructions for making the spike protein and gets rid of them from your body.

Viral vector vaccines

The AstraZeneca and Janssen COVID-19 vaccines are both viral vector vaccines.

Viral vector vaccines use a harmless virus as a delivery system. They teach your body how to make a protein that will trigger an immune response.

Hundreds of scientific studies of viral vector vaccines have been done and published around the world. Some vaccines recently used for Ebola outbreaks have used viral vector technology. Other studies have focused on viral vector vaccines against Zika, flu, and HIV.

How COVID-19 viral vector vaccines work

Viral vector vaccines are like messengers. They use a weakened version of a different virus (the vector) to deliver instructions to cells in your body.

COVID-19 vaccines use the adenovirus as the vector. Adenovirus is the virus that causes the common cold.

The surface of the virus that causes COVID-19 is studded with proteins known as "spike proteins". The virus uses these spikes to enter human cells, infecting you with COVID-19.

When you get a viral vector vaccine, the vector (adenovirus) enters a cell in your body. It then teaches the cell how to produce the COVID-19 spike protein.

After you get your vaccine, your immune system recognises that the protein doesn't belong there. Your body then begins building an immune response to fight off what it thinks is an infection. This immune response makes antibodies.

The antibodies offer you protection from COVID-19. It is much safer for your immune system to learn how to protect you from COVID-19 through vaccination than by catching the virus.

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Understanding How COVID-19 Vaccines Work

Vaccine sticker and vial

What You Need to Know

  • COVID-19 vaccines are safe and effective.
  • You may have side effects after vaccination, but these are normal.
  • It typically takes two weeks after you are fully vaccinated for the body to build protection (immunity) against the virus that causes COVID-19.
  • If you are not vaccinated, find a vaccine. Keep taking all precautions until you are fully vaccinated.
  • If you are fully vaccinated you can resume many activities that you did before the pandemic, but you should wear a mask indoors in public if you are in an area of substantial or high transmission to maximize protection from the Delta variant and possibly spreading it to others.

Vaccine sticker and vial

The Immune System—the Body’s Defense Against Infection

To understand how COVID-19 vaccines work, it helps to first look at how our bodies fight illness. When germs, such as the virus that causes COVID-19, invade our bodies, they attack and multiply. This invasion, called an infection, is what causes illness. Our immune system uses several tools to fight infection. Blood contains red cells, which carry oxygen to tissues and organs, and white or immune cells, which fight infection. Different types of white blood cells fight infection in different ways:

  • Macrophages are white blood cells that swallow up and digest germs and dead or dying cells. The macrophages leave behind parts of the invading germs, called “antigens”. The body identifies antigens as dangerous and stimulates antibodies to attack them.
  • B-lymphocytes are defensive white blood cells. They produce antibodies that attack the pieces of the virus left behind by the macrophages.
  • T-lymphocytes are another type of defensive white blood cell. They attack cells in the body that have already been infected.

The first time a person is infected with the virus that causes COVID-19, it can take several days or weeks for their body to make and use all the germ-fighting tools needed to get over the infection. After the infection, the person’s immune system remembers what it learned about how to protect the body against that disease.

The body keeps a few T-lymphocytes, called “memory cells,” that go into action quickly if the body encounters the same virus again. When the familiar antigens are detected, B-lymphocytes produce antibodies to attack them. Experts are still learning how long these memory cells protect a person against the virus that causes COVID-19.

How COVID-19 Vaccines Work

COVID-19 vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness.

COVID vaccine
COVID-19 Vaccine

Different types of vaccines work in different ways to offer protection. But with all types of vaccines, the body is left with a supply of “memory” T-lymphocytes as well as B-lymphocytes that will remember how to fight that virus in the future.

It typically takes a few weeks after vaccination for the body to produce T-lymphocytes and B-lymphocytes. Therefore, it is possible that a person could be infected with the virus that causes COVID-19 just before or just after vaccination and then get sick because the vaccine did not have enough time to provide protection.

Sometimes after vaccination, the process of building immunity can cause symptoms, such as fever. These symptoms are normal and are signs that the body is building immunity.

Types of Vaccines

Currently, there are three main types of COVID-19 vaccines that are authorized and recommended or undergoing large-scale (Phase 3) clinical trials in the United States.

Below is a description of how each type of vaccine prompts our bodies to recognize and protect us from the virus that causes COVID-19. None of these vaccines can give you COVID-19.

  • mRNA vaccinescontain material from the virus that causes COVID-19 that gives our cells instructions for how to make a harmless protein that is unique to the virus. After our cells make copies of the protein, they destroy the genetic material from the vaccine. Our bodies recognize that the protein should not be there and build T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes COVID-19 if we are infected in the future.
  • Protein subunit vaccines include harmless pieces (proteins) of the virus that causes COVID-19 instead of the entire germ. Once vaccinated, our bodies recognize that the protein should not be there and build T-lymphocytes and antibodies that will remember how to fight the virus that causes COVID-19 if we are infected in the future.
  • Vector vaccines contain a modified version of a different virus than the one that causes COVID-19. Inside the shell of the modified virus, there is material from the virus that causes COVID-19. This is called a “viral vector.” Once the viral vector is inside our cells, the genetic material gives cells instructions to make a protein that is unique to the virus that causes COVID-19. Using these instructions, our cells make copies of the protein. This prompts our bodies to build T-lymphocytes and B-lymphocytes that will remember how to fight that virus if we are infected in the future.

Some COVID-19 Vaccines Require More Than One Shot

vaccines
COVID-19 vaccines

To be fully vaccinated, you will need two shots of some COVID-19 vaccines.

  • Two shots: If you get a COVID-19 vaccine that requires two shots, you are considered fully vaccinated two weeks after your second shot. Pfizer-BioNTech and Moderna COVID-19 vaccines require two shots.
  • One Shot: If you get a COVID-19 vaccine that requires one shot, you are considered fully vaccinated two weeks after your shot. Johnson & Johnson’s Janssen COVID-19 vaccine only requires one shot.

If it has been less than two weeks since your shot, or if you still need to get your second shot, you are NOT fully protected. Keep taking steps to protect yourself and others until you are fully vaccinated (two weeks after your final shot).

Vaccines are now widely available. In many cases, you do not need an appointment. Ninety percent of people in the United States live within five miles of a COVID-19 vaccine location.

Learn how to find a COVID-19 vaccine so you can get it as soon as you can.

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How Corona Vaccine Works (with video) Vaccine Mechanism of Action

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