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How long does protection last after a COVID-19 vaccine?

This article was published on
May 6, 2021

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Current research shows that immunity lasts at least about 6 months for mRNA COVID-19 vaccines (the Pfizer vaccine and the Moderna vaccine). Some researchers estimate that immunity against COVID-19 following vaccination will last longer, but because the virus is so new, experts are not sure if protection might wane. More research is needed to better understand how long people will likely be protected after vaccination and how it might vary across different individuals and across different vaccines.

Current research shows that immunity lasts at least about 6 months for mRNA COVID-19 vaccines (the Pfizer vaccine and the Moderna vaccine). Some researchers estimate that immunity against COVID-19 following vaccination will last longer, but because the virus is so new, experts are not sure if protection might wane. More research is needed to better understand how long people will likely be protected after vaccination and how it might vary across different individuals and across different vaccines.

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What our experts say

Some vaccines, such as those for measles, mumps, and rubella, give a person lifetime protection. Others, like the flu vaccine, require a person to get a new shot every year. That's because with some shots, immunity can wane. We’re not sure yet which type of vaccine the COVID-19 vaccines will be, but the best estimate is the mRNA vaccines currently in use (the Pfizer-BioNTech and Moderna vaccines) are likely to last for one to three years, and that most vaccines will need to be recurring.

If “booster” shots are needed, or if the COVID-19 vaccines are needed every year, they should be relatively easy to produce—especially mRNA vaccines in use. 

We don’t know how long vaccines work against COVID-19 yet, because they have not been in use for very long. However, Pfizer-BioNTech said that the ongoing phase three trial of its mRNA vaccine shows that strong protection lasts for at least 6 months for individuals who are vaccinated.

The Pfizer vaccine has 91.3% efficacy against COVID-19 six months after someone gets their second dose. Similarly, evidence for the Moderna vaccine shows 94% effectiveness six months following the second dose.

Importantly, estimates on protection could also change if there are more serious variants that are better at infecting vaccinated people. The vaccines currently in use have been shown to be effective against most, but not all, COVID-19 variants—particularly those circulating in the United States. But as the virus keeps changing naturally, variants could emerge that the vaccines are less effective against.

The promising six-month data is an important and helpful milestone nonetheless. It tells experts the vaccines are working, and that protection will last longer than 6 months. Experts estimate that the Pfizer and Moderna vaccines may provide good protection from COVID-19 for one to three years. Manufacturers will continue to monitor the effectiveness of their vaccines, and Moderna and Pfizer-BioNTech have launched preliminary studies of booster shots.

Right now there is no good data on how long protection against COVID-19 lasts for other vaccines, like the Johnson & Johnson or AstraZeneca vaccines. As that data comes out we will be able to know more about how much other vaccines protect against the virus over time. 

Context and background

COVID-19 vaccines in use are highly effective at preventing COVID-19 infection and severe cases, and early research suggests they should maintain their effectiveness over at least six months. What remains unclear, however, is how long the vaccines will maintain that effectiveness and prevent against COVID-19, if booster shots or new shots may be needed to improve protection, or if vaccines will need to be changed to fight against new variants of the virus.

Resources

  1. Measles, Mumps, and Rubella (MMR) Vaccination: What Everyone Should Know (Centers for Disease Control and Prevention)
  2. Pfizer and BioNTech Confirm High Efficacy and no Serious Safety Concerns Through up to Six Months Following Second Dose in Updated Topline Analysis of Landmark COVID-19 Vaccine Study (Pfizer-BioNTech)
  3. Pfizer and BioNTech Conclude Phase 3 Study of COVID-19 Vaccine Candidate, Meeting all Primary Efficacy Endpoints (Pfizer-BioNTech)
  4. How long does immunity last after COVID-19 vaccination? (GAVI, the Vaccine Alliance)Antibody Persistence through 6 Months after the Second Dose of mRNA-1273 Vaccine for Covid-19 (The New England Journal of Medicine)
  5. Vaccines and Related Biological Products Advisory Committee Meeting December 17, 2020: Moderna COVID-19 Vaccine (Food and Drug Administration)
  6. About Variants of the Virus that Causes COVID-19​​ (Centers for Disease Control and Prevention)
  7. Neutralization of SARS-CoV-2 Variants B.1.429 and B.1.351 (The New England Journal of Medicine)
  8. Neutralization of N501Y mutant SARS-CoV-2 by BNT162b2 vaccine-elicited sera (bioRxiv)
  9. Estimated transmissibility and severity of novel SARS-CoV-2 Variant of Concern 202012/01 in England (medRxiv)
  10. Neutralization of SARS-CoV-2 spike 69/70 deletion, E484K, and N501Y variants by 2 BNT162b2 vaccine-elicited sera (bioRxiv)

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