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July 24, 2021

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How Long Will COVID-19 Vaccines Protect You?

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On behalf of the TeamHealth Emerging Infectious Disease Task Force

As we move into new phases of the pandemic, including virus variants, population vaccine density, COVID fatigue and other issues, one of the concerns is how long any protection from a vaccine lasts. We covered the mounting data on the lack of much lasting immunity, mostly against the new emerging variants, from natural COVID infections in a previous post. However, with many of us approaching the six-month anniversary of our COVID vaccine, how long can we expect our vaccine to protect us?

The Vaccine Research

Both the Pfizer and Moderna mRNA vaccines provide protection for a minimum of six months. And the level of antibody produced at six months was “robust” (reference). Now, a study in Nature suggests that the mRNA vaccines likely provide a level of protection for much longer (reference).

This study was conducted by an NIH-supported research team at Washington University School of Medicine. The team tested specific indicators for long-term immunity in the bone marrow and lymphatic systems of humans who were given the Pfizer mRNA COVID-19 vaccine. They found that after full vaccination with the Pfizer-BioNtech mRNA vaccine the study participants all had markers of a strong, persistent immune response to SARS-CoV-2 that is likely to last for years to come.

This study was VERY well-conducted (and even included bone marrow and lymph node biopsies from the participants), but it had small numbers, so further research is going to be needed. However, this has important implications for those of us at or beyond our six-month mark for the vaccine.

These data, and others also impacted the recent decision by the FDA not to rush into a “booster” shot for the Pfizer vaccine. Currently, it is not evident that a booster is needed. Although the vaccines currently provide excellent protection for the known variants, it may become necessary in the future to change the antigens coded for by the mRNA vaccines to more closely match any future variants.

Data support that the current mRNA vaccines are still highly effective at preventing COVID-19. That’s why it remains so critical that more Americans get vaccinated not only to protect themselves and their loved ones, but to help stop the virus’s spread in their communities and thereby reduce its ability to mutate.

There are some cases of COVID vaccine breakthrough infection and there have been some deaths of vaccinated people. Most vaccines, in general only protect from disease in the 50% to 60% range. But the mRNA COVID-19 vaccines are between 70 to 90% protective in most studies, but NOT 100%. What does that mean for clinicians?

  • Take, finish and promote any of the three COVID-19 vaccines.
  • Be smart. Even if you are fully vaccinated, use an N95 and proper personal protective measures when evaluating high-risk patients in a clinical setting.
  • If the community circulation of SARS-CoV-2 (currently the Delta variant) is high where you work and live (a so-called Hyperlocal Outbreak) – you should use an N95 and proper personal protective measures for all patients in the clinical setting.
  • Even when you are fully vaccinated, if you receive a high enough dose of virus (particularly if that virus is more dangerous and infective like the Delta variant) you can still get it. Although you are unlikely to become severely ill, you can probably spread it to others. Underlying health risk factors pose an additional risk.
References

Turner JS, O’Halloran JA, Kalaidina E, et al. SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responsesNature. 2021 Jun 28. [Online ahead of print]

Turner JS, Kim W, Kalaidina E, et al. SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humansNature. 2021 May 24. [Online ahead of print]

NIH. COVID-19 Research