There are articles regarding SARS-CoV-2 reinfection as the immunity against the virus does not last forever. Will the immunity last longer for vaccinated individuals in comparison to those who have recovered from disease and noted to have immunity?

As we arrive at the one-year anniversary of the first known cases of COVID-19 caused by the novel SARS-CoV-2 virus, we have learned much about the virus and disease.  On the other hand, we also have much vital information yet to be understood regarding how long immunity will last post infection with the SARS-CoV-2 virus compared to immunity after vaccination with the mRNA vaccines. These two vaccines, recently issued Emergency Use Authorizations (EUA) by the US Food and Drug Administration (FDA), are produced by Pfizer-BioNTech and Moderna. Seasonal coronaviruses have been long known to cause approximately 15% of the annual cases of the common cold. We have seen the protection from reinfection to seasonal coronaviruses to last one to two years, with some individuals being reinfected in a matter of months1.  Since the discovery of the SARS-CoV-2 virus approximately one year ago, infrequent reinfections after initial infection have been documented2. Preliminary evidence appears to suggest those who had severe disease are likely to develop greater protection from future re-infection as compared to those who had mild or asymptomatic disease. While reinfections are few in number, they create substantial concerns3.

These two mRNA COVID-19 vaccines elicit an immune response by introducing the genetic material, messenger RNA, which codes for a spike protein found on the surface of the coronavirus that causes COVID-19 disease. In their submissions to the FDA, the manufacturers reported approximately a 95 percent efficacy rate based on Phase 3 clinical trials. More than 30,000 ethnically diverse individuals worldwide, participated in the trials4,5. Currently the CDC notes that reinfection with the SARS-CoV-2 virus is unlikely to occur within the first 90 days after a documented infection.  As a result, the CDC does not recommend quarantine after a close contact for those with a documented infection with the SARS-CoV-2 virus within the first 90 days post-infection, unless the exposed person develops symptoms consistent with COVID-196.  Additionally, the CDC currently recommends vaccination for those previously infected with the SARS-CoV-2 virus3

Although correlates of protection against SARS-CoV-2 infection in humans are not yet established, the results from the clinical trials indicate that there is potential to provide durable humoral immunity. Longitudinal vaccine responses are critically important, and a follow-up analysis to assess safety and immunogenicity in the participants for a period of 13 months is ongoing7. Indeed, both natural and vaccine-induced immunity are likely to play a role in limiting the spread of COVID-19 and its associated mortality8.

In summary, currently, natural immunity after infection with the SARS-CoV-2 virus is estimated to last ~ at 90 days or slightly longer9. The mRNA vaccine trials outcomes are still being evaluated. As the population continues to be vaccinated, the outcomes as regards immunity from the vaccine will also be evaluated as well. Predictions of the burden of illness due to COVID-19 are sensitive to the assumed duration of immunity, currently unknown8. Only time will definitely  tell the answer to this question, but we seem to be leaning towards immunity from mRNA vaccination being the longer lasting.


  1. Sariol A, Perlman S, Lessons for COVID-19 Immunity from Other Coronavirus Infections; Immunity 53, August 18, 2020; page 252. Accessed December 24, 2020 at:
  2. Iwasaki A. Comment, What Reinfections Mean for COVID-19; The Lancet; October 12, 2020; Vol. 21; Issue 1; pages 3-5; Accessed December 24, 2020 at:
  3. CDC. Common Investigation Protocol for Investigating Suspected SARS-CoV-2 Reinfection, Updated October 27, 2020; Accessed December 24, 2020 at:
  4. Fact Sheet for Recipients and Caregivers Emergency Use Authorization (EUA) of the Modera COVID-10 Vaccine to prevent Coronavirus Disease 2019 (COVID-19) in individuals 18 years of age or older. Accessed at: December 23rd, 2020
  5. Fact Sheet for Recipients and Caregivers Emergency Use Authorization (EUA) of the PFIZER-BIONTECH COVID-19 Vaccine to prevent Coronavirus Disease 2019 (COVID-19) in individuals 16 years of age or older. Accessed at: On December 20th, 2020
  6. CDC. COVID-19. When to Quarantine, Updated December 10, 2020, Accessed at:, On December 24th, 2020
  7. Widge A. Durability of Responses after SARS-CoV-2 mRNA-1273 Vaccination. NEJM. December 3, 2020. DOI: 10.1056/NEJMc2032195. Accessed at:, On Dec 24th 2020
  8. Good M, Hawkes M. The Interaction of Natural and Vaccine-Induced Immunity with Social Distancing Predicts the Evolution of the COVID-19 Pandemic. Alan Sher, Editor. DOI: 10.1128/mBio.02617-20. Accessed at:, on Dec 26th 2020
  9. Wajnberg, A., Amanat, F., Firpo, A., Altman, D. R., Bailey, M. J., Mansour, M., ... & Stadlbauer, D. (2020). Robust neutralizing antibodies to SARS-CoV-2 infection persist for months. Science, 370(6521), 1227-1230.

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