How Long Does COVID-19 Vaccine Immunity Last?

What we know about immunity after vaccination, booster shots, and protection against new variants.

Clinical trials and real-world conditions have proved that vaccines protect against COVID-19. But the question remains: How long will vaccine immunity last?

In light of the Omicron variant — now the most dominant variant in the United States — the Centers for Disease Control and Prevention (CDC) strongly recommends everyone 5 years and older get vaccinated. And if it has been five months since your last Pfizer or Moderna vaccine or two months since your Johnson & Johnson vaccine, getting a booster shot is recommended for those 12 and older.

Dr. Sharon Chacko

Dr. Sharon Chacko

To learn more about this evolving issue, Health Matters spoke with Dr. Sharon Chacko, medical director of COVID-19 immunizations in the Division of Community and Population Health and an assistant professor of medicine at Columbia University Vagelos College of Physicians and Surgeons, about vaccine immunity and the recommendation for booster shots amid Omicron.

Health Matters: What do we know about how long immunity lasts after vaccination for COVID-19?
Dr. Chacko: We know that vaccines provide strong protection against severe disease, hospitalizations, and death. Health officials continue to monitor data, and with the rise of variants — such as the highly contagious Omicron variant — they are keeping a close eye on breakthrough infections and waning immunity. Because immunity after vaccination may decrease over time, the CDC now recommends boosters for everyone over 12 years old.

The CDC just published data that shows that getting a Pfizer or Moderna booster after completing a primary mRNA COVID-19 vaccine series was 90% effective at preventing hospitalizations when Omicron was the dominant variant. In comparison, getting two shots was 57% effective when it had been at least six months past the second shot. Another large study that was published in the Journal of the American Medical Association (JAMA), showed that a booster shot helped prevent symptomatic infection from Omicron. That study found that the odds of developing a symptomatic infection were 66.3% lower for people who were boosted compared to those who had received only two shots.

With Omicron, many more people have experienced breakthrough infections. Does that mean vaccines aren’t working?
While Omicron is more transmissible and is responsible for more breakthrough infections than any other variant, a breakthrough infection doesn’t mean that the vaccine isn’t working. In fact, for most people who are vaccinated and boosted, the symptoms are typically very mild. This emphasizes the importance of vaccination and boosters to prevent severe illness and hospitalizations.

Will we need boosters annually?
Currently, we don’t know how often boosters will be needed, but researchers are closely monitoring this question.

What do we know for sure?
Here’s what we know:

  • Vaccines are safe and continue to be highly effective at preventing severe illness, hospitalizations, and death.
  • The CDC recommends that everyone 5 years and older protect themselves from COVID-19 by getting fully vaccinated and also recommends booster shots for everyone 12 and older.
  • Adolescents ages 12-17 can receive a Pfizer booster at least 5 months after completing the initial vaccine series.
  • Adults ages 18 and above can receive a booster at least 5 months after completing a Pfizer or Moderna mRNA vaccine series or 2 months after receiving the Janssen/Johnson & Johnson single-dose shot.

One thing we can all do is get vaccinated and encourage the people in our lives to also get vaccinated and boosted. Vaccination provides individual immunity, and as more people are vaccinated, we stop the spread of COVID-19, which means fewer opportunities for the virus to mutate, and thus slow the emergence of new variants.

Sharon M. Chacko, M.D., is a family medicine physician and an assistant professor of medicine in the Center for Family and Community Medicine at Columbia University Vagelos College of Physicians and Surgeons. Dr. Chacko has been a medical lead for NewYork-Presbyterians COVID-19 vaccination efforts and served as medical director at the vaccination site established by NewYork-Presbyterian at The Armory. She is now medical director of COVID-19 immunizations in the Division of Community and Population Health.

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