How Long Will COVID-19 Vaccine-Induced Immunity Last?

Older woman receiving a vaccine shot in the arm.

Luis Alvarez / Getty Images

Key Takeaways

  • The Moderna and Pfizer-BioNTech vaccines could offer immunity against COVID-19 for up to two to three years. However, they will most likely have to be administered annually.
  • The vaccines will likely protect against current variants of COVID-19 as well as the original virus itself. 
  • Immunity wanes as antibody levels drop in response to a lack of use.

Since mid-December, Moderna and Pfizer-BioNTech's COVID-19 vaccines have been administered to at least 6.6 million people in the U.S., according to the Centers for Disease Control and Prevention (CDC). Both vaccines offer immunity with about 95% effectiveness. But the exact duration that immunity lasts is still unknown.

Will it last years or months? While experts say that only time—and further research—will tell, some are inclined to believe that COVID-19 vaccinations will be a recurring, rather than a one-off, event. 

What This Means For You

While more research needs to be done, experts believe you may have to receive the COVID-19 vaccine multiple times throughout your life rather than just once. The vaccines may need to be distributed annually.

How Long Will Immunity Last?

It “is very likely that for [the] COVID-19 vaccine, given that the length of immunity the vaccine generates is limited, we may have to be vaccinated annually,” Chunhuei Chi, MPH, director of the Center for Global Health at Oregon State University’s College of Public Health and Human Sciences, tells Verywell.

In this regard, the COVID-19 vaccines currently available are not unusual. Most vaccines, Chi says, “have their specific duration of immunity that can range from a few months to decades.” The flu vaccine, which immunizes against seasonal influenza for several months, represents one end of the spectrum; the measles vaccine, which immunizes against measles for life, represents the other. The magnitude of variation, Chi says, is the result of the unique “combination of characteristics of viruses and vaccines.”

The hope, Jere McBride, PhD, director of the experimental pathology graduate program at the University of Texas Medical Branch, tells Verywell, is that the Moderna and Pfizer-BioNTech vaccines will confer immunity for two to three years. In reality, however, the duration “could be longer or shorter” and will only be determined by conducting studies of people who have received the vaccine.

McBride does not anticipate the discovery of differences in immunity duration between the two vaccines because the two work in similar ways. “The Moderna and Pfizer vaccines should be similar, based on the mRNA approach and the fact that the specific mRNA used to induce immunity is similar,” he says.

Like most vaccines, the COVID-19 vaccines have multiple mechanisms for preventing infection. The first involves the production of antibodies; the second involves the induction of responses in memory B and T cells—immune cells that retain information for future reference.

However, immunity does wane, and when it does it so often varies between individuals based "on how they immunologically respond to a vaccine," McBride says. Like human memory, cellular memory is short. The purpose of a booster shot is to jog it.

Effectiveness Against New Strains

In December 2020, the news that scientists had discovered a new—and possibly more contagious—strain of COVID-19 cast a shadow over the vaccines’ rollout. First identified in southeastern England in September, the new strain has since spread to multiple countries including the U.S.

But McBride says the original and the mutant are similar enough that the vaccines should immunize against both. 

“Although new coronavirus strains emerge, the variation is not as large as that seen with seasonal influenza strains, and whether it affects vaccine efficacy is dependent on where the mutation occurs," he says. "In this case, the vaccine will likely protect against the variant as well."

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Article Sources
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  1. Centers for Disease Control and Prevention. CDC COVID Data Tracker. Updated January 8, 2020.

  2. Centers for Disease Control and Prevention. Measles, mumps, and rubella (MMR) vaccination: what everyone should know. Updated March 28, 2019.

  3. The Immunisation Advisory Centre. The immune system and immunisation. Updated January 2020.

  4. Johns Hopkins University. A new strain of coronavirus: what you should know. December 28, 2020.