Researchers also believe that those who had COVID-19 and then were vaccinated with Pfizer or Moderna’s formulas may be protected for the rest of their lifetimes.
A person getting vaccinated
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Pfizer and Moderna's COVID-19 vaccines may protect against the virus for years, a new study found.

Lingering questions surrounding the COVID vaccines have been about how long the protection will last, and if people will need booster shots to keep it going. But this new research indicates that boosters likely won't be needed - barring the emergence of variants that are stronger than the two mRNA vaccines.

Researchers at the Washington University School of Medicine found that the vaccines create a constant immune reaction in the body that protects it against COVID-19. Looking at the cells in the lymph nodes of people who have been vaccinated, researchers determined that the cells are continually practicing how to fight against the virus, even 15 weeks after the first dose.

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"The fact that the reactions continued for almost four months after vaccination - that's a very, very good sign," Dr. Ali Ellebedy, an immunologist at Washington University in St. Louis and lead author of the study, told The New York Times. Typically, those reactions hit their peak in the week or two after vaccination before starting to die down, but that hasn't been the case with the mRNA vaccines.

"It's a good sign for how durable our immunity is from this vaccine," Ellebedy said.

Researchers also believe that those who had COVID-19 and then were vaccinated with Pfizer or Moderna's formulations may be protected for the rest of their lifetimes, adding to the reasons why it is still necessary for people who had the virus to get vaccinated.

The study, published in the journal Nature, did not look at Johnson & Johnson's vaccine, but Ellebedy expects that the protection may not last as long because it is not an mRNA vaccine.

The key now to reducing the chance that people will need to get booster shots is to stop COVID-19 from spreading and creating new mutations that could evade the vaccines, health experts say.

"Viruses don't mutate if they don't replicate," Dr. Anthony Fauci, the nation's top infectious diseases expert, said last week. "If you give them the opportunity to replicate by allowing them to spread from person to person, you're giving them the perfect opportunity to mutate even more and perhaps evade the vaccine."

It's "another important reason why we need to get vaccinated," he said.

As of June 28, more than half of the U.S. population, or 54% of Americans, have received at least one dose of a COVID-19 vaccine and 46.1% are fully vaccinated, according to the Centers for Disease Control. Of the vaccine-eligible Americans, meaning those aged 12 and up, 63.1% have received at least one dose and 53.9% are fully vaccinated.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDCWHO, and their local public health department as resources.

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