When Will We Need COVID-19 Vaccine Boosters? Here's What We Know So Far.

This is how the coronavirus variants, immunity and other factors will play a role in new shots — and when to expect them.
Scientists are studying booster COVID-19 shots that could protect against emerging variants.
HRAUN via Getty Images
Scientists are studying booster COVID-19 shots that could protect against emerging variants.

The COVID-19 vaccination rollout is well underway in the United States. Millions of people have already been vaccinated. Though experts are hopeful that we’ll reach herd immunity eventually, there are still questions about the need for booster shots and how long our current immunizations will last.

According to health experts, this largely depends on a couple of factors: how long the vaccines guarantee immunity from infection and if emerging variants reduce the efficacy of the vaccine.

Here’s what to know:

Boosters may be needed within 12 months of vaccination, but the definitive timeline is still TBD.

In an early April interview with CNBC, Pfizer CEO Albert Bourla said people will likely need a third COVID-19 shot within 12 months of getting fully vaccinated. Both Pfizer and Moderna are currently working on booster doses.

Data shows both vaccines are still incredibly effective at protecting against COVID-19 for at least six months, but we don’t know how long protection lasts beyond six months because that data hasn’t been collected yet. That is one significant factor in determining when or whether we’ll need boosters (more on that in a moment). The other is the emergence of new variants.

Variants are why it’s so important to get the population vaccinated as quickly as possible. Waleed Javaid, director of infection prevention and control at Mount Sinai Downtown Network in Manhattan, told HuffPost that the faster we get the population vaccinated, the fewer opportunities the virus has to circulate and mutate. Mutations are what lead to more contagious variants, which fuels the need for updated vaccines.

The current COVID-19 variants ― such as the B.1.1.7 variant discovered in Britain, the variant P.1 found in Brazil and the B.1.351 strain uncovered in South Africa ― are more transmissible. However, the vaccines have so far proved somewhat efficacious against the variants. The shots may not be as strong against the current new strains, but they’re not useless by any means.

“We have not seen any variants evade the vaccination completely,” Javaid said.

Experts mostly define vaccine efficacy as preventing severe infection, hospitalization and death. While mild infections can occur after vaccination, that’s not the main cause for alarm.

Jennifer Lighter, infectious disease specialist and hospital epidemiologist at New York University Langone Health, likened the symptoms to a common cold or mild flu. “All of the vaccines prevent hospitalization and death: That’s the bottom line,” Lighter said.

Scientists are still measuring how long the current COVID-19 vaccines offer immunity.

As mentioned above, we don’t yet know how long the vaccines guarantee immunity against the coronavirus. They’re still pretty effective after six months. Right now we use antibody testing as a marker of an immune response. But we need more time to pass to study the population’s response to the vaccines before being able to sufficiently assess the duration of immunity.

Bourla noted that it’s possible we’ll have to get vaccinated for COVID-19 annually.

It’s still unclear how long we’ll be protected from a COVID-19 infection. Once scientists understand how long immunity lasts, we may have a better idea about boosters.
Chalffy via Getty Images
It’s still unclear how long we’ll be protected from a COVID-19 infection. Once scientists understand how long immunity lasts, we may have a better idea about boosters.

Making a booster shot won’t take as long as the original vaccines.

With the Moderna and Pfizer shots, vaccine makers are able to update existing vaccines to address new strains. This process typically takes about three months.

The Johnson & Johnson vaccine uses an adenovirus ― part of the common cold ― to send a message to the body’s cells and trigger an immune response against the coronavirus that causes COVID-19. J&J’s vaccine trials occurred when some of the new variants were circulating, so experts aren’t concerned about its efficacy when it comes to hospitalization or death. The company’s CEO told CNBC in early March that it is working on software that will address the new and emerging variants should that be needed, but he didn’t offer many other details about what that software might be.

COVID-19 likely won’t disappear completely.

There has been somewhat of a vaccine response against known COVID-19 variants so far, but Lighter noted that the virus will likely continue to mutate.

“COVID-19 isn’t going away,” she said. “Looking long-term, it’s going to feel like the flu. The flu mutates every year, we have to have a vaccine every year, but it’s totally manageable because there are treatments and vaccines and people have immunity.”

Right now, we don’t know if or exactly when we’ll need adjustments to the vaccine, in the form of boosters, to target ongoing variants. But given the fact that we will continue to see new mutations, it’s likely we’ll need to get COVID-19 vaccines for some time to come.

Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.