Though experts are hopeful that we’ll reach herd immunity by the fall if vaccinations continue at our current pace, there are 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 aren’t a reality yet, but they might be down the road.
At this point, the conversation on the need for booster shots for COVID-19 is still slightly hypothetical, although vaccine manufacturers and researchers are already preparing for the possibility by testing boosters and vaccines adjusting for known coronavirus variants.
“Currently the most important thing right now is to get people vaccinated,” said Waleed Javaid, director of infection prevention and control at Mount Sinai Downtown Network in Manhattan.
Javaid explained that the quicker we get the population vaccinated, the fewer opportunities the virus has to circulate and mutate. Mutations are what lead to more contagious variants, which could potentially call for an updated vaccine down the line.
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 and could lead to a fourth wave of cases.
However, so far the vaccines have 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.
We also don’t yet know how long the vaccines guarantee immunity against the coronavirus. TD (tetanus and diphtheria) shots, for example, require a booster every 10 years. If we start to see new cases of COVID-19 emerging in the population anywhere between six months to five years from now, then that would be a good reason for a booster, Javaid said.
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.
Making a booster shot, if and when we need it, won’t take as long as the original vaccines.
With the Moderna and Pfizer-BioNTech shots, vaccine makers are able to update existing vaccines to address new strains. Typically, this process takes about three months. Both companies are already testing a booster shot and working on a shot that targets COVID-19 mutations but haven’t committed to when or if they’ll be needed for the public.
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.
Though there has been somewhat of a vaccine response against known COVID-19 variants so far, 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 that scientists will eventually need to create updated shots to provide protection against subsequent virus strains. Whether that’s after six months, a year or five years is the question.
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.