Dr. Peter Marks, director of the United States Food and Drug Administration’s Center for Biologics Evaluation and Research, said on Thursday that current wisdom about boosters for Covid-19 vaccines suggests that they will be needed, but exactly when is not yet known.
Participants in original vaccine trials are currently being followed so that their immune response can be looked at over time and there is some evidence that it does “fall off somewhat” over time, Marks said during a Covid-19 Vaccine Education and Equity Project webinar.
“The exact timing of when boosters will be required will probably be a combination of two things,” he said. “One, how fast that immune response falls off, but also it may depend on what variants of Covid-19 are circulating.”
He explained that this is because certain levels of immunity are sufficient to prevent Covid-19 with the original strain of the virus, but they may not be good enough for other variants.
“We’ll have to see where this all interacts. Is it possible we’re going to need a booster at some point? Yes. Is it probable? Yes. Do we know exactly when? No,” said Marks. “But if I had to look at my crystal ball, it’s probably not sooner hopefully than a year after being vaccinated for the average adult.”
He added that it may be different for some populations, such as the immunocompromised or older adults, who may need one sooner, but “we’ll just have to see.”
“The good news is it may turn out that the immunity lasts longer,” he said. “Someone who might have looked at the New York Times today might have seen that there’s an article on the longevity of immunity to Covid-19, but I think our wisdom is, current wisdom is that we probably will need boosters at some point.”