There’s little doubt now — study after study, in real life and in lab dishes, in the US and elsewhere — that people’s immunity starts to wane just months after they finish the two-dose series of Pfizer Covid-19 vaccine.
While getting two doses of vaccine creates a strong immune response that reduces the risk of severe disease by more than 90%, the protection against milder and asymptomatic infections drops off gradually.
That’s why Pfizer has asked for and received US Food and Drug Administration authorization to add boosters for many people who are six months out from vaccination.
But should others be seeking boosters, too? How much should people be worrying?
“I think that we expect that immunity will slowly wane, over time, but it’s not a reason for people to panic,” said Dr. Ann Falsey, a specialist in viral respiratory diseases at the University of Rochester School of Medicine.
“It’s not like suddenly one day you’re completely susceptible, like you were before you were vaccinated,” added Falsey, who is helping lead clinical trials of Covid-19 vaccines.
“The vaccines are all standing up pretty well — Pfizer, Moderna and Johnson & Johnson — for severe disease,” Falsey told CNN. “Now, that’s not to say that we might not eventually get to a point where we really need people to get boosters to prevent more severe illness. But, really, the majority of the breakthrough infections are colds, maybe flu-like illness — not the scary illnesses that we were facing before,” she added.
“So my main message is, don’t panic. You’re going to be okay.”