By three months the booster only reduces the risk of a symptomatic infection by about 50%.
"That is perfectly normal and expected," she says, "So in terms of protection against infection, we will see some protection early on with a booster, but that protection is going to wane.
On the other hand, she says, protection against severe disease doesn't depend so heavily on antibodies.found that the booster offers more robust protection against severe disease than against infection.
Specifically, the researchers found that, after a third shot of Pfizer, protection against hospitalizations starts out above 95% (two weeks after the shot) and remains at around 80% even after four months.
By comparison, with only two shots of any vaccine, protection against severe disease declines to 40% after six months.