Reuters :
Pfizer Inc plans to ask US regulators to authorize a booster dose of its Covid-19 vaccine within the next month, the drugmaker’s top scientist said on Thursday, based on evidence of greater risk of reinfection six months after inoculation and the spread of the highly contagious Delta variant. The US Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) said, however, in a joint statement that Americans who have been fully vaccinated do not need a booster Covid-19 shot at this time.
Some scientists have also questioned the need for booster shots.
Pfizer’s chief scientific officer, Mikael Dolsten, said the recently reported dip in the vaccine’s effectiveness in Israel was mostly due to infections in people who had been vaccinated in January or February. The country’s health ministry said vaccine effectiveness in preventing both infection and symptomatic disease fell to 64% in June.
“The Pfizer vaccine is highly active against the Delta variant,” Dolsten said in an interview. But after six months, he said, “there likely is the risk of reinfection as antibodies, as predicted, wane.”
Pfizer did not release the full set of Israeli data on Thursday, but said it would be published soon.
“It’s a small data set, but I think the trend is accurate: Six months out, given that Delta is the most contagious variant we have seen, it can cause infections and mild disease,” Dolsten said.
The FDA and CDC, in their joint statement, said: “We are prepared for booster doses if and when the science demonstrates that they are needed.”
