Pfizer 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.
The announcement was based on evidence of greater risk of reinfection six months after inoculation and due to the spread of the highly contagious Delta variant of coronavirus.
The US pharmaceutical company and its German partner BioNTech have started designing a version of their vaccine specifically to combat the highly contagious Delta variant, Pfizer’s chief scientific officer, Mikael Dolsten, said.
However, the companies do not think they will need to replace the current version of their highly successful shot.
The news comes as US regulators said Americans who have been fully vaccinated do not need a booster Covid-19 shot at this time.
“We are prepared for booster doses if and when the science demonstrates that they are needed,” the US Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) said in a joint statement late on Thursday.
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.