Covid-19 pandemic: Pfizer seeks US regulator's nod for booster shot

FDA and EU regulator say no need for extra dosage at this time

Pfizer and partner BioNTech plan to ask US and European regulators within weeks to authorise a booster dose of its Covid-19 vaccine, based on evidence of greater risk of infection 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 shot at this time.

The European Medicines Agency (EMA), too, said it was early to determine whether more than the two shots that are currently required would be called for, saying it was confident for now that the established regimen was sufficient.

The World Health Organization (WHO) has said it is not clear whether booster vaccines shots be useful to maintain protection against the virus. 

“We don’t know whether booster vaccines will be needed to maintain protection against Covid-19 until additional data is collected, but the question is under consideration by researchers,” the global agency said in a reply to a Reuters query.

On the other hand, 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 the beginning of this year. Israel’s health ministry said vaccine effectiveness in preventing both infection and symptomatic disease fell to 64 per cent in June. 

“The Pfizer vaccine is highly active against the Delta variant,” Dolsten said. But after six months, he said, “there likely is the risk of reinfection as antibodies, as predicted, wane.” The data would be submitted to the FDA within the next month.