Pfizer Looks to Authorize Booster Vaccine Dose as Antibodies ‘wane,’ Delta Variant Spreads

Pfizer Inc’s top scientist said on Thursday the drugmaker will be asking U.S. regulators to authorize a booster dose of its COVID-19 vaccine within the next month. “The Pfizer vaccine is highly active against the Delta variant,” said Pfizer Chief Scientific Officer Mikael Dolsten.

However, after six months “there likely is the risk of reinfection as antibodies, as predicted, wane” he said. Dolsten said the recently reported decrease of vaccine efficacy 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, reported Reuters. Dolsten said Pfizer did not release the full set of Israeli data on Thursday but will publish it 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,” said Dolsten. He also added Pfizer’s data from the United States also shows a decline in the vaccine’s effectiveness to the mid-80s after six months.

Dolsten did stress that data from Israel and Britain still suggest that even with waning antibody levels, the vaccine remains around 95% effective against “severe disease.”

Reuters reports:

The vaccine, developed with German partner BioNTech SE, showed 95% efficacy in preventing symptomatic COVID-19 in a clinical trial the companies ran last year.

Dolsten said that early data from the company’s own studies shows that a third booster dose generates antibody levels that are five to 10-fold higher than after the second dose, suggesting that a third dose will offer promising protection.

He said multiple countries in Europe and elsewhere have already approached Pfizer to discuss booster doses, and that some may begin administering them before a potential U.S. authorization.

Dolsten said he believes that booster shots are particularly important in older age groups.

Pfizer has previously said individuals will likely need a booster dose. “But some scientists have questioned when, or whether, they will be needed” writes Reuters. Pfizer and BioNTech are also designing a new version to target the Delta variant, but Dolsten said the companies do not believe that the current version will need to be replaced in order to combat the variant.