US drug maker Pfizer has announced that it has submitted an application to the US Food and Drug Administration (FDA) for emergency use authorization (EUA) of an additional booster dose for adults 65 years of age and older who have received an initial booster of any of the authorized or approved Covid-19 vaccines.
The submission is based on two real-world data sets from Israel analyzed at a time when the Omicron variant was widely circulating. Both data sets showed evidence that an additional mRNA booster increases immunogenicity and lowers rates of confirmed infections and severe illness.
The Pfizer-BioNTech Covid-19 vaccine is currently authorised as a single booster dose administered at least five months after completion of a primary series of the Pfizer-BioNTech Covid-19 vaccine to individuals 12 years of age and older.
In a statement, Pfizer and BioNTech said an additional dose of their vaccine at least four months after a third shot could restore levels of virus-blocking antibodies and has been shown to protect adults 60 and older against severe illness and infections. They also added that “people who are vaccinated, particularly those who have received a booster, maintain a high level of protection, particularly against severe disease and hospitalisation”, Washington Post reported.
Albert Bourla, Chief Executive of Pfizer, said at a Washington Post Live event last week that a fourth shot would be needed because immunity wanes.
“We are working right now very intensively,” Bourla said, adding: “I think our data suggests that (fourth doses) are protecting – they are improving dramatically the protection, the fourth dose compared to the third for Omicron after some time, after, let’s say, three to six months.”
On CBS’s “Face the Nation”, he said that the protection provided by the first booster is “actually quite good for hospitalisations and deaths. It’s not that good against infections.” Pfizer is also working on a vaccine targeting all variants and aimed at providing protection for at least a year.