Pfizer seeks US FDA authorisation for fourth Covid-19 vaccine shot for seniors

WASHINGTON (BLOOMBERG) - Pfizer says it has asked US regulators for clearance of an additional Covid-19 booster shot for seniors, in a bid to protect vulnerable adults as immunity provided by the first three doses wanes.

The New York-based drugmaker and its German partner BioNTech SE said they have sought an emergency use authorisation from the Food and Drug Administration (FDA) for a second booster of their vaccine, Comirnaty, for people aged 65 and older who have already received a booster of any of the authorised Covid-19 vaccines.

Last year, the FDA granted a full approval for the initial two-dose regimen and cleared a third-dose booster.

Pfizer and BioNTech said they submitted to the FDA data from Israel, which began offering a fourth shot to older people and healthcare workers last year.

The real-world data showed that a fourth shot at least four months after the third reduced the rate of infection and severe illness, according to an analysis of Israeli Ministry of Health records for more than 1.1 million adults aged 60 and older.

In an interview with Bloomberg Television last week, Pfizer chief executive officer Albert Bourla said the company would soon submit data on a fourth dose of its vaccine to the FDA.

He said the data "looks encouraging" but was not complete. He did not say precisely what data he had been reviewing.

On Sunday (March 13), Dr Bourla said in an interview with CBS that a fourth dose of the vaccine was needed "right now" as protection from the first three shots had waned.

The Washington Post reported on Tuesday that Pfizer and BioNTech could file for an emergency use authorisation imminently.

People who received a third dose generally fared better against the Delta and Omicron variants than people who received only two doses, according to studies that the Centres for Disease Control and Prevention (CDC) released earlier this year.

While Covid-19 cases have dropped sharply from their winter peak, there are signs that another increase in infections could be on the cards in the coming weeks.

More than a third of CDC wastewater sample sites in the United States showed rising virus trends earlier this month.

Pfizer is also studying an Omicron-specific vaccine and a hybrid shot that would target Omicron along with earlier variants.

The company is expected to report data on these efforts in April. The CDC recommends some immunocompromised people get a three-dose primary series of mRNA shots and a fourth shot as a booster.