FDA approves Pfizer COVID booster jabs for higher-risk groups

Just days after its advisory committee meeting voted to approve a third dose of Pfizer and BioNTech's COVID-19 vaccine, the FDA has followed through and cleared the shot.

The FDA has amended the emergency use authorisation (EUA) for Comirnaty in line with its experts' advice – for people aged over 65 and other adults at risk of getting severe COVID-19, either because of medical reasons or institutional or occupational exposure to SARS-CoV-2.

The third dose of Comirnaty is to be administered at least six months after completion of the second Comirnaty dose, according to the US regulator.

An agency official said however that boosting would only be available for now to people who received Comirnaty for the first and second doses, as there isn't enough data yet on the effect of mixing different vaccines.

Other countries, including the UK, have set out plans for booster campaigns that include vaccine mixing, with some experts arguing this could improve efficacy.

Pfizer and BioNTech had hoped to get the nod for booster doses in everyone aged 16 or over as it went into the advisory committee meeting last Friday, but that was comprehensively rejected by the panel.

The Biden Administration had previously said it will roll out booster shots for all people aged 16 and older this week, pending approvals from the FDA and Centers for Disease Control and Prevention (CDC). A CDC advisory panel could also vote today on the use of a third shot of Comirnaty.

The amendment to the EUA means that tens of millions of Americans will be in line for a third dose of Comirnaty, a group which – according to FDA acting commissioner Janet Woodcock – will include "healthcare workers, teachers and day care staff, grocery workers and those in homeless shelters or prisons, among others".

It is estimated that around 22 million adults in the US are already beyond the second dose of Comirnaty, with roughly half of those aged over 65, according to CDC data.

As for the other two vaccines used in the US, Moderna's mRNA-1273 – like Comirnaty – has previously been cleared for emergency use as a booster in at-risk people, such as those with weakened immune systems.

Moderna submitted preliminary data on a third dose of its vaccine to the FDA earlier this month, with additional results expected within the next two weeks.

J&J meanwhile reported data earlier this week showing that a second shot of its one-dose vaccine was highly effective, boosting protection against moderate to severe COVID-19 to 94%.

All three vaccines are still effective at preventing hospitalisation for COVID-19, according to real-world data released by the CDC last Friday looking at admissions between March and August of this year.

Moderna was 93% effective at keeping people out of hospital, compared to 88% for Comirnaty and 71% for J&J.