EU regulator backs Pfizer's Omicron-adapted vaccine booster

The European Medicines Agency (EMA) on Monday recommended a COVID-19 booster designed to combat Omicron offshoots BA.4/5.

It comes just days after endorsing a pair of boosters tailored to target the older BA.1 variant.

The latest recommendation is for a so-called bivalent vaccine developed by Pfizer and BioNTech, which targets BA.4/5 as well as the strain of the virus that originally emerged in China in December 2019.

The EMA recommendation is to authorize the vaccines for people aged 12 and above who have received at least primary vaccination against COVID.

The final go-ahead will be subject to European Commission approval, which is expected to come in shortly.

If authorized, the BA.4/5-tailored booster will be available in days to all 27 EU member states, Pfizer said in a statement on Monday.

While existing coronavirus vaccines provide good protection against hospitalization and death, their effectiveness was reduced as the virus evolved.

Earlier this month, the EMA endorsed both Pfizer-BioNTech and Moderna's MRNA.O BA.1 updated vaccines.

EU officials signalled in recent months they were open to initially using shots targeting the older BA.1 variant, given those specifically targeting newer Omicron offshoots BA.4/5 are further behind in development.

In contrast, the US Food and Drug Administration (FDA) insisted it was only interested in vaccines targeting BA.4/5.

Last week, Pfizer-BioNTech and Moderna secured US approval for those.

Given BA.1 emerged first, data from human trials testing the adapted vaccines from sets of developers has been submitted to EU regulators.

For the BA.4/5 adapted vaccines, regulatory submissions are largely based on lab and animal data.

Using animal and lab data to solicit regulatory approval for retooled vaccines is not without precedent - it is done regularly for flu vaccines that are revamped each year to combat new variants.

On Monday, the EMA said its backing of the Pfizer-BioNTech updated BA.4/5 shot relied partly on data from human clinical trials available on the companies' BA.1-tailored vaccine.

EU officials have encouraged member states to roll out boosters of the established original vaccines and the bivalent shots - whatever is readily available - this autumn/winter initially for the vulnerable and elderly, following a rise in infections over the summer as protection waned due to the domination of BA.4/BA.5.

But uptake of the updated vaccines could be limited, as people have become less worried about the disease, thanks in large part to the success of first generation of shots.