US approves Omicron vaccines from Moderna and BioNTech/Pfizer

US drug regulators have approved applications by Moderna and BioNTech/Pfizer to release a Covid-19 vaccine that specifically targets the dominant strain of the Omicron variant.

The Food and Drug Administration on Wednesday gave the companies the go-ahead to roll out their “bivalent” shots, which target both the original strain of Covid and the fast-spreading BA.4 and BA.5 subvariants, ahead of a national booster programme this autumn.

US officials had previously resisted pushing ahead with variant-specific vaccines, but have been persuaded by the fact that many people with two or more shots are still susceptible to infection. They have taken this next step with the new vaccines despite a lack of clinical evidence about how they will work in an attempt to head off a huge spike in infections this winter.

Robert Califf, head of the FDA, said in a statement that the regulator strongly encouraged anyone eligible “to consider receiving a booster dose with a bivalent Covid-19 vaccine to provide better protection against currently circulating variants”.

Biden administration officials put great stock in the original generation of Covid vaccines, promising a return to normality soon after taking office.

But case numbers and deaths have remained stubbornly high since then, in part because recent variants have proved better able to evade the vaccines. The US Covid death toll since the start of the pandemic passed 1mn earlier this summer, and the country continues to report almost 400 deaths and more than 5,000 new hospitalisations linked to coronavirus every day.

Officials are particularly worried about what will happen this winter when people begin to socialise indoors more, in many cases without masks or other mitigation measures.

The two bivalent vaccines were approved despite the companies not having conducted human trials into whether they work or are safe.

Instead, officials relied on data from a previous bivalent vaccine, which was made by BioNTech/Pfizer and combined the original strain with the BA.1 subvariant. They found that shot provoked a better immune response in trial participants and did not trigger any safety concerns.

The FDA insisted it was confident the new vaccines would prove both safe and effective enough to prevent the kind of peak in cases seen last winter. The original vaccines will no longer be offered as booster shots.

In contrast, EU regulators have said they want to review clinical data before authorising the latest generation of Covid boosters.

“We have to try to be a step ahead because if we waited for all the proof to come in, the wave will have already passed us by and the damage will have been done,” Califf said.

Peter Marks, head of the unit that authorises vaccines at the FDA, said: “The hope here is that by increasing the amount of antibodies we have to that particular variant, we will restore the kind of protection that we had when we first saw these vaccines launched in the late part of 2020, early part of 2021, where we had very good protection against symptomatic disease.

“We don’t know for a fact yet whether we will get to that same level, but that is the goal here.”

The Moderna shot is authorised for anyone aged 18 and over, while the BioNTech/Pfizer vaccine can be given to anyone aged 12 or over. The vaccines are designed to be administered as a single booster at least two months after a previous jab.