Britain, the first country to approve a coronavirus vaccine in late 2020, has now also given the first green light to a variant-adapted shot that targets both the original and Omicron version of the virus.
The UK medicines regulator (MHRA) gave the so-called bivalent vaccine made by U.S. drug company Moderna conditional approval as a booster for adults on Monday.
Britain’s Joint Committee on Vaccination and Immunisation (JCVI) is now expected to issue a recommendation soon on how the vaccine should be deployed in the country.
The MHRA’s decision was based on clinical trial data that showed the booster triggered “a strong immune response” against both Omicron (BA.1) and the original 2020 virus, it said.
Moderna in June said trial data showed that when given as a fourth dose, the variant-adapted shot raised virus-neutralizing antibodies by eight-fold against Omicron.
The MHRA also cited an exploratory analysis in which the shot was found to generate a “good immune response” against the currently dominant Omicron offshoots BA.4 and BA.5.
According to Moderna, trial data showed its variant-adapted booster generated virus-neutralizing antibody levels against the subvariants that were 1.69 times higher than those given the original booster.
However, the correlation between neutralizing antibody levels and vaccine effectiveness against disease – in particular severe disease – remains unclear.
No serious safety concerns were identified with the new Moderna formulation, the MHRA added on Monday.
The UK government said last month a vaccine booster programme would begin in “early autumn” and that shots would offered to over 50s, individuals in clinical risk groups, frontline workers and care homes staff.
While existing COVID-19 vaccines continue to provide good protection against hospitalisation and death, vaccine effectiveness has taken a hit as the virus has evolved.
“The first generation of COVID-19 vaccines being used in the UK continue to provide important protection against the disease and save lives,” MHRA Chief Executive June Raine said in a statement.
“What this bivalent vaccine gives us is a sharpened tool in our armoury to help protect us against this disease as the virus continues to evolve.”
The UK Health and Security Agency (UKHSA), which oversees vaccine procurement among other responsibilities, did not immediately respond to a request for comment.
