The UK, the first country to approve a coronavirus vaccine in late 2020, has now also given the first green light to a variant-adapted vaccine that targets both the original version of the virus and Omicron.
Britain’s medicines regulator (MHRA) on Monday gave conditional approval to a so-called bivalent vaccine made by US pharmaceutical company Moderna as a booster for adults.
Later on Monday, the UK’s Joint Committee on Vaccination and Immunization (JCVI) backed the use of a vaccine adapted to the variant in a revaccination campaign that has been underway in the country since September.
The MHRA Moderna’s decision was based on clinical trial data that showed the booster elicited a “robust immune response” against both Omicron (BA.1) and the original virus, it said.
Moderna said in June that trial data showed that when given as a fourth dose, the variant-adapted injection raised the level of virus-neutralizing antibodies against Omicron eightfold.
The MHRA also cited a research analysis that found the vaccine produced a “good immune response” against the currently dominant Omicron BA.4 and BA.5 branches.
According to Moderna, test data showed that its variant-adapted booster produced levels of virus-neutralizing antibodies against the subvariants that were 1.69 times higher than those who received the original booster.
However, the correlation between the level of neutralizing antibodies and the effectiveness of the vaccine against the disease – especially severe – remains unclear.
No serious safety concerns have been identified with Moderna’s new formulation, the MHRA added on Monday.
Although existing vaccines against COVID-19 still provide good protection against hospitalization and death, the effectiveness of the vaccines has declined greatly as the virus has evolved.
“What this bivalent vaccine gives us is a refined tool in our arsenal to help protect us against this disease as the virus continues to evolve,” MHRA director general June Raine said in a statement.
However, the virus is unlikely to stay put, and immunity targeting Omicron could push the virus down other evolutionary paths, added Jonathan Ball, professor of molecular virology at the University of Nottingham.
“Then we’ll be like the Red Queen in Alice and the Looking Glass – forced to keep running to stay in the same place.”
European Medicines Agency (EMA) officials expect vaccines adapted to the COVID variants to be approved in the European Union by September, and said the regulator is open to using shots targeting the older BA.1 variant this fall, given that vaccines aimed specifically at new subvariants further lag in clinical development.
In contrast, the US Food and Drug Administration (FDA) has said it will push for the inclusion of the newer branches of Omicron BA.4 and BA.5 in any new injections used domestically.
On Monday, the head of the Serum Institute of India, which makes AstraZeneca’s COVID-19 vaccine under the brand name Covishield, said it expects the Omicron vaccine in the country in six months, NDTV reported.
Moderna, which earlier this year signed a £1 billion ($1.2 billion) deal with the British government to build the country’s first mRNA vaccine manufacturing facility, said on Monday it expects further approvals for the adapted vaccine in Australia, Canada and EU in the coming weeks.
Pfizer Inc and BioNTech are also testing versions of their mRNA vaccine modified to fight the Omicron variants.