The United Kingdom on Monday became the first country to approve an updated COVID-19 vaccine from Moderna targeting the omicron variant as well as the original strain of the virus.  

The move is a step toward a booster campaign that could provide people with better protection against the variants that are currently circulating. 

“The first generation of COVID-19 vaccines being used in the UK continue to provide important protection against the disease and save lives,” said June Raine, chief executive of the UK’s Medicines and Healthcare products Regulatory Agency. “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 United States is also working on updated vaccines for a possible fall booster campaign, though the shots might be slightly different. The vaccine approved by the UK targets the first version of the omicron variant, known as BA.1, while the U.S. Food and Drug Administration has instructed vaccine makers to target the more recent subvariants of omicron, known as BA.4 and BA.5.  

The UK regulator on Monday said the updated Moderna vaccine was shown to provide a “strong immune response” against BA.1 as well as BA.4 and BA.5.  

“Safety monitoring showed that the  side effects observed were the same as those seen for the original Moderna booster dose and were typically mild and self-resolving, and no serious safety concerns were identified,” it added.  

Experts stress that it is still important for people to get booster shots of the original vaccine now if they have not already, given that it still provides important protection against severe disease and hospitalization. The updated vaccine targeting the newest variants, however, is expected to provide even better protection and adapt to the virus’s evolution.