Moderna booster trial shows that attacking two COVID variants at once provides better defense against the rest

The data, published but not yet peer-reviewed, comes from the preliminary results of a clinical trial for a vaccine booster that targets the original virus along with the Beta variant. The booster was effective at treating more than just those strains, and may lead to more effective vaccines that work against future variants, Moderna said. 

Moderna found that this first so-called bivalent booster—the medical term for a vaccine that stimulates an immune response against two antigens—provided an effective defense against the original virus and the Beta variant as well as against the Delta and Omicron variants a month after it was administered. “Superiority continued six months after administration for Beta and Omicron variants of concern as well,” Moderna said in a statement.

Moderna added that it is also working on a bivalent vaccine that specifically targets Omicron, which it hopes will help mitigate the virus’s spread later this year. Results from that booster will be available in the coming months.

The company’s continued research into improved vaccines comes as Omicron’s more infectious BA.2 subvariant causes a small surge in COVID cases across the U.S. The increase is attributed to people losing their immunity from COVID as the protection of vaccines and previous infections wears off while fewer people take pandemic-related social precautions. 

On Monday, a federal judge in Florida overturned the Biden administration’s attempt to extend its face-mask mandate for public transit, citing a lack of justification for the extension. Major airlines including Delta, United, and Southwest swiftly made masking optional, with ride-share services Uber and Lyft following suit. 

Though the rate of the surge is already declining, the rise of the less dangerous BA.2 subvariant does not mean that the pandemic is ending. The virus can still mutate unpredictably.

“We believe that a bivalent booster vaccine, if authorized, would create a new tool as we continue to respond to emerging variants,” Moderna chief executive Stéphane Bancel said in a statement.