Moderna starts trial for Omicron-specific booster shot, follows Pfizer

The coronavirus variant has quickly become dominant in many parts of the world, driving up infections and straining healthcare systems.

Moderna Inc said on Wednesday it had started a mid-stage study, testing a booster dose of its Covid-19 vaccine specifically designed to target the Omicron coronavirus variant, a day after rival Pfizer Inc launched a similar trial.

The company said while a third shot of its original coronavirus vaccine increased neutralizing antibodies against the variant at the lower dose, their levels declined six months after the booster dose was administered.

However, neutralizing antibodies remained detectable in all participants, Moderna said.

While studies have indicated that Omicron results in a less severe COVID-19 than seen during previous waves, the variant has quickly become dominant