Moderna Says Its COVID-19 Booster Shots Show Promise Against Variants

Moderna said booster shots under development have helped improve immune responses against some COVID-19 variants among people administered its vaccine in a preliminary study, reports the Wall Street Journal . The drugmaker tested giving people boosts with either a single dose of its original vaccine, mRNA-1273, or the new mRNA-1273.351 vaccine, which was tweaked to better match a virus variant first identified in South Africa. The booster shots were administered roughly six to eight months after subjects received the second dose of the original vaccine as part of a midstage, Phase 2 study that started in 2020. Moderna said both booster shots increased immune-system agents known as neutralizing antibodies against the B.1.351 and P.1 variants, which was first identified in Brazil. The experimental boosters were generally well tolerated, with most side effects like fatigue and headache on the mild or moderate side. "We are encouraged by these new data, which reinforce our confidence that our booster strategy should be protective against these newly detected variants," said Moderna Chief Executive Stephane Bancel.