Covid-19 Booster Shows Promise Against Variants in Early Study, Moderna Says
Booster shots improved immune responses of people who had been given Moderna’s vaccine, early study finds
Booster shots under development by Moderna Inc. MRNA -6.19% helped improve immune responses against some variants among people given the company’s Covid-19 vaccine in an early study, the biotech company said Wednesday.
The results, though preliminary, are a sign that adding booster shots several months after original vaccinations could bolster people’s immunity against more contagious strains of the virus.
The company tested giving people boosts with either a single dose of its original vaccine, mRNA-1273, or a new vaccine, mRNA-1273.351, which was modified to better match a virus variant first identified in South Africa and known as B.1.351.
The subjects received the booster shots about six to eight months after they had received the second dose of the original vaccine as part of a midstage, Phase 2 study that started last year.
Both booster shots increased immune-system agents known as neutralizing antibodies against two variants of concern: B.1.351 and P.1, which was first identified in Brazil, according to Moderna.
The immune responses were measured 15 days following the booster doses, the company said.
A booster dose of the variant-targeted vaccine induced higher neutralizing antibody concentrations against the B.1.351 variant than a booster dose of Moderna’s original vaccine, Moderna said.
“We are encouraged by these new data, which reinforce our confidence that our booster strategy should be protective against these newly detected variants,” Moderna Chief Executive Stephane Bancel said.