May 6, 2021 -- Moderna announced that initial results from a phase II study suggest a single booster dose of its messenger RNA (mRNA) vaccine candidates mRNA-1273 or mRNA-1273.351 given to previously vaccinated individuals increased neutralizing antibody titer responses against SARS-CoV-2 and two variants.
A booster dose (50 ug) of mRNA-1273.351, the company's strain-matched booster, achieved higher neutralizing antibody titers against the B.1.351 variant prevalent in South African than a booster dose of its other candidate, mRNA-1273, according to the company.
A manuscript describing the preliminary results has been submitted as a preprint to bioRxiv and will be submitted for peer-reviewed publication upon completion of the multivalent mRNA-1273.211 booster arm, Moderna reported.