New clinical data from Moderna, Inc. this week showed that a month after using a bivalent COVID-19 booster candidate, mRNA-1273.211, superior vaccination efficacy was maintained against all variants of concern, including Beta, Delta, and Omicron.
These results stemmed from 50 µg booster doses, which demonstrated tolerability comparable to the standard mRNA-1273 booster among participants. It was a good sign for Moderna’s first bivalent booster, especially as the superiority held for Beta and Omicron variants out to six months after administration.
“We believe that these results validate our bivalent strategy, which we announced and began pursuing in February 2021,” Stéphane Bancel, CEO of Moderna, said. “The results indicate that mRNA-1273.211 at the 50 µg dose level induced higher antibody responses than the 50 µg mRNA-1273 booster, even when additional variants of concern were not included in the booster vaccine. Our latest bivalent booster candidate, mRNA-1273.214, which combines the currently authorized Moderna COVID-19 booster with our Omicron-specific booster candidate, remains our lead candidate for the fall 2022 Northern Hemisphere booster. We look forward to sharing initial data on mRNA-1273.214 later in the second quarter. We believe that a bivalent booster vaccine, if authorized, would create a new tool as we continue to respond to emerging variants.”
Updated booster candidates continue to meet the evolution of the SARS-CoV-2 virus, with both monovalent and bivalent options, though Moderna has made bivalent boosters its primary focus. Multiple bivalent booster candidates have been evaluated, with various spike protein mutations, but mRNA-1273.211 and mRNA-1273.214 include four mutations and 32 mutations, respectively.
The candidate mRNA-1273.214 focuses on Omicron-specific mutations, and it is being evaluated in a Phase 2/3 clinical study. According to Moderna, the results of this study will inform which booster it selects for the Northern Hemisphere come fall.
In the mRNA-1273.211 booster, study results showed a 2.2-fold and 2.15-fold increase in neutralizing antibody titers against Omicron – compared to the traditional mRNA-1273 booster – at one month and six months post-administration, respectively. A total of 895 people participated in the trial. Of these, 300 were given the 50 µg dose and 595 a 100 µg dose. The 50 µg dose was generally well tolerated.