Abstract
B.1.351 is the SARS-CoV-2 variant most resistant to antibody neutralization. We demonstrate how the dose and number of immunizations influence protection. Nonhuman primates (NHP) received two doses of 30 or 100 μg of Moderna’s mRNA-1273 vaccine, a single immunization of 30 μg, or no vaccine. Two doses of 100 μg of mRNA-1273 induced reciprocal ID50 mean neutralizing antibody titers against live SARS-CoV-2 D614G and B.1.351 of 3,300 and 240, respectively. Higher neutralizing responses against B.1.617.2 were also observed after two doses compared to a single dose. Following challenge with B.1.351, there was ~4–5−log10 reduction of viral subgenomic RNA (sgRNA) and low to undetectable replication in bronchoalveolar lavages in the two-dose vaccine groups, with a 1−log10 reduction in nasal swabs (NS) in the 100 μg dose group. These data establish that a two-dose regimen of mRNA-1273 will be critical for providing upper and lower airway protection against major variants of concern.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
