Two half or full shots of Moderna COVID vaccine yield similar antibody levels: Data Byte
Immunogenicity data from Moderna’s COVID-19 vaccine hint that prime-boost vaccination with half the authorized dose may provide the same level of protection as the full dose.
The data lend at least some weight to the idea of stretching supplies by administering two 50 μg shots instead of two 100 μg shots. The catch, however, is that correlates of protection have not yet been established for COVID-19 vaccines, which means decision-makers are still largely groping in the dark.
In Phase IIa testing, mean neutralizing antibody levels evoked by Moderna COVID-19 Vaccine (mRNA-1273) were nearly identical after two injections of either 50 or 100 µg of the mRNA vaccine. The doses also produced comparable responses in the company’s Phase I trial.
Both studies found that prior to the booster shot, mean titers in subjects who had received a single injection of the half dose were slightly lower than those in subjects given the authorized dose, and had overlapping confidence intervals.
In the Phase IIa study, the gap between the 50 μg and 100 μg doses closed after the second injection.