Summary
Certain virtues of the messenger RNA (mRNA) vaccines made by the Pfizer-BioNTech collaboration and Moderna—like others authorized for emergency use in the coronavirus pandemic—are well known and documented: They prevent symptomatic disease, curb hospitalization, and reduce death. But for public health purposes, a vaccine’s mastery at something less obvious is equally important: the ability to prevent even asymptomatic infection. By that measure, according to a brace of new studies, the mRNA vaccines stand out. “All COVID-19 vaccines are not created equal,” says Eric Topol, a physician-scientist at the Scripps Research Translational Institute. “It’s clear that the two mRNA vaccines are highly effective at preventing infection—and that others wouldn’t be expected to break the chain as well.”