A comparison of four COVID-19 vaccinations shows that messenger RNA (mRNA) vaccines — Pfizer-BioNTech and Moderna — perform better against the World Health Organization’s variants of concern (VOCs) than viral vector vaccines — AstraZeneca and J&J/Janssen. Although they all effectively prevent severe disease by VOCs, the research, publishing May 17 in the open access journal PLOS Medicine, suggests that people receiving a viral vector vaccine are more vulnerable to infection by new variants.
