COVID-19 vaccines have yielded definitive prevention and major reductions in morbidity and mortality from SARS-CoV-2 infection, even in the context of emerging and persistent variants-of-concern. Newer variants have revealed less vaccine protection against infection and attenuation of vaccine effects on transmission. COVID-19 vaccines still likely reduce transmission compared to not being vaccinated at all, even with variants of concern, however determining the magnitude of transmission reduction is constrained by challenges of performing these studies, requiring accurate linkage of infections to vaccine status and timing thereof, particularly within households. In this review we synthesize the currently available data on the impact of COVID-19 vaccines on infection, serious illness, and transmission; we also identify the challenges and opportunities associated with policy development based on this data.
COVID-19 Vaccines and SARS-CoV-2 Transmission in the Era of New Variants: A Review and Perspective