Effect of Covid-19 Vaccination on Transmission of Alpha and Delta Variants

In this study, 37% of 146,000 PCR-tested contacts of infected persons in England were positive for SARS-CoV-2. Transmission of the alpha variant from twice-vaccinated index patients was rarer than that from unvaccinated index patients (adjusted rate ratio with BNT162b2, 0.32). Vaccine protection waned over time and was more effective against the alpha strain than against the delta strain.

https://www.nejm.org/do/10.1056/NEJMdo006428/full/?fbclid=IwAR3eT_EqmAsj6LITUF2YOplMbJi2bQs3get-veX9gygY5oNX8UAzArw8dE8

Créditos: Comité científico Covid