Alliance for Pandemic Preparedness

May 25, 2021

Effectiveness of COVID-19 Vaccines against the B.1.617.2 Variant

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  • [Pre-print, not peer-reviewed] Effectiveness of the Pfizer-BioNTech vaccine against symptomatic SARS-CoV-2 infection following 1 dose was 34% against the B.1.617.2 variant of concern (first described in India) compared to 51% against the B.1.1.7 variant in a case control analysis of 12,675 sequenced cases in England (92% B.1.1.7). Two-dose effectiveness was modestly lower, with 88% against the B.1.617.2 variant compared to 93% against the B.1.1.7 variant. Single-dose effectiveness of the Oxford-AstraZeneca vaccine was similar to that of the Pfizer-BioNTech vaccine, but 2-dose effectiveness was 60% against the B.1.617.2 variant compared to 66% against the B.1.1.7 variant. Vaccine breakthrough infections were 40% more likely to be caused by the B.1.617.2 variant in sequenced cases with 1 dose of any vaccine and 60% more likely in sequenced cases with 2 doses of any vaccine compared to sequenced cases in unvaccinated individuals.

Bernal et al. (May 24, 2021). Effectiveness of COVID-19 Vaccines against the B.1.617.2 Variant. Pre-print downloaded May 25 from https://doi.org/10.1101/2021.05.22.21257658