Alliance for Pandemic Preparedness

April 12, 2021

Evidence for Increased Breakthrough Rates of SARS-CoV-2 Variants of Concern in BNT162b2 MRNA Vaccinated Individuals

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  • [Pre-print, not peer-reviewed] A case-control study of individuals with SARS-CoV-2 infection in Israel who received the Pfizer vaccine (cases) versus unvaccinated carriers (controls) found that the predominant SARS-CoV-2 variant among vaccine recipients with a positive SARS-CoV-2 PCR result differed depending on their timing in the vaccine course. Compared to controls, vaccinated individuals infected at least a week after the second dose were disproportionally infected with the B.1.351 variant (OR=8), while those infected between two weeks after the first dose and one week after the second dose were disproportionally infected by B.1.1.7 (odds ratio of 26:10). The B.1.351 variant was not evaluated at this time point due to low case numbers of B.1.351. The authors suggest there may be reduced vaccine effectiveness against both variants of concern under different conditions of number of doses and dose timing. The B.1.1.7 variant was found to be the predominant strain over the study period.

Kustin et al. (Apr 9, 2021). Evidence for Increased Breakthrough Rates of SARS-CoV-2 Variants of Concern in BNT162b2 MRNA Vaccinated Individuals. Pre-print downloaded Apr 12 from https://doi.org/10.1101/2021.04.06.21254882