Initial report of decreased SARS-CoV-2 viral load after inoculation with the BNT162b2 vaccine.

Levine-Tiefenbrun, Matan; Yelin, Idan; Katz, Rachel; Herzel, Esma; Golan, Ziv; Schreiber, Licita; Wolf, Tamar; Nadler, Varda et al. · Nat Med · 2021

retrospective_cohort · Level III

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Abstract

Beyond their substantial protection of individual vaccinees, coronavirus disease 2019 (COVID-19) vaccines might reduce viral load in breakthrough infection and thereby further suppress onward transmission. In this analysis of a real-world dataset of positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test results after inoculation with the BNT162b2 messenger RNA vaccine, we found that the viral load was substantially reduced for infections occurring 12-37 d after the first dose of vaccine. These reduced viral loads hint at a potentially lower infectiousness, further contributing to vaccine effect on virus spread.

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