(Nature, 2021-09-07) Dagan, Noa; Barda, Noam; Biron-Shental, Tal; Makov-Assif, Maya; Key, Calanit; Kohane, Isaac; Hernán, Miguel A.; Lipsitch, Marc; Hernandez-Diaz, Sonia; Reis, Ben; Balicer, Ran D.
To evaluate the effectiveness of the BNT162b2 mRNA vaccine among pregnant women, we conducted an observational cohort study of pregnant women 16 years or older, with no history of SARS-CoV-2, who were vaccinated between December 20, 2020 and June 3, 2021. 10,861 vaccinated pregnant women were matched to 10,861 unvaccinated control women using demographic and clinical characteristics. Study outcomes included documented infection with SARS-CoV-2, symptomatic COVID-19, COVID-19-related hospitalization, severe illness and death. Estimated vaccine effectiveness from 7 through 28 days after the second dose was 97% (95% CI 91%-100%) for any documented infection, 96% (86-100%) for infections with documented symptoms, and 85% (32%-100%) for COVID-19-related hospitalization. Only one event of severe illness was observed in the unvaccinated group, and no deaths were observed in either group. In summary, the BNT162b2 mRNA vaccine was estimated to have high vaccine effectiveness among pregnant women, similar to the effectiveness estimated in the general population.
