Time-varying effectiveness of the mRNA-1273, BNT162b2 and Ad26.COV2.S vaccines against SARS-CoV-2 infections and COVID-19 hospitalizations and deaths: an analysis based on observational data from Puerto Rico

ABSTRACT

BackgroundAs of October 1, 2021 2,217,547 individuals were fully vaccinated against COVID-19 in Puerto Rico. Since the vaccination process commenced on December 15, 2020 111,052 laboratory-confirmed SARS-CoV-2 infections have been reported. These data permitted us to quantify the benefits of the immunization campaign and to compare effectiveness of the mRNA-1273 (Moderna), BNT162b2 (Pfizer), and Ad26.COV2.S (J&J) vaccines. MethodsDepartment of Health databases holding vaccination status, SARS-CoV-2 test results, and COVID-19 hospitalizations and deaths were integrated. We fit a statistical model that adjusted for time-varying incidence rates and age to estimate vaccine effectiveness and hospitalization and death relative risks. Code and data are provided here https//github.com/rafalab/vax-eff-pr. ResultsAt the peak of their protection, mRNA-1273, BNT162b2, and Ad26.COV2.S had an effectiveness of 90% (88%-91%), 87% (85%-89%), and 58% (51%-65%), respectively. After four months, effectiveness waned to about 70%, 60%, and 30%. We found no evidence that effectiveness was different after the Delta variant became dominant. For those infected, the vaccines provided further protection against hospitalization and deaths across all age groups. All vaccines had a lower effectiveness for those over 85 years, with a larger decrease for the Ad26.COV2.S vaccine. Overall, thousands of hospitalizations and deaths were avoided thanks to the vaccines. ConclusionsThe mRNA-1273 and BNT162b2 vaccines were highly effective across all age groups. They were still effective after four months although the protection waned. The Ad26.COV2.S vaccine was effective but to a lesser degree, especially for older age groups.