Effectiveness of mRNA vaccines and waning of protection against SARS-CoV-2 infection and severe covid-19 during predominant circulation of the delta variant in Italy: retrospective cohort study.

ABSTRACT:

Objectives

To estimate the effectiveness of mRNA vaccines against SARS-CoV-2 infection and severe covid-19 at different time after vaccination.

Design

Retrospective cohort study.

Setting

Italy, 27 December 2020 to 7 November 2021.

Participants

33 250 344 people aged ≥16 years who received a first dose of BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine and did not have a previous diagnosis of SARS-CoV-2 infection.

Main outcome measures

SARS-CoV-2 infection and severe covid-19 (admission to hospital or death). Data were divided by weekly time intervals after vaccination. Incidence rate ratios at different time intervals were estimated by multilevel negative binomial models with robust variance estimator. Sex, age group, brand of vaccine, priority

SUBMITTER: Fabiani M 

PROVIDER: S-EPMC8829820 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature