Comparative effectiveness of bivalent BA.4-5 and BA.1 mRNA booster vaccines among adults aged ≥50 years in Nordic countries: nationwide cohort study.

ABSTRACT:

Objective

To estimate the effectiveness of the bivalent mRNA booster vaccines containing the original SARS-CoV-2 and omicron BA.4-5 or BA.1 subvariants as the fourth dose against severe covid-19.

Design

Nationwide cohort analyses, using target trial emulation.

Setting

Denmark, Finland, Norway, and Sweden, from 1 July 2022 to 10 April 2023.

Participants

People aged ≥50 years who had received at least three doses of covid-19 vaccine (that is, a primary course and a first booster).

Main outcome measures

The Kaplan-Meier estimator was used to compare the risk of hospital admission and death related to covid-19 in people who received a bivalent Comirnaty (Pfizer-BioNTech) or Spikevax (Moderna) BA.4-5 or BA.1 mRNA booster vaccine as a fourth dose (second boost

SUBMITTER: Andersson NW 

PROVIDER: S-EPMC10364194 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature