Effectiveness of COVID-19 vaccine boosters for reducing COVID-19 mortality among people aged 65 years or older, Australia, August 2023 - February 2024: a retrospective observational cohort study.

ABSTRACT:

Objectives

To assess the effectiveness of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monovalent XBB.1.5 variant vaccine for reducing coronavirus disease 2019 (COVID-19) mortality among people aged 65 years or older.

Study design

Retrospective observational cohort study; analysis of linked 2021 Australian census, Australian Immunisation Register, and death registrations data.

Setting

Australia, 1 August 2023 to 29 February 2024; dominant SARS-CoV-2 Omicron subvariants: XBB-related until early December 2023, then the BA.2.86-related JN.1.

Participants

People aged 65 years or older on 1 August 2023.

Main outcome measures

Relative vaccine effectiveness by time since most recent booster and booster type (XBB.1.5 variant or other), adjust

SUBMITTER: Liu B 

PROVIDER: S-EPMC12536084 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature