Effectiveness of mRNA COVID-19 vaccines against Omicron and Delta variants in a matched test-negative case-control study among US veterans.

ABSTRACT:

Objective

To estimate the effectiveness of messenger RNA (mRNA) booster doses during the period of Delta and Omicron variant dominance.

Design

We conducted a matched test-negative case-control study to estimate the vaccine effectiveness (VE) of three and two doses of mRNA vaccines against infection (regardless of symptoms) and against COVID-19-related hospitalisation and death.

Setting

Veterans Health Administration.

Participants

We used electronic health record data from 114 640 veterans who had a SARS-CoV-2 test during November 2021-January 2022. Patients were largely 65 years or older (52%), male (88%) and non-Hispanic white (59%).

Main outcome measures

First positive result for a SARS-CoV-2 PCR or antigen test.

Results

Against infection, boost

SUBMITTER: Young-Xu Y 

PROVIDER: S-EPMC9352567 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature