COVID-19 vaccine effectiveness against severe disease from SARS-CoV-2 Omicron BA.1 and BA.2 subvariants – surveillance results from southern Sweden, December 2021 to March 2022
Open Access
- 5 May 2022
- journal article
- research article
- Published by European Centre for Disease Control and Prevention (ECDC) in Eurosurveillance
- Vol. 27 (18), 2200322-13
- https://doi.org/10.2807/1560-7917.es.2022.27.18.2200322
Abstract
We compared vaccine effectiveness against severe COVID-19 between December 2021 and March 2022 when Omicron BA.1 and BA.2 were the dominating SARS-CoV-2 variants in Scania county, Sweden. Effectiveness remained above 80% after the transition from BA.1 to BA.2 among people with at least three vaccine doses but the point estimate decreased markedly to 54% among those with only two doses. Protection from prior infection was also lower after the transition to BA.2. Booster vaccination seems necessary to maintain sufficient protection.Keywords
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