COVID-19 mRNA vaccine effectiveness (second and first booster dose) against hospitalisation and death during Omicron BA.5 circulation: cohort study based on electronic health records, Portugal, May to July 2022

Euro Surveill. 2022 Sep;27(37):2200697. doi: 10.2807/1560-7917.ES.2022.27.37.2200697.

Abstract

We measured vaccine effectiveness (VE) against COVID-19-related severe outcomes in elderly people in Portugal between May and July 2022. In ≥ 80 year-olds, the second booster dose VE was 81% (95% CI: 75-85) and 82% (95% CI: 77-85), respectively, against COVID-19-related hospitalisation and death. The first booster dose VE was 63% (95% CI: 55-70) in ≥ 80 year-olds and 74% (95% CI: 66-80) in 60-79 year-olds against hospitalisation, and 63% (95% CI: 57-69) and 65% (95% CI: 54-74) against death.

Keywords: COVID-19-related death; COVID-19-related hospitalization; Omicron BA.5; SARS-CoV-2; Vaccine Effectiveness.

MeSH terms

  • Aged
  • COVID-19 Vaccines*
  • COVID-19* / prevention & control
  • Cohort Studies
  • Electronic Health Records
  • Hospitalization
  • Humans
  • Portugal / epidemiology
  • Vaccines, Synthetic
  • mRNA Vaccines

Substances

  • COVID-19 Vaccines
  • Vaccines, Synthetic
  • mRNA Vaccines