Impact of booster vaccination on the control of COVID-19 Delta wave in the context of waning immunity: application to France in the winter 2021/22

Euro Surveill. 2022 Jan;27(1):2101125. doi: 10.2807/1560-7917.ES.2022.27.1.2101125.


Europe has experienced a large COVID-19 wave caused by the Delta variant in winter 2021/22. Using mathematical models applied to Metropolitan France, we find that boosters administered to ≥ 65, ≥ 50 or ≥ 18 year-olds may reduce the hospitalisation peak by 25%, 36% and 43% respectively, with a delay of 5 months between second and third dose. A 10% reduction in transmission rates might further reduce it by 41%, indicating that even small increases in protective behaviours may be critical to mitigate the wave.

Keywords: France; SARS-CoV-2; modelling; vaccination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 Vaccines / administration & dosage*
  • COVID-19* / prevention & control
  • France / epidemiology
  • Humans
  • Immunization, Secondary*
  • SARS-CoV-2
  • Seasons
  • Vaccination


  • COVID-19 Vaccines

Supplementary concepts

  • SARS-CoV-2 variants