Publications & Reports

A log-odds system for waning and boosting of COVID-19 vaccine effectiveness.

Szanyi J, Wilson T, Scott N, Blakely T
Population Interventions Unit, Melbourne School of Population and Global Health, University of Melbourne, 207 Bouverie Street, Carlton, Victoria 3053, Australia. Electronic address: [email protected]


Immunity to SARS-CoV-2 following vaccination wanes over time in a non-linear fashion, making modelling of likely population impacts of COVID-19 policy options challenging. We observed that it was possible to mathematize non-linear waning of vaccine effectiveness (VE) on the percentage scale as linear waning on the log-odds scale, and developed a random effects logistic regression equation based on UK Health Security Agency data to model VE against Omicron following two and three doses of a COVID-19 vaccine. VE on the odds scale reduced by 47% per month for symptomatic infection after two vaccine doses, lessening to 35% per month for hospitalisation. Waning on the odds scale after triple dose vaccines was 35% per month for symptomatic disease and 19% for hospitalisation. This log-odds system for estimating waning and boosting of COVID-19 VE provides a simple solution that may be used to parametrize SARS-CoV-2 immunity over time parsimoniously in epidemiological models.

Link to publisher’s web site


  • Journal: Vaccine
  • Published: 20/05/2022
  • Volume: 40
  • Issue: 28
  • Pagination: 3821-3824