Modelling the epidemiological impact of maternal respiratory syncytial virus (RSV) vaccination in Australia

Vaccine. 2024 Dec 2;42(26):126418. doi: 10.1016/j.vaccine.2024.126418. Epub 2024 Oct 17.

Abstract

Background: Respiratory syncytial virus (RSV) is a leading cause of respiratory illness among infants. A maternal RSV vaccine that protects young infants has recently been approved for registration in Australia. We estimated the population benefits of a future year-round maternal RSV vaccination program in terms of prevented RSV infections and hospitalisations in Australia.

Methods: We described RSV transmission using an age-structured compartmental model calibrated to Australian aggregated monthly RSV-coded hospitalisations in children aged <5 years. We accounted for mother and infant interactions in the model to capture herd effects more realistically. Using the model, we estimated the annual age-specific RSV infections and hospitalisations prevented for a range of assumptions for vaccine efficacy, coverage, and durability to estimate the future impact of year-round maternal RSV vaccination on infants and the wider population.

Results: Assuming base case vaccine efficacy, 6 months duration of protection and 70% coverage, RSV hospitalisations were predicted to fall by 60% (from 3.0 to 1.2 per 100 persons) in infants aged <3 months and 40% (from 1.9 to 1.1 per 100 persons) in 3-5-month-olds. These benefits were primarily due to direct protection to infants of vaccinated mothers. This vaccine program was predicted to reduce the population-level RSV infection by about 4%. Coverage and duration assumptions were influential, with higher coverage leading to larger declines in infants <6 months, and increased duration of protection leading to additional declines in infection and hospitalisation risk in older infants aged 6-8 months.

Conclusions: With vaccine uptake similar to that achieved for other maternal vaccines in Australia, a year-round RSV maternal vaccination program is predicted to approximately halve the number of RSV hospitalisations in infants younger than 6 months. There was a small herd effect predicted in the base case but potential for larger benefits if vaccine coverage or the duration of protection exceeds base case assumptions.

Keywords: Maternal vaccination; Mathematical modelling; RSV; Respiratory syncytial virus; Transmission.

MeSH terms

  • Adult
  • Australia / epidemiology
  • Child, Preschool
  • Female
  • Hospitalization* / statistics & numerical data
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Pregnancy
  • Respiratory Syncytial Virus Infections* / epidemiology
  • Respiratory Syncytial Virus Infections* / prevention & control
  • Respiratory Syncytial Virus Vaccines* / administration & dosage
  • Respiratory Syncytial Virus Vaccines* / immunology
  • Respiratory Syncytial Virus, Human / immunology
  • Vaccination* / statistics & numerical data
  • Vaccine Efficacy

Substances

  • Respiratory Syncytial Virus Vaccines