Box 1 PICOS statement

Population

Children, adults and elderly of all ages and with or without chronic conditions

Intervention

Pneumococcal, influenza and/or COVID-19 vaccination (all vaccine types)

Comparison

Vaccinated versus unvaccinated (placebo) or vaccinated with other vaccine type

Outcome

Antibiotic use (all types) or antibiotic prescriptions

Study design

Randomised controlled trials, observational studies (case-cohort, control, cross-sectional), modelling studies, cost studies