Ferris, Laura J.Kang, JemimaRathbone, Joanne A.Cruwys, TeganStevens, MarkDonaldson, Jessica L.Ranse, JamieBarlow, Fiona Kate2025-07-082025-07-081477-8939PubMed:40233836WOS:001481958300001ORCID:/0000-0001-5296-3480/work/186206632https://hdl.handle.net/1885/733766178Background: Youth mass gathering events attract thousands of travellers and produce high-exposure conditions for respiratory pathogens and other communicable diseases. Adolescents and young adults have high social circulation and show higher infection rates for viral threats like SARS-CoV2 than other age groups. How young people self-manage their elevated communicable disease risk in high-exposure travel settings such as mass events is under-researched. This study examined vaccination rates, attitudes, and adherence to non-pharmaceutical interventions (e.g., mask-wearing, physical distancing) at a youth mass event during the global COVID-19 pandemic (Oct–Dec 2021). Methods: Longitudinal cohort design with online surveys 1 month pre- (T0), during (T1-T3) and 1 month post- (T4) event. Participants were N = 291 Australian school-leavers (16–19 years) during end-of-school mass celebrations called ‘Schoolies’. Participants reported travel origin and whether they attended an official Schoolies festival (primary site), or elsewhere (secondary sites). Surveys measured COVID-19 vaccine uptake, vaccine-related attitudes, and adherence to non-pharmaceutical interventions. Results: At T0, 88% were vaccinated. Pro-vaccine attitudes were a strong positive correlate of vaccination. Primary site (versus secondary site) attendees held more favourable attitudes toward COVID-19 vaccination, perceiving higher vaccine safety, effectiveness, and importance, and lower risk. Vaccine uptake at T0 was associated with poorer subsequent physical distancing. Adherence to non-pharmaceutical interventions declined during the event; but ‘rebounded’ post-event corresponding with Australia's first omicron wave. Conclusions: Findings provide the first longitudinal picture of non-mandated COVID-19 vaccination rates and adherence to non-pharmaceutical interventions at a youth mass event, with insights for prospective management of health risks after travel vaccinations.This research was funded with support from a University of Queensland Knowledge Exchange & Translation Grant (LJF); ANU Futures Scheme Grant (TC and MS) and NHMRC Emerging Leadership Fellowship (APP1173270, TC). We thank Matthew Hornsey for his feedback and guidance on earlier drafts. The authors also thank the Gold Coast Hospital and Health Service, Queensland Health, and Department of Environment and Science, Queensland Government, for their support.7en© 2025 The AuthorsCovid-19Crowd psychologyImmunisationNpiVaccineYoung people202510.1016/j.tmaid.2025.102853105003134484