Vaccine uptake and adherence to non-pharmaceutical interventions at a youth mass gathering event: A longitudinal field cohort study

Background: 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.