VACCINE-PREVENTABLE HOSPITALISATION IN MENTAL HEALTH SERVICE USERS: A BOOSTER IS NEEDED

ABSTRACT

Background: COVID-19 has highlighted the essential role of vaccination in preventing illness, modifying illness severity and averting hospital care. Mental health (MH) service users have low vaccination rates for many conditions, but evidence on individual and health system impacts is limited. Methods: The NSW Mental Health Living Longer links population-wide data from NSW hospitals and community MH services. We calculated hospitalisation rates and incidence rate ratios for vaccine-preventable conditions including hepatitis, influenza and pneumococcal pneumonia, comparing MH service users to other NSW residents. Rates were standardised for age and socio-economic disadvantage. Results: Over 12 months there were 14,530 vaccine preventable admissions in NSW, occupying 94,241 bed days. MH service users had a more than fourfold increased risk of admission for vaccine-preventable conditions (adjusted incidence rate ratio = 4.7;95% confidence interval = [4.5, 5.0]), with the highest relative risk in people aged 40-65 years. One-quarter of total excess potentially preventable bed days in MH service users were due to vaccine-preventable conditions, including respiratory illness. MH service users comprised 2.3% of the NSW population but contributed nearly 15% of vaccine-preventable bed days. Additional analyses will be presented examining specific conditions, demographic and clinical subgroups. Conclusion: Low vaccination rates have serious impacts for MH service users. Strategies to overcome barriers and support vaccination uptake could have quick and substantial benefits for individuals and health systems. Supporting uptake of COVID-19 vaccination will be essential to avoid further amplifying health inequalities for people using MH services.