Influenza vaccination uptake among people living with HIV in Melbourne, 2015-2025: a repeated cross-sectional study.
TL;DR
Influenza vaccination uptake among PLHIV in Melbourne remains suboptimal and was disrupted by the COVID-19 pandemic, so clinic records alone underestimate true uptake.
Abstract
Background
People living with HIV (PLHIV) are at increased risk of severe influenza-related complications, and annual vaccination is recommended. Uptake remains suboptimal and Australian data are limited. We assessed influenza vaccination uptake among PLHIV at a Melbourne specialist clinic and explored reasons for non-vaccination.
Methods
We conducted a repeated cross-sectional analysis of PLHIV attending the Melbourne Sexual Health Centre (MSHC), 2015-2025. Vaccination status was based on vaccines administered at the clinic. Segmented logistic regression assessed trends before and after the COVID-19 pandemic. A random sample of 1100 unvaccinated individuals (100/year) underwent chart review to identify reasons for non-vaccination, and an adjusted estimate incorporated self-reported external vaccination.
Results
Among 18,879 PLHIV records (median age 42, IQR 34-53), 39.6% (7474/18,879) were vaccinated at MSHC. Uptake rose from 40.4% (527/1305) in 2015 to 46.7% (779/1667) in 2019, fell to 22.9% (388/1691) in 2021, and partially recovered to 40.1% (891/2221) in 2025. Pre-pandemic uptake increased 4.8% annually (95% CI: 2.3-7.4, p < 0.001). After COVID-19 onset, vaccination odds were 65.5% lower than expected (95% CI: 60.9-69.7, p < 0.001), with subsequent annual increases of 20.3% (95% CI: 16.7-24.0). Of 1100 unvaccinated individuals reviewed, 40.6% (447) had no documented reason, 31.8% (350) reported vaccination elsewhere, and 13.5% (146) declined. Adjusted uptake including external vaccination was 58.6% (11,058/18,879).
Conclusions
Influenza vaccination uptake among PLHIV in Melbourne remains suboptimal and was disrupted by the COVID-19 pandemic. External vaccination contributes substantially, so clinic records alone underestimate true uptake. Improved prompts, standardised documentation, and integration with the Australian Immunisation Register may optimise preventive care and better capture vaccination delivery.