Abstract

Objectives: Understanding and monitoring the HIV epidemic is essential for developing and evaluating public health responses. The Joint United Nations Programme on AIDS (UNAIDS) Estimation and Projection Package (EPP) and Spectrum have become a standard tool to interpret HIV surveillance systems in many settings, particularly in low- and middle-income countries where surveillance data is often based on serial cross-sectional prevalence studies and not on notifications. EPP has not previously been used to evaluate the HIV epidemic in Australia. We derived best HIV estimates using EPP and assumptions that reflect the current understanding of HIV epidemiology in Australia and compared derived estimates with independent estimates and estimates from mathematical models using backprojections method.

Methods: The epidemic curves for different population groups (i.e., men who have sex with men, injecting drug users, and low-risk population) generated by EPP were combined with antiretroviral therapy (ART) data into a demographic projection model, Spectrum to determine the consequences of the HIV epidemic in Australia.

Results: The overall pattern of the HIV epidemic was consistent with both independent estimates and backprojection modelling estimates. However, the number of HIV-infected females, AIDS-related deaths, and the number in need of ART estimated by EPP were approximately 3.7 times, 20 times, and 6.3 times, respectively higher than independent estimates based on our current surveillance system. EPP estimates of new HIV infections were, however, half the number of independent and back-projection estimates.

Conclusions: These findings suggest that customized tools that are tailored to the unique epidemiology and surveillance mechanisms in each setting are required to enable effective programmatic response and policy.

Keywords: Antiretroviral therapy; HIV/AIDS; Modelling; Surveillance; Transmission risk