Using HIV Diagnostic Data to Estimate HIV Incidence: Method and Simulation

We propose a new approach to estimate the number of new infections with the human immunodeficiency virus (HIV), by integrating the back-calculation method based on HIV diagnostic data with proportions of recent infections among newly diagnosed individuals. This is done by establishing an explicit link between the distribution of time-since-infection given being tested and the distribution of time-to-testing given being infected. The trend in the proportions of recent infections identifies the time-to-testing distribution, which would have not been identifiable based on HIV surveillance data alone, and makes back-calculation possible. The integration of the proportions of recent infections among newly diagnosed HIV into the model allows a probabilistic interpretation of the estimated proportions of recent infections based on the results of laboratory tests, in terms of the estimated distribution of the time-since-infection given being tested.