Longitudinal trends of recent HIV-1 infections in Slovenia (1986-2012) determined using an incidence algorithm

Resolving dilemma whether the rise in the number of HIV diagnoses represents an actual increase in HIV transmissions or is a result of improved HIV surveillance is crucial before implementing national HIV prevention strategies. Annual proportions of recent infections (RI) among newly diagnosed persons infected with HIV-1 in Slovenia during 27 years (1986-2012) were determined using an algorithm consisting of routine baseline CD4 and HIV viral load measurements and the Aware BED EIA HIV-1 Incidence Test (BED test). The study included the highest coverage of persons diagnosed with HIV during the entire duration of an HIV epidemic in a given country/region (71%). Out of 416 patients, 170 (40.9%) had a baseline CD4 cell count less than 200 cells/mm(3) and/or HIV-1 viral load less than 400 copies/ml and were characterized as having a long-standing infection (LSI). The remaining 246 patients were additionally tested using the BED test. Overall, 23% (97/416) of the patients were labeled RI. The characteristics significantly associated with RI were as follows: younger age, acute retroviral syndrome, CDC class A and other than C, no AIDS defining illnesses, HIV test performed in the past, a higher viral load, and a higher CD4 cell count. An interesting trend in the proportion of RI was observed, with a peak in 2005 (47% of RI) and the lowest point in 2008 (12%) in parallel with a rise in the numbers of new HIV diagnoses. This study could help promote the idea of introducing periodic HIV incidence monitoring using a simple and affordable algorithm.