HIV elimination and population viral load.

www.thelancet.com/hiv Vol 3 November 2016 e507 WHO and UNAIDS have recommended treatment as pre vention for the global elimination of HIV. Treatment suppresses an individuals’ viral load, making them less infectious. The higher the coverage of treatment, the lower the viral load in the population, and the lower the incidence of new infections. Incidence is very diffi cult to measure directly as it requires frequent testing of the entire population. Therefore population viral load, which can be used as an indirect measure of the eff ectiveness of treatment as pre vention, has been proposed as a proxy for incidence. Popu lation viral load is the average (mean or median) viral load, calculated from the distribution of viral loads in diagnosed and undiagnosed individuals. To date, only one HIV epidemic has been shown to be close to elimination: the Danish HIV epidemic in men who have sex with men (MSM). HIV incidence in Danish MSM began to decrease soon after the introduction of eff ective therapies in 1996; by 2013, incidence was close to the WHO elimination threshold of one new HIV infection per 1000 individuals per year. Here we show how the population viral load changed, from 1996 onwards, as coverage increased and incidence decreased. We calculated the population viral load each year between 1996 and 2013. To make these calculations we determined the number of diagnosed and undiagnosed MSM who were living with HIV, and their viral loads. We used data from the Danish HIV Cohort Study (DHCS), an ongoing population-based study, to make these determinations for diagnosed individuals. Diagnosed individuals were either not yet on treatment, on treatment but not virally suppressed, or on treatment and virally suppressed (<200 copies per mL). For the population viral load calculation we used individuals’ the evidence base for providing PrEP to sub-Saharan African migrants and other migrant and ethnic minority communities would further reinforce existing health disparities. Given the recent EMA approval, this call to rethink the European PrEP research agenda could not be more timely.