Population Size Estimate of Men who have Sex with Men, Female Sex Workers and People who Inject Drugs in Mozambique-A multiple methods approach.

Sathane, Isabel; Boothe, Makini A S; Horth, Roberta; Baltazar, Cynthia Semá; Chicuecue, Noela; Seleme, Jessica; Raymond, Henry F

BACKGROUND Accurate estimates of key population size are necessary to design programs and policies to prevent and reduce new HIV infections and to monitor the dynamics of the epidemic. The first Bio-behavioral Surveillance (BBS) surveys, with population size estimation activities, were conducted in Mozambique in 2010-2014. METHODS We used multiple methods - sequential sampling, unique object, unique event and service multipliers - to estimate the numbers of men who have sex with men (MSM), female sex workers (FSW) and people who inject drugs (PWID) living in major cities in Mozambique. Results were applied to census population sizes to estimate the number of people living with HIV (PLHIV) and those unaware of their status. RESULTS Our results suggest that Maputo has 5,182 MSM, which constitutes 1.0% of the adult male population (plausibility bounds: 0.5-2.6%), Beira 1,796 (1.4%, 1.0%-2.2%), and Nampula 874 (0.6%, 0.4%-1.6%). The population of FSW numbered 1,514 (0.6%, plausibility bounds: 0.4%- 1.6% of adult female city population) in Maputo, 2,616 (2.2%, 1.3%-6.0%) in Beira, and 2,052 (1.4%, 0.8%-5.9%) in Nampula. PWID numbered 2,518 (0.4%, plausibility bounds: 0.3%-0.5% of adult male city population) in Maputo and 1,982 (1.2%, 0.6%-1.9%) in Nampula. PLHIV ranged from 25-497 MSM, 382-664 FSW and 712-1340 PWID, while PLHIV unaware of their HIV positive serostatus, ranged from 24-486 MSM, 327-552 FSW and 265-468 PWID. CONCLUSION Although estimates generally fell within the range of those from the literature, the triangulation of survey and programmatic data over time will increasingly refine population size estimates and support the optimal allocation of limited resources.