Population Size Estimate of Men Who Have Sex With Men, Female Sex Workers, and People Who Inject Drugs in Mozambique: A Multiple Methods Approach

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 surveys, with population size estimation activities, were conducted in Mozambique in 2010 to 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 population sizes to estimate the number of people living with HIV and those unaware of their status. Results Our results suggest that Maputo has 5182 MSM, which constitutes 1.0% of the adult male population (plausibility bounds, 0.5%-2.6%); Beira, 1796 (1.4%, 1.0%-2.2%); and Nampula, 874 (0.6%, 0.4%-1.6%). The number of FSW population is 1514 (0.6%; plausibility bounds, 0.4%-1.6% of adult female city population) in Maputo, 2616 (2.2%, 1.3%-6.0%) in Beira, and 2052 (1.4%, 0.8%-5.9%) in Nampula. The number of people who inject drugs is 2518 (0.4%; plausibility bounds, 0.3%-0.5% of adult male city population) in Maputo and 1982 (1.2%, 0.6%-1.9%) in Nampula. People living with HIV ranged from 25 to 497 MSM, 382 to 664 FSW, and 712 to 1340 PWID, whereas people living with HIV unaware of their HIV positive serostatus ranged from 24 to 486 MSM, 327 to 552 FSW, and 265 to 468 PWID. Conclusions 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.