Estimation of the number of female sex workers in Yangon and Mandalay, Myanmar.

While it is known that HIV prevalence is higher among key affected populations, such as female sex workers (FSW), the sizes of these populations are difficult to estimate. This study aimed to estimate the numbers of FSW in the two largest cities of Myanmar using multiple data-driven methods. A total of 778 FSW (450 in Yangon, 328 in Mandalay) were recruited though time-location sampling during November and December 2013. Five multiplier methods and a modified wisdom of the crowds method were applied within the surveys to calculate the number of FSW in each city. The median of the methods estimated a population size of FSW in Yangon at 4992 (acceptable upper and lower bounds: 4482-5753) and 3315 (2992-3368) in Mandalay. These estimates translate to a population prevalence of FSW among adult women (age 18-49 years) of 0.35 % (0.32-0.40 %) in Yangon and 0.77 % (0.69-0.84 %) in Mandalay.