Population size estimates of high-risk populations, Nairobi, Kenya for 2010/11. (A) MSM population size estimates, median and plausibility bounds, Nairobi, 2010. (B) FSW population size estimates, median and plausibility bounds, Nairobi, 2010. (C) IDU population size estimates, median and plausibility bounds, Nairobi, 2011. Access the article online to view this figure in colour.