Population Size Estimation of Groups at High Risk of HIV/AIDS in Men, Using Network Scale Up in South of Iran, 2017

Background: Size estimation of hidden populations are complicate with direct methods. This study aimed to size estimate groups at high risk of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) in men, using Network Scale Up in South of Iran. Methods: 500 men between 18 and 45 years old were recruited. 8 populations at high risk of HIV were defined: opium users, unknown drug users, ecstasy users, alcohol users, injection drug users (IDUs), men who have extramarital sex with females (MSF), men who have sex with female sex workers (MFSW), and men who have sex with other men (MSMs). We asked respondents whether they know anybody in their social networks of the above subpopulation (probability method), If yes, how many people do they know (frequency method). Findings: Estimates derived in the frequency method were higher than the probability method. Based on the frequency method, 4.38% [95% confidence interval (CI): 2.58%-6.17%] of men used alcohol at least once in last year. 2.16% (95% CI: 0.88%-3.43%) had extramarital sex, 1.94% (95% CI: 0.73%-3.14%) were opium users, 1.88% (95% CI: 0.68%-3.07%) had experience of unknown drug consumption, 1.64% (95% CI: 0.52%-2.75%) had sex with a female sex worker, 0.48% (95% CI: 0.12%-1.08%) were ecstasy drugs user, 0.34% (95% CI: 0.17%-0.85%) had sex with other men, and 0.26% (95%CI:0.18%-0.70%) were injection drug users. Conclusion: The size of the population of alcohol users and men who have extramarital sex is higher than other high-risk groups. Developing a special preventive program is needed to control HIV transmission based on the frequency of high-risk groups in each region.