Estimation of the number of people living with HIV in Arak, Iran: application of network scale-up method for hidden populations

Introduction: Human immunodeficiency virus (HIV) remains a significant public health challenge worldwide.In this study, we aimed to estimate the number of people living with HIV (PLHIV) in Arak, Iran, using network scale-up method (NSU). Material and methods:This cross-sectional study was conducted among residential population in Arak located in the center of Iran.In total, 1,604 individuals participated.Sampling locations were selected by creating a list of crowded and busy centers in the city, which were considered as clusters.Two locations were then randomly selected within each cluster.The main variable was the number of PLHIV/AIDS known by each participant among their active social network in Arak during the past five years.To estimate the number of PLHIV, NSU method was used.Results: Among the participants, 51.1% (n = 819) were females, of which 29.2% (n = 468) were identified as housewives.The mean age of participants was 39.2 years (SD: 14.1).Using the NSU method, the population size estimation of PLHIV in Arak was determined as 1,075, equivalent to a prevalence rate of 178.2 per 100,000 population (95% CI: 145.4-214.3%per 100,000 population).The size estimation of PLHIV was determined as 248 (prevalence rate: 83.1; 95% CI: 73.1-94.0%per 100,000 population) and 827 (prevalence rate: 271.5; 95% CI: 253.5-290.4% per 100,000 population) for females and males, respectively. Conclusions:The estimated prevalence of HIV was higher than the number of detected cases in Arak.Key high-risk populations for HIV should receive more support for HIV testing and confidentiality implementation.