HIV incidence in Asia: a review of available data and assessment of the epidemic.

Rates of new HIV infections in Asia are poorly characterized, likely resulting in knowledge gaps about infection trends and the most important areas to target for interventions. We conducted a systematic review of peer-reviewed English language publications and conference abstracts on HIV incidence in thirteen countries - Bangladesh, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Taiwan, Thailand, and Vietnam. We obtained data on HIV incidence rate, incidence estimation method, population, and risk factors for incident infection. Our search yielded 338 unique incidence estimates from 70 published articles and 41 conference abstracts for eight countries. A total of 138 (41%) were obtained from prospective cohort studies and 106 (31%) were from antibody-based tests for recent infection. High HIV incidence rates were observed among commercial sex workers (0.4-27.8 per 100 person-years), people who inject drugs (0.0-43.6 per 100 person-years) and men who have sex with men (0.7-15.0 per 100 person-years). Risk factors for incident HIV infection include brothel-based sex work and cervicitis among commercial sex workers; young age, frequent injection use and sharing needles or syringes among people who inject drugs; multiple male sexual partners, receptive anal intercourse and syphilis infection among men who have sex with men. In the countries with available data, incidence rates were highest in key populations and varied widely by incidence estimation method. Established surveillance systems that routinely monitor trends in HIV incidence are needed to inform prevention planning, prioritize resources, measure impact, and improve the HIV response in Asia.