[Incidence rates of HIV-1 epidemics among 4 high risk groups in Sichuan province during 2011-2015]

Objective: Data from the HIV/AIDS surveillance sentinel sites was used to identify the recent HIV-1 infections and to estimate the HIV-1 incidence and epidemic trends among intravenous drug users (IDU), MSM, female sex workers and men attending the sexually transmitted disease clinics in Sichuan province. Methods: Specimens collected from IDUs, MSM, female sex workers and men attending the sexually transmitted disease clinics sentinel sites were confirmed as HIV-1 positive and tested with BED-CEIA. Annual HIV-1 prevalence and incidence rates were calculated and the incidence was adjusted by McNermar method. Results: A total number of 194 223 serum specimens were collected and HIV antibody tested, with 5 297 HIV-1 positive. 4 640 of the positives underwent BED-CEIA, with 749 identified as recent infections. During 2011-2015, HIV-1 incidence rates of the four types of population appeared as 5.16% (95%CI: 4.65-5.66), 0.22% (95%CI:0.16-0.28), 0.57%(95%CI: 0.45-0.69), 7.53% (95%CI: 6.06-9.01) and 0.44% (95%CI: 0.36-0.53) respectively. Significant differences were seen in the HIV-1 incidence rates. Conclusions: The HIV-1 incidence rates of IDUs from other sentinel sites in Sichuan province, female sex workers and men attending the sexually transmitted disease clinics appeared low, showing that the AIDS prevention and control activities worked effectively. However, the HIV-1 incidence of MSM was still at high level and even rising, suggesting that HIV-1 transmission between MSM and IDUs was possible.