[Application of Bernoulli Process Model fitting the effect of intervention measures on sexual transmission among HIV sero-discordant couples]

Objectives: To undersand the outcomes of major intervention measures on sexual transmission among HIV sero-discordant couples. Methods: Bernoulli Process Model was applied to model the major influencing factors of HIV transmission among HIV sero-discordant couples. The major influencing factors appeared as consistent condom use, antiretroviral therapy, frequency of sexual behavior. These parameters were from the HIV sero-discordant couples in 30 counties in 4 provinces (Guangxi Zhuang Autonomous Region, Yunnan Province, Xinjiang Uygur Autonomous Region and Henan provinces) from January 1, 2011 to December 31, 2012. According to the main factors, modeling-intervention strategies and measures on reduction HIV transmission among serodiscordant couples were formed. Results: Data from the present proportion of consistent condom use (85%) modeling and the coverage of antiretroviral treatment (60%) showed that, the proportion of cumulative seroconversion among the spouses was 1.76%. Results from the sensitivity analysis on modeling the consistent condom use and the antiretroviral treatment showed that, when the coverage of antiretroviral treatment was as 90% and the proportion of consistent condom use increased from 50% to 90%, with 80.7% of the risk of spouse seroconversion could be reduced. Or, when the proportion of consistent condom use was as 90% and the coverage of antiretroviral treatment increased from 50% to 90%, with 64.5% of the risk of spouse seroconversion could be reduced. Conclusions: With measures as consistent condom use plus provision of timely antiretroviral therapy to HIV positive index spouses, the risk of sexual transmission among sero-discordant couples could be greatly reduced.