| Background: Men who have sex with men(MSM)have become a key high-risk group for HIV prevention and control in China,and new,efficient and acceptable intervention measures are urgently needed.Serosorting is a spontaneous HIV risk reduction behavior in MSM communities in western countries in recent years.It means that couples with the same HIV infection status may have condomless sex.At present,scholars in developed countries have found that serosorting plays a particular role in reducing new HIV infection and promoting HIV detection rate.As a further intervention,serosorting has its advantages and limitations.However,the application of serosorting in HIV-negative MSM and the effect of preventing HIV transmission in China are still unclear,so it is urgent to carry out relevant research on this population.Objective: To understand the implementation and associated factors of serosorting among HIV-negative MSM in China,clarify the correlation between serosorting and HIV self-testing(HIVST)and the reduction of HIV incidence between non-concordant anal intercourse(NCCAI)among MSM with unknown HIV infection status and serosorting.To investigate the effect of HIV self-test reagent distribution intervention on condom use,serosorting,and NCCAI in HIV negative MSM.Methods: Between 2011-2019,a cross-sectional survey and prospective cohort study was conducted among adult MSM in Shenyang,China.MSM was recruited to participate in our study through the mixed method.The cross-sectional study’s inclusion criteria were born as a male,over 18 years old,HIV negative or unknown HIV infection status,had sex with male in the past six months,willingness to receive counseling before and after testing,and willingness to provide sexual experience of the past three months.The inclusion criteria for cohort studies also included negative HIV antibody testing.A face-to-face interview survey was conducted by trained staff.The questionnaire mainly includes social demographic information,sexual behavior(serosorting,condom use,and et al.),HIV testing information,and HIV infection status of sexual partners;after the questionnaire investigation,each subject was collected 10 ml of venous blood for HIV-1antibody screening,24 mini-pool nucleic acid amplification testing(NAAT)and Treponema pallidum testing.A logistic regression model was used in the cross-sectional study to analyze the correlation factors of serosorting(We controlled for age,education level,and registered residence in the multivariable model).Generalized Estimating Equation(GEE)and COX proportional hazards regression model were used to evaluate the risk factors of HIV seroconversion in the cohort study.From August 2018 to December 2018,MSM was recruited through the We Chat Subscription and participated in the Stepped-Wedge Randomized Controlled Trial(RCT)study.The inclusion criteria were over 18 years,HIV-negative MSM which had anal sex or oral sex with men in the past six months.The eligible subjects were randomly divided into four groups(A,B,C,and D).Stepped-Wedge RCT was used to conduct a one-year prospective online survey.At 0,3,6,and 9 months after enrollment,the MSM subjects in groups A,B,C,and D were mailed HIVST reagents.The 12-month study carried out an online questionnaire survey through the Golden Data platform,a baseline questionnaire survey was carried out after enrollment,and the collected information mainly included social background information,sexual behavior,HIV testing information,etc.;follow up questionnaire survey was carried out 3-12 months after enrollment to evaluate the effect of HIVST releasing on HIV testing-related information and sexual behavior characteristics of the respondents in the past three months.The results showed that the use of HIVST reagent,the use of condom and serosorting,the awareness of HIV infection status of sexual partners and so on.Generalized estimation equation was used to evaluate the effect of HIVST on condom use,serological pairing,HIV testing level,and high-risk sexual behavior(adjusted variables of multivariate model were age and education level).Results: In the 1st part,a cross-sectional survey found the prevalence and related factors of serosorting among MSM.Five hundred fifteen eligible MSM participated in the cross-sectional study.(1)Social background information: the median age of the participants was 31 years old(IQR 25-37 years old),51.3%(264 / 515)of them had a university degree or above,and 59.6%(307 / 515)of them were single.(2)During the most recent anal intercourse: 43.1%(222 / 515)of the participants had condom anal sex,30.1%(155 / 515)had non-concordant condomless anal intercourse(NCCAI),and 21.4%(110 / 515)had serosorting behavior.The independent factors associated with serosorting behavior included higher education(college or above VS.junior high school or below)(AOR = 1.9,95% CI: 1.1-3.4),had less than two sexual partners in the past three months(AOR = 1.7,95% CI: 1.1-2.7),had sex with regular sexual partner(AOR = 2.5,95% CI:1.6-3.9),had sex with casual sexual partner(AOR = 0.4,95% CI: 0.3-0.7),tested HIV(AOR = 1.7,95% CI: 1.1-2.7)and HIV self-test(AOR = 2.9,95% CI: 1.7-4.9)in the past year,and searching for sexual partner through We Chat(VS.traditional places).(3)laboratory test results: the prevalence of HIV was 11.7%(95% CI: 9.0-14.7),the HIV prevalence of the serosorting group was 7.3%,which was not significantly different from that of the condom use group(6.3%),which was significantly lower than that of the NCCAI group(23.9%)(NCCAI VS.serosorting,AOR = 6.7,95% CI: 2.8-16.1).In the second part,a prospective cohort study found that serosorting behavior can reduce the incidence of HIV among MSM compared to NCCAI.From 2011 to 2019,1757 MSM were included in the prospective cohort study,of which 71.8%(1262 / 1757)were aged25 to 40 years old;47.3%(831 / 1757)were college or above,and 14.3%(252 / 1757)were students.The proportion of serosorting behavior increased year by year,from 13.7%in 2012 to 27.1% in 2019.The half-year,one-year,and two-year follow-up rate were86.3%,73.9%,and 58.9%,respectively.During the cohort’s follow-up period,210 people had HIV seroconversion,with a cumulative follow-up of 4708.57 person-years(PY)and a cumulative HIV incidence density of 4.5/100 PY.The annual HIV incidence from 2011 to 2019 was 6.05/100 PY,5.43/100 PY,5.30/100 PY,5.28/100 PY,5.56/100 PY,5.51/100PY,4.09/100 PY,4.82/100 PY,and 4.26/100 PY,respectively.There was no significant difference in the decreasing trend of HIV incidence(P=0.514).The HIV incidence was3.4/100 PY,4.4/100 PY,8.5/100 PY in the condom use group,serosorting behavior,and the NCCAI group.Cox proportional hazards model and GEE model analysis showed no significant difference in seroconversion between the serosorting group and condom users(P=0.103;P=0.490),which was significantly lower than that in the NCCAI group(=0.003;P=0.015).The third part,as a result,the Stepped-Wedge RCT study,found that HIVST distribution promoted MSM condom use,serosorting behavior,and HIV testing.From August 2018 to December 2018,a total of 560 eligible subjects were included in the RCT study,including 140 subjects in each group A,B,C,and D.The mean age of the subjects was26.1 ± 5.6 years old;83.2%(466 / 560)had a college degree or above;465(83.0%)of the subjects participated in at least one prospective follow-up,and 394(70.4%)completed the follow-up for 12 months.74.4%(346 / 465)of the respondents applied for self-test reagent during the study period,and we sent 1556 copies of the HIVST reagent.After HIVST intervention,the serosorting behavior in the intervention stage was significantly higher than that in the control stage(55.0% VS.45.2%,P=0.001),the condom continuous use behavior was significantly higher than that in the control stage(68.6% VS.62.9%,P=0.012),and the NCCAI behavior was significantly lower than that in the control stage(16.7% VS.21.7%,P =0.013).During the control period,the HIV testing rate of the four study groups was 37.1%(243/655)in the past three months.After the intervention of HIVST,the HIV testing rate increased significantly(84.5%).The HIV testing rate in groups A,B,C,and D increased to 91.6%,75.9%,77.2%,and 90.1%,respectively.The amount of HIV testing in the intervention group in the past three months was(m ± SD)1.53 ± 1.67 times,and that in the control group was 0.48 ± 0.72 times.The HIV testing rate in the intervention group was 1.05 times more than that in the control group(t = 20.547,P < 0.001).Gee model analysis showed that HIVST intervention significantly increased the HIV testing rate of the subjects,compared with the control stage(84.5% VS.37.1%;P <0.001),and the utilization rate of HIVST was significantly increased(81.4% VS.22.9%;P < 0.001),and the number of sexual partners(26.1% VS.34.4%;P = 0.001)and the proportion of group sex were also significantly decreased(7.7% VS.11.0;P=0.025).Compared with the control group,the MSM in the intervention group had a better knowledge of sexual partner infection.Among regular sexual partners,5%(341/650)in the control stage and 55.2%(573/1039)in the intervention stage,and among casual partners 10.5%(68/650)in the control stage and 12.6%(131/1039)in the intervention stage.Conclusion: 1.Serosorting is common among MSM in China.Serosorting,HIV detection rate,and HIVST level of MSM are increasing year by year.Serosorting is positively correlated with HIV testing and other factors.HIV testing frequency of MSM is low.Due to the lack of HIV testing,some MSM who have been infected with HIV may also think they are HIV negative,so the level of HIV testing needs to be improved urgently to avoid their wrong serosorting behavior.2.Compared with NCCAI,serosorting behavior can reduce HIV incidence,but it has no difference with condom users.It is suggested that serosorting behavior is one of the alternative HIV prevention intervention strategies for specific MSM populations.It is not recommended to switch from habitual condom use to serosorting behavior to prevent HIV infection.3.The distribution of HIV self-test reagents can effectively promote the condom use and serosorting behavior of MSM,reduce the occurrence of multiple sexual partners,group sex,and NCCAI behavior,and effectively promote the HIV testing level and the knowledge of HIV infection status of sexual partners.To provide reference information for China to further improve the policy related to HIV self-test,promote the application of self-test reagents in MSM so as to effectively control the spread of the HIV epidemic among MSM groups in China. |
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