Asymptomatic and pre-symptomatic cases of COVID-19 contribution to spreading the epidemic and need for targeted control strategies / 中华流行病学杂志

The asymptomatic carrier state of COVID-19 has become a topic of concern for preventing a possible epidemic rebound. This review describes and defines the COVID-19 asymptomatic carrier state and outlines methods for identifying counting and reporting these cases. The author elaborates that the asymptomatic carrier state can be further divided into asymptomatic infection and pre-symptomatic infection after extended follow-up based on the nature of disease progression. The author presents the limited available data about infectiousness of asymptomatic and pre-symptomatic cases and their possible contributions to the overall epidemic of COVID-19 observed so far in China. Challenges of a possible second epidemic wave of COVID-19 caused by asymptomatic and pre-symptomatic cases are discussed and suggestions for control strategies and scientific research are provided.

Follow-up of community injecting drug user cohort, 2014-2017 / 中华流行病学杂志

Objective@#To explore the methods of establishing and maintaining community injecting drug user (IDU) cohort.@*Methods@#From June 2014 to June 2017, a community survey was conducted on basis of local needle and syringe exchange site to recruit 200 HIV sero-negative IDU for a prospective cohort study in Longyang district of Baoshan city, Yunan province. Follow-up was carried out every six month to investigate high risk drug use behavior and sexual behavior, and blood samples were collected from them for the tests of HIV and HCV serum antibodies. The cohort would be opened every 12 months to replenish the cohort to 200 subjects.@*Results@#The follow up was conducted for 3 years in 229 IDUs. Cohort follow-up rate was 93.0% (213/229) for 6 months, 92.1% (211/229) for 12 months, 91.7% (200/218) for 18 months, 87.2% (190/218) for 24 months, 86.0% (172/200) for 30 months and 86.0% (172/200) for 36 months.@*Conclusion@#The community IDU cohort has a high follow-up rate.

Initial follow-up and CD4+ T cell count test of newly reported students HIV cases in China, 2013-2017 / 中华预防医学杂志

Objective@#To analyze first follow-up and CD4+ T (CD4) cell count test of newly reported students HIV cases in China from 2013 to 2017.@*Methods@#Data were collected from both Case Reporting Cards and Follow-up Cards from China Information System for HIV/AIDS Control and Prevention between 1st January 2013 and 31st December 2017. The inclusion criteria are 15-24 years old students who were newly diagnosed with HIV infection. Logistic regression model was used to analyze relevant factors of the first CD4 test results less than 200 CD4 cells/μl.@*Results@#There were 12 037 newly diagnosed students HIV cases from 2013 to 2017. Most cases were male (97.7%), 19-22 years old (65.1%) and Han ethnicity (90.5%). At the time of diagnosis, the route of HIV infection was most frequently homosexual contact (82.2%). The majority of cases (46.9%) were diagnosed at HIV voluntary counseling and testing (VCT) location. About 2 465 (20.6%) students had unprotected intercourse in the past 3 months, of which 1 387 (56.8%) had 1 sexual partner, 610 (25.0%) with 2 sexual partners, 273 (11.2%) with 3 partners and 170 (7.0%) with more than 4 partners. 11.0% and 28.9% of cases had initial CD4 counts less than 200 cells/μl and 200-349 cells/μl. Compared to the male, younger than 18 years old and diagnosed at VCT location, female (OR=2.09, 95%CI: 1.51-2.89), aged 21 to 22 years (OR=1.25, 95%CI: 1.06-1.47), diagnosed in hospital settings (OR=2.20, 95%CI: 1.89-2.57) and preoperative testing (OR=1.36, 95%CI: 1.07-1.73) had greater proportion of the first CD4 test result less than 200 CD4 cells/μl.@*Conclusion@#The number of newly diagnosed students HIV cases significantly increased in past 5 years, and the proportion of late diagnosis was high. Female, aged 21 to 22 years, diagnosed in hospital settings and preoperative testing were related to the first CD4 test result less than 200 CD4 cells/μl.

HIV and syphilis infection and related medical treatment status of low-fee female sex workers in three provinces of China, 2012-2015 / 中华预防医学杂志

Objective@#To understand the HIV and syphilis infection and related treatment status of low-fee female sex workers (FSWs) in 3 provinces of China.@*Methods@#Four cross-sectional survey data of low-fee FSWs from six cities (counties) in Guangxi, Yunnan and Hunan Province between October 2012 and July 2015 were obtained from the national science and technology major special project intervention study for reducing sexually transmitted diseases (STDs) and acquired immunodeficiency syndrome (AIDS) in low-fee FSWs' database, which included social demographic characteristics, sexual service characteristics and related medical care seeking behaviors, etc. A total of 2 050 subjects were included in the database.@*Results@#The age of the subjects was (35.16±9.76) years old, with a minimum age of 15 and a maximum age of 67. Those who use condoms every time in commercial sex accounted for 58.9% (n=1 206). Among the reasons of not using condom, the proportion of client reluctant to use was the highest (81.0% (n=682)). Only 38.1% (n=782) was tested for HIV in the last six months. HIV confirmed positive rate was 6.8% (n=139), previous positive accounts for 76.3% (n=106). Rate of antiviral therapy was 55.4% (n=77). By the end of 2015, the loss rate of antivirus treatment was 18.2% (n=14). Those who self-reported symptoms of sexually transmitted diseases in the last 6 months accounted for 9.4% (n=191). 50.3% (n=96) of reporters chose to go to formal hospitals, 23.0% (n=44) chose to go to private clinics and 20.4% (n=39) chose their own medication. The syphilis infection rate was 13.5% (n=277), among them, 91.3% (n=253) were asymptomatic.@*Conclusion@#Among low-fee FSWs, the rates of HIV and syphilis infection are higher, the condom consistent use rate, HIV antibodies and syphilis test rate are lower. In this group, active seeking medical idea is poor, the rate of anti-virus treatment and the rate of seeking medical treatment in formal medical institutions is low.

Qualitative study on unprotected sexual behaviors among male students who have sex with men in Beijing / 中华预防医学杂志

Objective@#To investigate the related factors of unprotected sexual behaviors among male students who have sex with men in Beijing.@*Methods@#Male students who have sex with men were recruited from May 2018 to July 2018 at two voluntary counseling and testing (VCT) clinics in Beijing by convenient sampling method. Information being collected during in-depth personal interviews with a semi-structured outline included ways to seek sexual partners, sexual partners characteristics, attitude of condom use, incidence and causes of unprotected sexual behaviors, rush poppers and alcohol use. The text information was summarized and analyzed by Nvivo 11.0 software.@*Results@#A total of 35 male students who have sex with men were recruited and interviewed, the median of age was 22 years old (P25-P75: 21-24 years old). We found that incomprehensive knowledge of condom use, low risk perception of non-anal sexual behaviors, rush poppers and alcohol use were risk factors of unprotected sexual behaviors on individual level. Besides, sex with regular sex partners, partners who were much older or not from campus, and insertive partners are more likely to be unprotected. Furthermore, refusal of condom use by sexual partners and low self-efficacy of decision-making on condom use were the main reasons for unprotected sexual behaviors among male student who have sex with men.@*Conclusion@#Lack of condom use knowledge, low risk perception of non-anal sexual behaviors and insufficient ability to refuse non-condom requirements for regular sex partners, partners who were much older or not from campus, and insertive partners are related factors of unprotected sexual behaviors among male students who have sex with men.

Risk of HIV infection and its factors among men who have sex with men: a geosocial networking application-based survey in Beijing of China, 2017 / 中华预防医学杂志

Objective@#To assess risk of HIV infection and its risk factors among men who have sex with men (MSM) in Beijing, China.@*Methods@#We conducted a cross-sectional online survey in October, 2017. Inclusion criteria of participants were: aged 18 year or more; resided in Beijing; conducted homosexual activities in past six months; self-reported HIV status as negative or unclear. Demographic information, HIV test history, social media use, and high-risk sexual behaviors were collected by a self-reporting questionnaire, and a HIV risk assessment tool was used to assess HIV risk of MSM, 5 388 particpants were finally enrolled in the study. Logistic regression model was used to analyze factors associated with risk of HIV infection.@*Results@#Of the total 5 388 participants, most were 18-29 years old (64.35%), and the proportion of medium and high HIV risk score was 40.36%. The odds of medium and high HIV risk score among MSM who logged onto the app 1-20 times per week and>20 times per week were higher comparing with those who logged onto the app<1 time per week (OR=1.22, 95%CI: 1.02-1.46; OR=1.69, 95%CI: 1.38-2.06, respectively); MSM who completed college or higher education had lower probability of medium and high HIV infection risk, comparing with those who only had high school education level (OR=1.25, 95%CI:1.09-1.43) or junior or below education level (OR: 1.27, 95%CI: 1.05-1.53); MSM who did not conduct HIV test in past year had lower risk of medium and high HIV infection risk comparing with MSM who conducted HIV test in past year (OR=0.87, 95%CI: 0.77-0.99), and those who reported their HIV infection status unclear had higher probability of medium and high HIV infection risk than MSM who reported their HIV infection status negative (OR: 1.63, 95%CI: 1.44-1.86).@*Conclusion@#The proportion of MSM who were in medium and high HIV infection risk score was high in Beijing. Lower level of education, high frequency of social media use, conducted HIV test in past year, and unclear of their own HIV infection status were associated with medium and high level of HIV infection risk.

Estimation of HIV diagnosis rate with CD4+ T-lymphocyte level and infected-time model in Dehong Prefecture, Yunnan Province / 中华预防医学杂志

Objective@#To estimate the total number of people infected with HIV and to calculate the diagnosis rate of HIV in Dehong Prefecture, Yunnan Province.@*Methods@#Through the comprehensive AIDS prevention and treatment information system, we collected and analyzed the relevant information of the new diagnosis report of HIV in Dehong Prefecture, Yunnan Province in 2006-2015, mainly including age, sex, infected transmission, CD4+ T-lymphocyte counts, diagnostic time and so on. The content of the study was to establish a model method for estimating the diagnosis rate of HIV in Dehong. First, used the first CD4+ T-lymphocyte count after HIV diagnosis to estimate the date of infection. Then based on the estimated time from HIV infection to diagnosis we can estimate the diagnosis delay distribution which in turn can be used to account for individuals infected but not yet diagnosed and thus estimated the total number of HIV infections (diagnosed and undiagnosed). Finally, the number of new infections in each year was added to estimate the total number of infected people, and the number of people who had been diagnosed was divided by the total number of infected persons to obtain the proportion of HIV diagnosis rate.@*Results@#There were 8 215 reported cases in Dehong from 2006 to 2015, of which 1 297 cases were reported in 2007 (15. 8%) and 361 cases (4.4%) in 2015. The diagnosis rate of newly infected persons were 88% in 2005 and before. And from 2006 to 2015, the diagnosis rate of newly infected persons were 75%, 71%, 68%, 66%, 61%, 58%, 53%, 45%, 40% and 33%, respectively. The total number of newly infected persons in 2005 and before was 11 197 cases. The annual new infected number from 2006 to 2015 was 653, 671, 723, 640, 509, 468, 369, 375, 285 and 224 cases. The total number of people infected with HIV in Dehong was 16 114 cases, and the diagnosis rate was 87.7%.@*Conclusion@#The diagnosis rate of HIV in Dehong was at a high level. Since 2008, the annual number of new infections in Dehong has been declining.

Acceptability of HIV testing using oral quick self-testing kit in men who have sex with men / 中华流行病学杂志

Objective To evaluate the acceptability of oral quick HIV self-testing in men who have sex with men (MSM).Methods From April 2013 to April 2014,MSM in Beijing and Nanning of China were recruited for an observational study including baseline survey and follow-up,including questionnaire survey,oral HIV self-testing and clinic-based HIV confirmation testing.The sensitivity and specificity of oral quick self-testing were evaluated through comparing the results of oral quick testing with blood testing.The acceptability and associated factors were evaluated by logistic model.Results A total of 510 MSM were recruited at baseline survey and 279 accepted follow-up.The sensitivity of the oral self-test was 86.00％ (43/50) and specificity was 98.23％ (445/453) at baseline survey.At baseline survey,78.63％ (401/510) of the MSM showed willingness to use oral quick HIV self-testing.The associated factors included unprotected anal intercourse with a regular male partner in the past 6 months (aOR=0.30,95％ CI:0.10-1.00) and preference of oral quick HIV self-testing (aOR=7.32,95％CI:1.61-33.31).At baseline survey,34.51％ (176/510) of the MSM reported that oral quick HIV self-testing was the preferred testing method rather than blood testing,which was associated with their birth places-urban area.Conclusion The acceptability of oral quick HIV self-testing in MSM in the two cities was high.

Application of Bernoulli Process Model fitting the effect of intervention measures on sexual transmission among HIV sero-discordant couples / 中华流行病学杂志

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 sero-discordant 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.

Changes of proportion regarding consistent condom use and syphilis infection among low-fee female sex workers aged 35 and above / 中华流行病学杂志

Objective To investigate the changes of proportion on both consistent condom use and syphilis infection among low-fee female sex workers aged 35 and above (LFSW),in order to provide evidence for targeted intervention strategies.Methods A total of six cities-Liuzhou city and Pingnan couty of Guigang city of Guangxi Zhuang Autonomous Region,Jinghong city of Xishuangbanna Dai autonomous prefecture and Dali city of Dali Bai autonomous prefecture of Yunnan province,Zhangjiajie city and Jianghua Yao autonomous county of Yongzhou city Hunan province were involved in this study,with 60 eligible participants needed in each city,estimated through a pre-study.The first cross-sectional survey was completed from October 2012 to January 2013.Face-to-face questionnaire interview was carried out to collect information on socio-demography,work-related information and condom use situation.Blood was collected for syphilis testing.The second cross-sectional survey was carried out from June to September,2015 under the same procedure.Results A total of 371 and 403 eligible participants were included in the first and second survey,respectively.When comparing the two surveys,we noticed that the average age showed a slight change,from 42.4 years to 43.8 years old (t=3.537,P＜0.001) and the average price for every commercial sex exchange increased from 36.8 RMB to 49.5 RMB (t=11.961,P＜0.001).In the first survey,46.9％ (174/371) of the participants had more than two years of experience working as LFSW,compared to 61.3％ (247/403) in the second survcy (x2=16.125,P＜0.001).Also,46.9％ (174/371) of the participants consistently used condoms with clients in the past month in the first survey versus 64.3％ (259/403) (x2=23.641,P＜0.001) in the second one.Rates of syphilis infection were found from 15.9％ (59/371) in the first survey reduced to 7.2％ (29/403) in the second survey (x2=14.533,P＜0.001).Conclusion Compared with the first survey,the proportion of consistent condoms use showed an increase.Although the proportion of syphilis infection decreased in the second survey,the scope did not meet the criteria on syphilis,set by the government.Targeted intervention strategies on condom promotion and syphilis control should be implemented consistently in this population.

Characteristics of HIV sexually transmission and challenges for controlling the epidemic in China / 中华流行病学杂志

Sexual transmission became the major mode of HIV infection in this country and accounted for 95％ of the newly diagnosed cases,67％ and 28％ of heterosexual and male homosexual infections,respectively,in 2016.Heterosexual transmission was mostly reported in South-west while male homosexual transmission in North-east and major metropolitan areas.Elderly and young students became the two special groups of people with increased reported HIV cases in the past years,with major modes of transmission as both heterosexual and homosexual.HIV testing and treatment of all HIV infections have been national control strategies and implemented and have significantly reduced HIV sexual transmission among sero-discordant couples.However,about one-third HIV infections remained undiagnosed.HIV infection through sexual transmission will remain a challenge in the years to come.

Acceptability of HIV testing using oral quick self-testing kit in men who have sex with men / 中华流行病学杂志

Objective To evaluate the acceptability of oral quick HIV self-testing in men who have sex with men (MSM).Methods From April 2013 to April 2014,MSM in Beijing and Nanning of China were recruited for an observational study including baseline survey and follow-up,including questionnaire survey,oral HIV self-testing and clinic-based HIV confirmation testing.The sensitivity and specificity of oral quick self-testing were evaluated through comparing the results of oral quick testing with blood testing.The acceptability and associated factors were evaluated by logistic model.Results A total of 510 MSM were recruited at baseline survey and 279 accepted follow-up.The sensitivity of the oral self-test was 86.00％ (43/50) and specificity was 98.23％ (445/453) at baseline survey.At baseline survey,78.63％ (401/510) of the MSM showed willingness to use oral quick HIV self-testing.The associated factors included unprotected anal intercourse with a regular male partner in the past 6 months (aOR=0.30,95％ CI:0.10-1.00) and preference of oral quick HIV self-testing (aOR=7.32,95％CI:1.61-33.31).At baseline survey,34.51％ (176/510) of the MSM reported that oral quick HIV self-testing was the preferred testing method rather than blood testing,which was associated with their birth places-urban area.Conclusion The acceptability of oral quick HIV self-testing in MSM in the two cities was high.

Application of Bernoulli Process Model fitting the effect of intervention measures on sexual transmission among HIV sero-discordant couples / 中华流行病学杂志

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 sero-discordant 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.

Changes of proportion regarding consistent condom use and syphilis infection among low-fee female sex workers aged 35 and above / 中华流行病学杂志

Objective To investigate the changes of proportion on both consistent condom use and syphilis infection among low-fee female sex workers aged 35 and above (LFSW),in order to provide evidence for targeted intervention strategies.Methods A total of six cities-Liuzhou city and Pingnan couty of Guigang city of Guangxi Zhuang Autonomous Region,Jinghong city of Xishuangbanna Dai autonomous prefecture and Dali city of Dali Bai autonomous prefecture of Yunnan province,Zhangjiajie city and Jianghua Yao autonomous county of Yongzhou city Hunan province were involved in this study,with 60 eligible participants needed in each city,estimated through a pre-study.The first cross-sectional survey was completed from October 2012 to January 2013.Face-to-face questionnaire interview was carried out to collect information on socio-demography,work-related information and condom use situation.Blood was collected for syphilis testing.The second cross-sectional survey was carried out from June to September,2015 under the same procedure.Results A total of 371 and 403 eligible participants were included in the first and second survey,respectively.When comparing the two surveys,we noticed that the average age showed a slight change,from 42.4 years to 43.8 years old (t=3.537,P＜0.001) and the average price for every commercial sex exchange increased from 36.8 RMB to 49.5 RMB (t=11.961,P＜0.001).In the first survey,46.9％ (174/371) of the participants had more than two years of experience working as LFSW,compared to 61.3％ (247/403) in the second survcy (x2=16.125,P＜0.001).Also,46.9％ (174/371) of the participants consistently used condoms with clients in the past month in the first survey versus 64.3％ (259/403) (x2=23.641,P＜0.001) in the second one.Rates of syphilis infection were found from 15.9％ (59/371) in the first survey reduced to 7.2％ (29/403) in the second survey (x2=14.533,P＜0.001).Conclusion Compared with the first survey,the proportion of consistent condoms use showed an increase.Although the proportion of syphilis infection decreased in the second survey,the scope did not meet the criteria on syphilis,set by the government.Targeted intervention strategies on condom promotion and syphilis control should be implemented consistently in this population.

Characteristics of HIV sexually transmission and challenges for controlling the epidemic in China / 中华流行病学杂志

Sexual transmission became the major mode of HIV infection in this country and accounted for 95％ of the newly diagnosed cases,67％ and 28％ of heterosexual and male homosexual infections,respectively,in 2016.Heterosexual transmission was mostly reported in South-west while male homosexual transmission in North-east and major metropolitan areas.Elderly and young students became the two special groups of people with increased reported HIV cases in the past years,with major modes of transmission as both heterosexual and homosexual.HIV testing and treatment of all HIV infections have been national control strategies and implemented and have significantly reduced HIV sexual transmission among sero-discordant couples.However,about one-third HIV infections remained undiagnosed.HIV infection through sexual transmission will remain a challenge in the years to come.

Antiretroviral treatment discontinuation and its influencing factors among HIV-infected patients who initiated ART from 2012 to 2015 in Wenshan prefecture, Yunnan Province / 中华预防医学杂志

Objective@#To understand the antiretroviral treatment (ART) discontinuation rate and its influencing factors among HIV infected patients who initiated ART between 2012 and 2015 in Wenshan prefecture, Yunnan province.@*Methods@#Demographic characteristics, baseline informations of ART, initial treatment regimens and follow-up status of a total of 4 354 patients who initiated ART from 2012 to 2015 in Wenshan prefecture were collected. A historical cohort study was used to describe the discontinuation incidence rate of ART. Life table was used to estimate cumulative retention rate and Cox proportional hazard model was used to determine the influencing factors of ART discontinuation.@*Results@#The percentage and incidence rate of discontinuation were 25.1% (1 092/4 354) and 14.53 per 100 person-years among patients who initiated ART from 2012 to 2015 in Wenshan prefecture. ART retention rates were 88%, 83%, 78%, 74% at 6th month, 12th month, 18th month, 24th month, respectively. The multivariate Cox proportional hazard regression model showed that male patients were at a higher risk of discontinuation (HR=1.24, 95%CI: 1.09-1.41) than female patients, patients aged ≥50 years were at a higher risk of discontinuation (HR=1.27, 95%CI: 1.06-1.53) than patients aged<30 years, discontinuation hazard among patients who were unmarried or divorced or widowed was 1.30 times (HR:1.30, 95%CI: 1.14-1.48) as patients who were married or cohabitation, discontinuation hazard among patients infected with HIV through injection drug use (IDU) was 1.49 times (HR:1.49, 95%CI: 1.23-1.82) as those infected through heterosexual transmission, patients with a baseline CD4 cell count<350/μl (HR=1.34, 95%CI: 1.13-1.58) or ≥500/μl (HR=1.36, 95%CI: 1.09-1.71) were at a higher risk of discontinuation than those with a baseline CD4 cell count from 350/μl to 500/μl, patients initiating ART in 2014 (HR=1.25, 95%CI: 1.04-1.50) or in 2015 (HR=1.26, 95%CI: 1.02-1.55) were at a higher risk of discontinuation than those initiating ART in 2012.@*Conclusion@#There is an uptrend for ART discontinuation rate in Wenshan prefecture. Male, 50 years or older, unmarried or divorced or widowed, transmission route as IDU, baseline CD4 count <350/μl or ≥500/μl are risk factors of ART discontinuation.

The situation and associated factors of facility-based HIV testing among men who sex with men in Beijing / 中华预防医学杂志

Objective@#To understand the prevalence of facility-based HIV testing and its associated factors among men who have sex with men (MSM) in Beijing city.@*Methods@#An application-based cross-sectional survey was employed to understand HIV site test situation and associated factors. The survey was carried out from May 14th to 21st, 2016. Users of a smart phone application for gay dating were recruited and those eligible for this survey were investigated with an online self-administered questionnaire. Information of demographics, sexual behaviors, facility-based HIV testing history and recreational drug abuses were collected. The multivariate logistic regression was used to make comparison among different groups and assess associated factors.@*Results@#A total of 7 494 participants were enrolled in the survey with mean age of (28.81 ± 7.38) years, 87.14% (6 530/7 494) sought sexual partners through internet. The proportion of facility-based HIV testing in 1 year was 42.55% (3 189/7 494), MSM who were 25-29 years had higher proportion of facility-based HIV testing in 1 year, the proportion was 45.56%(1 104/2 423). Among MSM who could insist in using condom during anal sex (50.46% (1 539/3 050)), the proportion of HIV site testing in 1 year was higher. The MSM who reported seeking healthcare for symptoms of a sexually transmitted infections (STIs) in the past year or ever using recreational drug had higher proportion of facility-based HIV testing, the proportions were 56.81% (409/720) and 52.00% (1 340/4 917), respectively. Compared with alone cohabitation, cohabitating was associated with decreased odds of HIV facility-based testing in past 1 year(odds ratio (OR)= 0.79, P<0.001). Compared with homosexual sexual orientation, bisexual sexual orientation was associated with decreased odds of facility-based HIV testing (OR=0.83, P=0.004). With the increasing of number of male anal sex partners, the odds of HIV facility-based testing was increasing (OR=1.31, P<0.001) But with the decreasing of the frequency of condom using with male anal sex partners, the odds of facility-based HIV testing was decreasing (OR=0.85, P=0.014). Using recreational drugs (OR=1.36, P<0.001) and seeking healthcare for symptoms of a STI in the past 1 year (OR=1.73, P<0.001) were associated with decreased odds of HIV site testing.@*Conclusion@#MSM in Beijing had lower proportion of facility-based HIV testing in past 1 year. Multiple anal sex partners, using recreational drugs, seeking healthcare for symptoms of a STI in the past year, cohabitating, bisexual sexual orientation, and lower frequency of condom using with male anal sex partners were associated with the odds of HIV facility-based testing in past 1 year.

Effect of laboratory referencing on data analysis of community viral load in HIV positive MSM from 15 cities, China / 中华流行病学杂志

Objective To compare the community viral load (CVL) among MSM in 15 cities in China using standardized national reference sources.Methods The study analyzed the existing database of National Major Science and Technology Project of China.The database was established with serial random survey of MSM HIV CVL among MSM in 15 cities from 2013 to 2015.VL tests were conducted in 15 laboratories with different equipment and methods,including RT-PCR,nucleic acid sequence based amplification (NASBA),branched DNA testing (bDNA) and Abbott M2000 RealTime system (M2000).Based on proficiency test for 15 laboratories conducted by National HIV Reference Laboratory,VL test values detected with EasyQ,bDNA and M2000 were converted and standardized into resultant values of TaqMan 2.0.Software SPSS 17.0 was used to produce descriptive statistics for the dataset.Results From 2014 to 2015,the 15 testing sites were found to use a number of different viral load detection techniques.In 2014,the community viral load values were (2.38 ±1.47) and (2.99 ± 1.31) in 15 testing sites,while in 2015 these values were found to be (2.07± 1.34) and (2.72± 1.19).The measurement of community VL was done using standard benchmarks of ≤200 copies/ml,≤400 copies/ml and ≤1 000 copies/ml,that were used for reference for now.Conclusion It is necessary to use standard detection method to improve the comparability of annual results.Using a standardized rate of ≤400 copies/ml or ≤ 1 000 copies/ml for successful control of VL was found with high stability for the result comparison among different areas.

Comparison of different methods in dealing with HIV viral load data with diversified missing value mechanism on HIV positive MSM / 中华流行病学杂志

Objective To compare results of different methods in organizing HIV viral load (VL) data with missing values mechanism. Methods We used software SPSS 17.0 to simulate complete and missing data with different missing value mechanism from HIV viral loading data collected from MSM in 16 cities in China in 2013. Maximum Likelihood Methods Using the Expectation and Maximization Algorithm (EM), regressive method, mean imputation, delete method, and Markov Chain Monte Carlo (MCMC) were used to supplement missing data respectively. The results of different methods were compared according to distribution characteristics, accuracy and precision. Results HIV VL data could not be transferred into a normal distribution. All the methods showed good results in iterating data which is Missing Completely at Random Mechanism (MCAR). For the other types of missing data, regressive and MCMC methods were used to keep the main characteristic of the original data. The means of iterating database with different methods were all close to the original one. The EM, regressive method, mean imputation, and delete method under-estimate VL while MCMC overestimates it. Conclusion MCMC can be used as the main imputation method for HIV virus loading missing data. The iterated data can be used as a reference for mean HIV VL estimation among the investigated population.

Data distribution and transformation in population based sampling survey of viral load in HIV positive men who have sex with men in China / 中华流行病学杂志

Objective To understand the distribution of population viral load (PVL) data in HIV infected men who have sex with men (MSM), fit distribution function and explore the appropriate estimating parameter of PVL. Methods The detection limit of viral load (VL) was ≤ 50 copies/ml. Box-Cox transformation and normal distribution tests were used to describe the general distribution characteristics of the original and transformed data of PVL, then the stable distribution function was fitted with test of goodness of fit. Results The original PVL data fitted a skewed distribution with the variation coefficient of 622.24%, and had a multimodal distribution after Box-Cox transformation with optimal parameter (λ) of-0.11. The distribution of PVL data over the detection limit was skewed and heavy tailed when transformed by Box-Cox with optimal λ=0. By fitting the distribution function of the transformed data over the detection limit, it matched the stable distribution (SD) function (α=1.70, β=-1.00, γ=0.78, δ=4.03). Conclusions The original PVL data had some censored data below the detection limit, and the data over the detection limit had abnormal distribution with large degree of variation. When proportion of the censored data was large, it was inappropriate to use half-value of detection limit to replace the censored ones. The log-transformed data over the detection limit fitted the SD. The median (M) and inter-quartile ranger (IQR) of log-transformed data can be used to describe the centralized tendency and dispersion tendency of the data over the detection limit.