Unprotected sex among men who have sex with men (MSM) is the main route of HIV transmission in many countries and regions that were first affected by the HIV/AIDS epidemic, such as North America, Western Europe, and Australia [
Men who were at least 18 years of age and had sexual intercourse with at least 1 male during the previous year were eligible to participate in the study, regardless of their residence, history of HIV testing, serostatus, or treatment status.
Under the guidance of the National Protocol for HIV Sentinel Surveillance, a national MSM sentinel site was established in Chongqing and began operations in 2006. The period of surveillance was from April to June every year. A number of recruitment strategies were adopted, including receiving referrals from nongovernment organizations, adopting the snowball method, and using online recruitment. The numbers of participants were 561, 602, 400, 390, and 376 in 2006, 2008, 2010, 2012, and 2013, respectively.
The survey site was located in a STI/HIV clinic of Chongqing CDC. After obtaining informed consent from study subjects, trained investigators administered a questionnaire to collect information on the study subjects’ demographic characteristics, homosexual behaviors, heterosexual behaviors, commercial sex, and access to HIV testing and intervention. Blood samples were taken from subjects for HIV and syphilis testing. HIV infection was screened with enzyme-linked immunosorbent assay (ELISA; Zhuhai Livzon Diagnostics Inc., China). Subjects with a positive result in the first test were retested with another ELISA reagent (Beijing Wantai Biological Pharmacy Enterprise Co., Ltd., China). HIV infection was diagnosed if both tests were positive. For syphilis testing, ELISA assay (Zhuhai Livzon Diagnostics Inc., China) and TRUST assay (Shanghai Rongsheng Biological Pharmacy Enterprise Co., Ltd., China) were used, and there would be a confirmed diagnosis if both ELISA and TRUST positive could be diagnosed syphilis positive. However, only ELISA assay was used in 2006 and 2008.
Data were entered into a web-based electronic database designed by the National HIV Sentinel Surveillance Working Group. Upon completion of data inputs, data were then exported to the SAS software for statistical analysis (SAS Institute Inc., USA, version 9.3). Demographic characteristics were presented and compared using chi-square test for different rounds of samples. Observed trends in HIV and syphilis prevalence, as well as a number of sexual risk behaviors, were analyzed with chi-square trend test (Cochran-Armitage method). Since the study samples across the study period were different in age proportion, trends were also examined separately for participants aged between 18 and 24 years, 25 and 34 years, and those aged over 45 years. All reported
A total of 2329 MSM were enrolled in the sentinel surveillance surveys: 561 participated in 2006, 602 in 2008, 400 in 2010, 390 in 2012, and 378 in 2013 (Table
Demographics of Participants among Men Who Have Sex with Men in Chongqing.
Demographics | 2006 | 2008 | 2010 | 2012 | 2013 | Total | ||||||
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Age (years) | ||||||||||||
18–24 | 561 | 158 (28.2) | 602 | 322 (53.5) | 400 | 184 (46.0) | 390 | 144 (36.9) | 376 | 153 (40.7) | 2329 | 961 (41.3) |
25–34 | 561 | 211 (37.6) | 602 | 205 (34.1) | 400 | 172 (43.0) | 390 | 201 (51.5) | 376 | 175 (46.5) | 2329 | 964 (41.4) |
≥35 | 561 | 192 (34.2) | 602 | 75 (12.5) | 400 | 44 (11.0) | 390 | 45 (11.5) | 376 | 48 (12.8) | 2329 | 404 (17.3) |
Marital Status | ||||||||||||
Single | 561 | 416 (74.2) | 602 | 516 (85.7) | 391 | 341 (87.2) | 390 | 335 (85.9) | 376 | 320 (85.1) | 2320 | 1928 (83.1) |
Married or divorced | 561 | 145 (25.8) | 602 | 86 (14.3) | 391 | 50 (12.8) | 390 | 55 (14.1) | 376 | 46 (14.9) | 2320 | 382 (16.5) |
Residence | ||||||||||||
Local | 561 | 441 (78.6) | 602 | 373 (62.0) | 398 | 316 (79.4) | 390 | 326 (83.6) | 376 | 319 (84.8) | 2327 | 1775 (76.3) |
Non-Local | 561 | 120 (21.4) | 602 | 229 (38.0) | 398 | 82 (20.6) | 390 | 64 (16.5) | 376 | 57 (15.2) | 2327 | 552 (23.7) |
Education (years) | ||||||||||||
0–9 | 561 | 137 (24.5) | 602 | 97 (16.2) | 399 | 14 (3.6) | 390 | 18 (4.6) | 376 | 28 (7.4) | 2328 | 294 (12.6) |
10–12 | 561 | 198 (35.3) | 602 | 174 (28.8) | 399 | 91 (22.8) | 390 | 49 (12.6) | 376 | 71 (18.9) | 2328 | 583 (25.0) |
≥13 | 561 | 226 (40.2) | 602 | 331 (55.0) | 399 | 294 (73.7) | 390 | 323 (82.8) | 376 | 277 (73.7) | 2328 | 1451 (62.3) |
HIV prevalence among the study participants showed an upward trend and increased from 13.0% to 19.7% from 2006 to 2013 (
Dynamic trends of HIV, Syphilis, and other sexually transmitted diseases among men who have sex with men in Chongqing.
Infections/Diseases | 2006 | 2008 | 2010 | 2012 | 2013 |
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HIV | 561 | 73 (13.0) | 602 | 98 (16.3) | 400 | 50 (12.5) | 390 | 76 (19.5) | 376 | 74 (19.7) | 0.004 |
Age (years) | |||||||||||
<25 | 158 | 10 (6.3) | 322 | 39 (12.1) | 184 | 22 (12.0) | 144 | 26 (18.1) | 153 | 30 (19.6) | <0.001 |
25–34 | 211 | 29 (13.7) | 205 | 29 (14.1) | 172 | 19 (11.0) | 201 | 36 (17.9) | 175 | 34 (19.4) | 0.085 |
≥35 | 192 | 34 (17.7) | 75 | 20 (26.7) | 44 | 9 (20.5) | 45 | 14 (13.1) | 48 | 10 (20.8) | 0.18 |
Syphilis | 561 | 54 (9.6) | 602 | 70 (11.6) | 400 | 25 (6.3) | 390 | 11 (2.8) | 376 | 11 (2.9) | <0.001 |
Age (years) | |||||||||||
<25 | 158 | 6 (3.8) | 322 | 29 (9.0) | 184 | 12 (6.5) | 144 | 3 (2.1) | 153 | 4 (2.6) | 0.044 |
25–34 | 211 | 19 (9.0) | 205 | 26 (12.7) | 172 | 9 (5.2) | 201 | 5 (2.5) | 175 | 3 (1.7) | <0.001 |
≥35 | 192 | 29 (15.1) | 75 | 15 (20.0) | 44 | 4 (9.1) | 45 | 3 (6.7) | 48 | 4 (8.3) | 0.056 |
HIV and syphilis coinfection | 73 | 15 (20.5) | 98 | 29 (29.6) | 50 | 7 (6.5) | 76 | 2 (2.1) | 74 | 9 (12.2) | <0.001 |
Self-report STD diagnosis in the last year | 561 | 112 (20.0) | 602 | 122 (20.3) | 400 | 22 (5.5) | 390 | 11 (2.8) | 376 | 9 (2.4) | <0.001 |
Age (years) | |||||||||||
<25 | 158 | 34 (21.5) | 322 | 58 (18.0) | 184 | 11 (6.0) | 144 | 6 (4.2) | 153 | 3 (2.0) | <0.001 |
25–34 | 211 | 53 (25.1) | 205 | 46 (22.4) | 172 | 7 (4.1) | 201 | 1 (0.5) | 175 | 4 (2.3) | <0.001 |
≥35 | 192 | 25 (13.0) | 75 | 18 (24.0) | 44 | 4 (9.1) | 45 | 4 (8.9) | 48 | 2 (4.2) | 0.072 |
HIV and Other STDs coinfection | 73 | 26 (35.6) | 98 | 24 (24.5) | 50 | 6 (12.0) | 76 | 6 (7.9) | 74 | 1 (1.4) | <0.001 |
Percentage of receiving HIV testing in the last year increased from 16.8% to 43.1% (
HIV testing behavior and condom use among men who have sex with men in Chongqing.
Health behaviors | 2006 | 2008 | 2010 | 2012 | 2013 |
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Ever received HIV testing in previous year | 561 | 94 (16.8) | 602 | 195 (32.4) | 400 | 198 (49.5) | 390 | 165 (42.3) | 376 | 162 (43.1) | <0.001 |
Age (years) | |||||||||||
<25 | 158 | 29 (18.4) | 322 | 96 (29.8) | 184 | 84 (45.7) | 144 | 58 (40.3) | 153 | 63 (41.2) | <0.001 |
25–34 | 211 | 44 (20.9) | 205 | 79 (38.5) | 172 | 91 (52.9) | 201 | 94 (46.8) | 175 | 81 (46.3) | <0.001 |
≥35 | 192 | 21 (10.9) | 75 | 20 (26.7) | 44 | 23 (52.3) | 45 | 13 (28.9) | 48 | 18 (37.5) | <0.001 |
Condom use during last sexual intercourse with man | 466 | 242 (51.9) | 500 | 330 (66.0) | 375 | 250 (66.7) | 336 | 231 (68.8) | 338 | 240 (71.0) | <0.001 |
Age (years) | |||||||||||
<25 | 135 | 80 (59.3) | 268 | 175 (65.3) | 171 | 117 (68.4) | 124 | 84 (67.7) | 137 | 98 (71.5) | <0.001 |
25–34 | 187 | 97 (51.9) | 172 | 123 (71.5) | 161 | 108 (67.1) | 173 | 119 (68.8) | 154 | 113 (73.4) | <0.001 |
≥35 | 144 | 65 (45.1) | 60 | 32 (53.3) | 43 | 25 (58.1) | 39 | 28 (71.8 ) | 47 | 29 (61.7) | 0.002 |
Consistent condom use in the last 6 months with men | 466 | 115 (24.7) | 500 | 185 (37.0) | 375 | 155 (41.3) | 336 | 150 (44.6) | 338 | 162 (47.9) | <0.001 |
Age (years) | |||||||||||
<25 | 135 | 48 (35.6) | 268 | 97 (36.2) | 171 | 75 (43.9) | 124 | 50 (40.3) | 137 | 60 (43.8) | <0.001 |
25–34 | 187 | 45 (24.1) | 172 | 71 (41.3) | 161 | 64 (39.8) | 173 | 82 (47.4) | 154 | 88 (57.1) | <0.001 |
≥35 | 144 | 22 (15.3) | 60 | 17 (28.3) | 43 | 16 (37.2) | 39 | 18 (46.2) | 47 | 14 (29.8) | <0.001 |
Sex with women | 561 | 185 (33.0) | 602 | 95 (15.8) | 400 | 45 (11.3) | 390 | 45 (11.5) | 376 | 33 (8.8) | <0.001 |
Condom use during last sexual intercourse with woman | 185 | 57 (30.8) | 95 | 43 (45.3) | 45 | 15 (33.3) | 45 | 22 (48.9) | 33 | 17 (51.5) | 0.008 |
Consistent condom use in the last 6 months with women | 185 | 40 (21.6) | 95 | 38 (40.0) | 45 | 12 (26.7) | 45 | 19 (42.2) | 33 | 15 (45.5) | 0.001 |
Commercial sex with men | 561 | 39 (6.9) | 602 | 51 (8.4) | 384 | 16 (4.0) | 376 | 14 (3.6) | 367 | 9 (2.4) | <0.001 |
HIV/AIDS awareness rate | 561 | 488 (87.0) | 602 | 522 (86.7) | 400 | 385 (96.3) | 390 | 385 (98.7) | 376 | 368 (98.0) | <0.001 |
Despite huge amounts of effort in HIV prevention and control, this analysis has shown that there has been a significant increase in HIV prevalence among MSM population in Chongqing from 2006 to 2013, coinciding with the general trend in China [
Our results suggest that there is a significant increase in condom usage and more MSM are willing to seek HIV testing. This could be partly a result of the numerous MSM intervention projects implemented by the local government, as well as the work of all the MSM nongovernment organizations in Chongqing these years [
There are a few reasons for the discrepancy between HIV prevalence increase and condom use rate. Firstly, prevalence reflects joint action of incidence and mortality. Prevalence might go up when both incidence and mortality go down. In fact, with expansion of ART, the mortality does decrease significantly in recent years in China [
The analysis indicated a significant decline in syphilis infection rate in Chongqing, which could also be seen in other Chinese cities [
There are several limitations in this analysis. Firstly, the sentinel surveillance relied on convenience-based samples and the participants were recruited through several different methods in every round. Since the characteristics of samples in each survey showed statistically different results, stratified analysis was performed to minimize the effect of the change in population structure.
Secondly, changes in HIV tests may also influence trends. HIV antibody tests have improved over the years. New generation assays are more accurate and the rate of false-positive results that may skew prevalence becomes lower. Thirdly, Reporting bias due to desirability is more likely to affect the assessment of trend data. Since incidence is the best indicator of HIV trend in a short period, trend analysis based on incidence estimates was strongly recommended for future study.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Gang Zeng and Liangui Feng contribute to the paper equally on data analysis, interpretation of the findings, and paper drafting.
The study was funded by the National Science Foundation of China (71003089, 71373008). The authors also gratefully acknowledge the staff in voluntary STD/HIV testing and counseling clinic in Chongqing CDC, whom without their contribution to the questionnaire survey and laboratory work the study would not have been completed.