The national prevalence rate was estimated to be 0.37 %. The southern region accounted for almost 50 % of total cases, and had the highest number of cases compared to the other three regions of Vietnam: northern, central and highland. Vietnam is still facing an HIV epidemic that has occurred primarily in PWIDs and female sex workers . Recently, the epidemic has been rising significantly among MSM . The team visited these hotspots to estimate the numbers of MSM in each. With the assistance of MSM and hotspot owners, additional hotspots were identified, yielding a total of 745. Local health staff, with the help of MSM peers, accessed these venues and conducted rapid interviews of hotspot owners and several MSM to get information for estimating the size of the MSM population and how to approach MSM in each hotspot. MSM were invited to participate in this survey if they were at least 16 years old and self reported having had oral and/or anal sex with another male in the past 12 months. Those with any history of poor blood clotting were excluded due to the risk of prolonged bleeding after drawing of blood, and those with hearing disorders were excluded due to the difficulty for them to clearly hear and understand the questions being asked and responding to them correctly.There were differences between provinces in sample sizes because of variations in prevalence estimates and/or limited funding. The HIV prevalence among MSM per site was estimated using proxy data of nearby provinces . We also had personal communications with peer educators and staff of provincial AIDS centers from the study provinces to gain insights into the probable HIV prevalence and risk behaviors among MSM to estimate the HIV prevalence for selecting suitable sample sizes. The prevalence of HIV in MSM in southern Vietnam was estimated to be approximately 4 %,horticulture solutions and the desired precision was set at 2 %, indicating that a sample size of 369 was needed; allowing 10 % for incomplete data and specimen damage, the sample size was rounded to 400.
However, since funding was insufficient, the sample size was lower for four provinces, where the estimated prevalence was approximately 3 %, and the desired precision was set at 2 %. The sample size needed was 279, rounded to 300. For Vinh Long, a sample size of 338 was obtained, since more individuals were willing to participate. The surveys were conducted in the listed hotspots in each province , in which the number of MSM was estimated. The sample size in each province was stratified based on the estimated size of MSM population in each district, then in each hotspot. All interviewers, medical technicians, and physicians attended a three-day training course specific for conducting the study. Informed consent was obtained prior to face-to-face interviews to collect data on sociodemographic characteristics, sexual identity, sexual behaviors, knowledge related to HIV and sexually transmitted infection , history of STIs, alcohol and recreational drug use, and access to HIV/STI intervention programs. After the interview, four ml of blood and 50 ml of urine were collected. Interviews were conducted by health staff or staff with a background in social sciences who were trained to administer the questionnaire. Biological samples were taken by trained phlebotomists according to national protocols. HIV testing was performed using ELISA and a rapid test . All specimens were tested at provincial AIDS centers. Syphilis was screened using RPR at the AIDS centers. Positive specimens were transported to the Pasteur Institute in Hochiminh City for further confirmation by the Treponema pallidum haemagglutination assay . If positive for both tests, the specimen was considered positive for syphilis. Due to limited funding, syphilis testing was only performed in seven provinces . Neisseria gonorrhoeae and Chlamydia trachomatis were tested by PCR at the PIHCM for only six provinces . The test results were returned to the participants through local voluntary HIV counseling and testing clinics. Men infected with syphilis, NG, and/or CT were referred to local STI centers for free treatment according to national STI treatment syndrome guidelines .
HIV-positive individuals were referred to local outpatient clinics. All interview answer sheets were checked by the interviewers for any missing information, then sent to the supervisors for futher checking before being sent to PIHCM. Interview answer sheets were stored in locked cabinets in the Provincial AIDS Centers and sent to PIHCM. Data were entered using Epi-Data version 3.1 , and all statistical analyses were carried out using Stata version 13.0 . Frequency distributions and percentages were used to describe the HIV infection rate and several qualitative variables. Mean, median and variance were estimated for quantitative continuous variables. These parameters were also used to clean data before further analysis. To partially reduce the effect of temporal relationships between HIV and risk behaviors, those who had been tested for HIV previously and knew they were HIV-positive were removed from the univariate and multivariate analyses, because they might have altered their risk behaviors, and this could possibly cause an inverse association if binary logistic regression analysis was used. Potential covariates were first identified in the existing literature or by subjective prior knowledge plus those variables with p values of ≤0.25 in univariate analysis, and were entered in the full model. Backward elimination was used. Any variable which had a p value over 0.05 was removed from the model. A log likelihood ratio test was performed to compare the “bigger” and “reduced” models. If the log likelihood ratio test gave a p value of ≤0.05, the corresponding variable was retained in the model. The procedure was repeated until no other variables in the model yielded p values of >0.05. The final estimates were also adjusted for cluster effects . The median number of male oral sex partners in the past 3 months was two, while more than one-third of participants reported having 2–4 male anal sex partners in the past three months. The majority of participants were unmarried, and 89.8 % engaged in sex with male partners, but 30.7 % also had sex with females/girl-friends. Few had engaged in sex with a foreigner in the past 12 months.
We found that 49.2 % of those who had ever engaged in sex with a foreigner had ever had transactional sex with male or female clients. Additionally, 24.9 % of those who never engaged in sex with a foreigner ever had transactional sex with male or female clients . One-fourth had had sex with male clients, and 10.4 % had had sex with a male sex worker in the past 12 months. Only 43.5 % had consistently used condoms with any anal sex partners, and 22.7 % never used condoms. Unprotected anal intercourse was slightly higher among unmarried MSM than ever-married MSM . Participants also engaged in sex with their wives/cohabiting partners or female sex workers in the past 12 months, and female clients in the past three months. The rate of consistent condom use with female sex workers was 68.4 %. Lubricant was also used by almost 40 % for anal sex with either males or females .In univariate analysis, HIV infection was more prevalent among older MSM,grow benches those residing in the southeastern provinces , small businessmen/vendors or freelance singers/barbers, those reporting having a religion, ever having sex with a foreigner, consuming alcohol on a daily basis, ever using recreational drugs , and those who thought that they were likely or very likely to be infected with HIV. HIV was less prevalent among those who had higher education levels, and/or never or only sometimes consumed alcohol immediately before having sex. In multivariate analysis, 10 factors were associated with HIV in the final model, including having ever married, having a religion, exclusively/frequently receptive, engaging in sex with a foreigner in past 12 months, consuming alcohol before anal sex in the past 3 months, using condoms during anal sex in the past three months, ever using recreational drugs, using amphetamine-type stimulants /heroin, perceiving oneself to be likely/very likely to be infected, and testing positive for syphilis. When age was increased by one year , the risk of HIV infection increased by 13 % . HIV infection was higher among MSM who had a religion , ever engaged in anal sex with a foreigner , and/or were syphilis-seropositive . Compared with those who had never used recreational drugs, those who reported previously but no longer using , currently inhaling/swallowing drugs , or currently injecting drugs were at significantly increased risk of HIV. When the drug use route was replaced by types of drug in the final model, compared with those who had never used recreational drugs, those who reported using ATS or heroin were at a higher risk of HIV infection. Moreover, MSM who thought that they were likely or very likely to be infected with HIV were at a higher risk of HIV infection.
MSM who had ever married , were exclusively or frequently receptive , sometimes consumed alcohol immediately before having sex , and/or frequently used condoms during anal sex in the past three months were less likely to be infected with HIV. The observed prevalence of HIV among MSM in the eight provinces was low compared with other provinces in Vietnam [>5 % in Hanoi, Hochiminh City, Can Tho and An Giang ], except for Dong Nai. The prevalence of HIV in the southwestern provinces was lower than that observed in southeastern provinces, including Dong Nai . Dong Nai borders with Hochiminh City, which has amongst the highest prevalence of HIV in Vietnam in all high-risk groups, including those who inject drugs, MSM, and female sex workers. Previous studies among MSM in Vietnam were carried out in urban populations, whereas our study was conducted in rural or small urban areas, except for Dong Nai which is an industrial province where HIV prevalence may be lower. The prevalence of HIV in the current study, 2.6 %, was lower than in other countries, including 13.6 % in Brazil, 12.9 % in northern Thailand, and 4.8 % in Beijing, China. Several correlates of HIV infection were identified in this study. Increasing age was found to be correlated with a higher likelihood of HIV infection, perhaps due to cumulative exposure, as was observed in studies in Malawi, Namibia, and Botswana and China . Ever being married was associated with a lower likelihood of HIV, similar to that observed in China; unmarried and homosexual MSM who did not have female sex partners were six-fold more likely to be infected with HIV compared to married or non-homosexual MSM with a female partner. Both that study and ours found that unprotected anal intercourse among married MSM was lower than among those who had never married. The association between having a religion and HIV infection found in this study might be due to infected individuals seeking consolation with religion. However, it is possible that people may believe that their destinies are decided by God and therefore take fewer precautions. It has been shown that personal sexual behaviors and cultures are sometimes related to religion. Hence, education about HIV transmission and prevention should be discussed with religious leaders so they can deliver appropriate messages to MSM and their partners or families. Recreational drug use, especially injecting, was shown to be highly associated with HIV, consistent with a number of other studies. Drug injection was associated with a higher risk of HIV than inhalation, smoking, or swallowing drugs. The fact that those who had previously but no longer used drugs had higher rates of HIV infection suggests either under-reporting current drug use or quitting drug use when learning they were HIV-positive. The risk of HIV infection was different according to drug used: cannabis , ATS , and heroin . Receptive anal intercourse was found to be an important risk factor for sexual HIV transmission in several studies. However, in our study, receptive anal intercourse was associated with a lower likelihood of HIV infection than for those who were exclusively or frequently insertive. This could be partly explained by a higher rate of recreational drug use in the “insertive” group than the “receptive” group in our study. Although a low proportion of MSM engaged in sex with foreigners, this was significantly associated with a higher risk of HIV infection.