High human immunodeficiency virus type 1 seroprevalence in men who have sex with men in Buenos Aires, Argentina: risk factors for infection

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1 International Epidemiological Association 2003 Printed in Great Britain International Journal of Epidemiology 2003;32: DOI: /ije/dyg104 High human immunodeficiency virus type 1 seroprevalence in men who have sex with men in Buenos Aires, Argentina: risk factors for infection Maria de los Angeles Pando, 1 Sergio Maulen, 2 Mercedes Weissenbacher, 1 Rubén Marone, 2 Ricardo Duranti, 2 Liliana Martínez Peralta, 1 Horacio Salomón, 1 Kevin Russell, 3 Monica Negrete, 3 Sergio Sosa Estani, 1 Silvia Montano, 3 José L Sanchez 3 and Maria Mercedes Ávila 1 Accepted 9 January 2003 Objective Methods To determine human immunodeficiency virus (HIV) seroprevalence in a sample of men who have sex with men (MSM) in Buenos Aires City and to identify risk factors associated with HIV type 1 infection. Participants were invited to receive HIV counselling and testing at NEXO (a gay non-governmental organization) by means of informative leaflets distributed in gay nightclubs, porno cinemas, gymnasiums, and in the streets. During the encounter, the study was explained by a trained social worker and individuals were invited to volunteer for the study. Diagnosis of HIV was performed using two screening tests and Western Blot assay was used as confirmatory. Results Human immunodeficiency virus was detected in 96 (13.8%; 95% CI: ) of 694 MSM. Fourteen (14.6%) of the 96 HIV-positive MSM were already aware of their HIV serostatus. In univariate analysis, HIV-1 infection (odds ratio [OR] 1.5) was found to be associated with older age (30 39 years), being unemployed, a previous sexually transmitted disease (STD) history, and having an HIV-positive partner. Cocaine consumption and irregular use of condoms with occasional partners were also found to be risk factors. In multivariate logistic regression analysis, being unemployed (OR = 3.42; 95% CI: ) and having an HIVpositive partner (OR = 2.67; 95% CI: ) remained significant risk factors. Discussion Keywords The high HIV-1 prevalence observed suggests an urgent need for implementation of effective prevention campaigns. This represents the first cross-sectional epidemiological study of HIV among the high-risk group of MSM in Argentina. HIV-1, MSM, epidemiology, risk factors, Argentina Presently, the human immunodeficiency virus (HIV) pandemic still remains as the leading cause of deaths in terms of sexually transmitted diseases (STD). Virtually 40 million people worldwide are currently living with HIV, out of which 95% live in 1 National Reference Center for AIDS, Buenos Aires, Argentina. 2 Nexo NGO, Buenos Aires, Argentina. 3 US Naval Medical Research Center Detachment (NMRCD), Lima, Peru. Correspondence: Dr Maria Mercedes Avila, Centro Nacional de Referencia para el SIDA. Departamento de Microbiología, Parasitología e Inmunología. Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Piso 11, C1121ABG, Buenos Aires. mavila@fmed.uba.ar less-developed countries. 1 Most data on the HIV epidemic in Argentina are based on notified AIDS cases, and there is little data on cases of HIV infection. Acquired immunodeficiency syndrome (AIDS) cases have been increasing in Argentina since 1982, when the first case was detected. During the past 20 years, AIDS cases have been reported and have died. More than 65% of HIV infections are concentrated in Buenos Aires, the capital city, and its metropolitan area. Sexual transmission is considered a very important mode of HIV spread, representing nearly 80% of the total AIDS cases reported in the country. Heterosexual transmission has been the primary risk factor for women over the last 5 years. Though no conclusive 735

2 736 INTERNATIONAL JOURNAL OF EPIDEMIOLOGY data on HIV infection are currently available for the population as a whole, it is estimated that individuals (prevalence: 0.37%) are infected with HIV-1. Over the last 4 years, most new cases of AIDS have appeared in the poorest and least educated parts of the population, as a consequence of lack of information on prevention of STD. Acquired immunodeficiency syndrome in children associated with vertical transmission represents 7% of the total AIDS cases in Argentina. 2 Argentina is the second country in the region as regards total notified AIDS cases. Brazil has the highest total with more than cases, then Argentina, followed by Chile (3740 cases), Uruguay (1719 cases), Paraguay (469 cases), and Bolivia (331 cases). The UNAIDS organization estimated an HIV prevalence rate of 0.7% in adults (15 49 years) for both Brazil and Argentina. 3 Different research studies have shown that unprotected anal intercourse carries an especially high risk of HIV transmission for the receptive partner. This risk is several times higher if compared with unprotected vaginal intercourse with an HIVinfected partner. 4 6 The high prevalence of HIV/AIDS cases observed in men who have sex with men (MSM) indicates that this is a very vulnerable population. 7 9 According to data from the National AIDS Programme, there has been a change in HIV epidemiology. At the beginning of the epidemic ( ) the MSM population represented 60% of those who died or are living with AIDS, whereas they now represent 26% of the total. However, when absolute numbers are considered, this diminishing trend is not clearly observed. 2 Previous research assessed HIV prevalence in MSM in Argentina All these studies were based on samples obtained from people who spontaneously sought assistance, including those who sought clinical care. These studies are not representative of the gay population and should not be taken as reference for control programmes. There have been no previous studies of HIV risk behaviour among MSM in Argentina. Moreover, no focused and continuous HIV/AIDS prevention programmes have been implemented for this highly vulnerable group. Patterns of same sex activity, sex trade, numerous casual partners, and alcohol or drug use are suspected to be common practices in the MSM population. The present study, conducted during , examines the HIV prevalence in a gay population in the Buenos Aires metropolitan area. We examined risk factors potentially associated with HIV type 1 infection and suggest potential future areas of prevention that might be addressed. Methods Participants, counselling session, and questionnaire Men who have sex with men, who were 18 years, from Buenos Aires were included in the study from March 2000 through March Individuals with previous HIV positive status were not excluded. Participants were invited to receive HIV counselling and testing by means of informative leaflets which were distributed in gay nightclubs, porno cinemas, gymnasiums, and on the streets as well as in NEXO (a gay non-governmental organization [NGO]). The leaflets offered counselling, testing, and information on HIV/AIDS. Participants were referred to NEXO. During these encounters, the study was explained by trained social workers and individuals were invited to participate. Nearly all the participants (98%) agreed to participate in the study. Informed consent and clinical-epidemiological questionnaire data were obtained in a confidential manner. The questionnaire, administered by trained interviewers, was used to obtain information on demographic characteristics (age, nationality, educational level, and employment) and current sexual practices. Different sexual practices and pattern of current condom use with any partner (occasional, steady or foreigners, men or women) were also assessed. Condom use was regarded as irregular when it was used sometimes, never, or occasionally. The questionnaire also addressed the use of drugs, other STD, and sexual relations with foreigners (either past or present). Previous HIV testing and current alcohol consumption were also registered. The US NMRCD IRB approved the study protocol. Blood sample collection, HIV diagnosis, and post-test counselling A sample of anticoagulated blood was collected in sterile fashion for determination of HIV infection. The samples were sent to the laboratory of the National Reference Centre for AIDS (CNRS) and were analysed by means of ELISA and agglutination techniques (GENSCREEN Plus HIV AgAb, BIORAD; Serodia HIV 1 2, FUJIREBIO). Samples that were positive or indeterminate were subsequently confirmed by Western Blot (Novapath HIV-1, Immunoblot, BIORAD). The HIV test result was linked to the questionnaire by a numeric code that preserved confidentiality and anonymity. After blood collection, volunteers were scheduled to return in 2 weeks time to receive their serology results and post-test counselling. The majority (667, 96.2%) returned for a second interview to obtain the HIV test result, post-test counselling, and service referrals. All those participants who were found to be HIV-positive recevied another appointment for a new blood sample to be taken. On that same visit, viral load (bdna, Chiron) and CD4 count (Coulter EPICS XL, System II) were offered. Based on these results, all HIV-positive individuals were referred to an infectious disease clinic. Statistical analysis Associations between HIV antibody status, demographic characteristics, and behaviours were examined using χ 2 analysis. Multivariate analysis of the association of HIV antibody status with selected covariates was conducted using multiple logistic regression. The covariates included were those significantly associated with HIV antibody status by univariate analysis (i.e. P 0.05). Results Study population characteristics A total of 694 men (mean age: 30.9 ± 9.0 years; range 18 66) reporting same-sex partners constituted the study sample population. Table 1 shows general characteristics of the study group. This population had a middle high level of education and most of them were employed in professional positions. Most participants were Argentinian and lived in Buenos Aires City or its surrounding areas. Approximately 35% of respondents reported that they had sex with foreigners, mainly from the US, Latin America, and Europe. Only 11 (1.6%) participants declared themselves to be sex workers, whereas 36 (5.3%) reported that they had exchanged sex for money (n = 34), drugs (n = 9), or food (n = 6) occasionally during their lifetime.

3 RISK FACTORS FOR HIV-1 IN ARGENTINA 737 Table 1 General characteristics of 694 men who have sex with men, Buenos Aires, Argentina Total, n (%) Variables (n = 694) Age group (years) (4.5) (47.4) (33.9) (9.2) (5.0) Formal education level Primary school 33 (4.7) High school 333 (48.0) University 328 (47.3) Employment status Employed 593 (85.4) Unemployed 101 (14.6) Sex workers (SW) 11 (1.6) Nationality Argentinean 656 (94.5) Latin American 20 (2.8) Other 18 (2.7) Sex with foreigners 246 (35.4) Exchanged sex for money, drugs, or food (do not regard themselves as 36 (5.3) sex workers) (n = 683) History of STD a 171 (24.6) Previous HIV b test n=410 (59.1%) Positive 14 (3.4) Negative 396 (96.6) Use of drugs 126 (18.2) Alcohol consumption Never 287 (41.4) 1/week 300 (43.2) 2 7 per week 107 (15.4) No. of partners/week (77.7) (17.1) 5 36 (5.2) Condom use with casual partner Regular 326 (47.0) Irregular 368 (53.0) Having a steady partner 371 (53.5) Condom use with steady partner (n = 371) Regular 144 (38.8) Irregular 227 (61.2) Partner with previous HIV test (n = 160) (43.1%) Positive 53 (33.1) Negative 107 (66.9) a Sexually transmitted disease. b Human immunodeficiency virus. A prior history of STD was reported by 171 (24.6%) of participants. Gonorrhoea was the most frequently reported STD (n = 73, 10.5% participants), followed by syphilis (n = 48, 6.9%), herpes (n = 36, 5.2%), condyloma (n = 19, 2.7%), urethritis (n = 17, 2.4%), and chlamydia (n = 4, 0.6%). Previous HIV serology (being tested as far back as 2 years before this study), was reported by 410 (59.1%) participants. Among the latter, 14 (3.4%) knew that they were HIVpositive. In all, 126 (18.2%) subjects reported previous drug use, but only 3 reported intravenous use. Marihuana was the most frequently used drug (113 [16.3%]), followed by inhalational cocaine use (45 [6.5%]). Moderate alcohol consumption ( 2 7 drinks per week) was declared by 107 (15.4%) of subjects. A majority of subjects reported not having more than one sex partner per week and only a few reported more than five sex partners (as many as 20 weekly in a few cases). More than half of them reported having a steady partner, among whom 160 had undergone a previous HIV test and 53 were HIV-positive. Condoms were irregularly used by most of the participants, being less frequently used among those with a steady partner. HIV seroprevalence and risk factors associated with HIV infection A total of 96 (13.8%; 95% CI: ) subjects tested HIVpositive. Fourteen (14.6%) of the 96 were already aware of their HIV serostatus and were already receiving medical support at the time of the study. Among those who reported that previous testing for HIV had given negative results, 10.8% (43 of 396) were now HIV-positive, and among those who did not report previous testing, 13.7% (39 of 284) tested HIV-positive. Table 2 shows the HIV prevalence according to different risk factors. Prevalence of infection varied significantly across age groups. The older age groups, specifically those who were years, showed the highest rate of infection (OR = 2.64, 95% CI: ). No significant differences in HIV seroprevalence were detected based on education level, nationality, number of sex partners, having a steady partner, or having sex with foreigners. Having exchanged sex for money, drugs, or food and being a sex worker was associated with higher HIV infection though not significantly. Use of drugs was not associated with risk of infection among the 126 participants who declared the use of recreational drugs. However, cocaine use, analysed alone, was significantly associated with an HIV-positive diagnosis (OR = 6.70, 95% CI: ). The univariate analysis to estimate the risk of HIV infection showed an OR 1.5 among those MSM who were unemployed (OR = 2.10, 95% CI: ), those who had a previous history of STD (OR = 2.06, 95% CI: ), syphilis (OR = 3.16, 95% CI: ), condyloma (OR = 2.99, 95% CI: ), and among those who had an HIV-positive partner (OR = 2.57, 95% CI: ). Table 3a shows HIV prevalence associated with the use of condoms. Irregular use of condoms was found to be associated with HIV-1 infection only among those with casual partners (OR = 2.58, 95% CI: ). On the other hand, HIV prevalence was found to be lower among those who regularly used condoms with their steady partner (OR = 0.53, 95% CI: ). Table 3b shows the univariate analysis to identify the association between condom use and other variables. On the one hand, participants who exchanged sex for something were more likely to use condoms (OR = 0.48, 95% CI: ). On the other hand, participants who had low educational level were less likely to use condoms (OR = 2.46, 95% CI: ). Among those who had a steady sex partner (n = 371), when the participant or his partner were infected, the use of condoms was more frequent (OR = 0.28, 95% CI: ),

4 738 INTERNATIONAL JOURNAL OF EPIDEMIOLOGY Table 2 Univariate analysis of human immunodeficiency virus (HIV) prevalence by social characteristics and sexual behaviour practices among 694 men who have sex with men, Buenos Aires, Argentina Variables HIV positive/total HIV seroprevalence % Odds ratio (95% CI) Age group (years) 29 35/ / ( ) / ( ) 50 1/ ( ) Employment status Employed 73/ ( ) Unemployed 23/ Sex workers Yes 3/ ( ) No 93/ Exchanged sex for money, drugs, or food (do not regard themselves as sex workers) (n = 683) Yes 8/ ( ) No 85/ Previously diagnosed STD a Yes 36/ ( ) No 60/ Partner with HIV test result (n = 160) Positive 13/ ( ) Negative 12/ Use of drugs Yes 21/ ( ) No 75/ Type of drugs n = 124 Marijuana 12/ Cocaine 6/ ( ) Marijuana/cocaine 3/ ( ) No. of partners per week / / ( ) 5 7/ ( ) a Sexually transmitted disease. Table 3a Univariate analysis of human immunodeficiency virus (HIV) prevalence by use of condom in 694 men who have sex with men Buenos Aires, Argentina Variables Use of condom HIV positive/total HIV seroprevalence % OR (95% CI) Use of condom with steady partner (n = 371) Regular 30/ Irregular 28/ ( ) Use of condom with casual partner Regular 27/ when they have a steady partner (n = 371) Irregular 31/ ( ) Condom use with HIV positive steady partner Regular 6/ (n = 50) Irregular 7/ ( ) Condom use with HIV negative steady partner Regular 9/ (n = 105) Irregular 3/ ( ) Condom use with unknown HIV-status steady partner Regular 15/ (n = 216) Irregular 18/ ( ) Condom use with casual partner when Regular 11/ they do not have a steady partner (n = 323) Irregular 27/ ( ) but it was less frequent when they had low educational level (OR = 3.33, 95% CI: ). In multivariate logistic regression analysis, being unemployed (OR = 3.42, 95% CI: ) and having an HIV-positive partner (OR = 2.67, 95% CI: ) remained significant risk factors. Discussion This highly educated study sample of MSM was found to be at high risk of HIV infection, as illustrated by the high HIV prevalence (almost 14%). Similarly, a large proportion of MSM were found to engage in unprotected sex practices (more than 50%).

5 RISK FACTORS FOR HIV-1 IN ARGENTINA 739 Table 3b Univariate analysis of use of condom with occasional and steady partner in 694 men who have sex with men, Buenos Aires, Argentina Irregular use of Prevalence Odds ratio Variables condom/total % (95% CI) Use of condom with occasional partner (n = 694) Exchanged sex for money, drugs or food Yes 13/ (do not regard themselves as sex worker) (n = 683) No 349/ ( ) Formal education level Primary school 24/ High school or higher education 344/ ( ) Use of condom with a steady partner (n = 371) HIV previous diagnosis Yes 19/ in volunteer and/or his partner No 208/ ( ) Formal education level Primary school 15/ High school or higher education 212/ ( ) This clearly shows the lack of effect of prevention programmes aimed at this vulnerable population. This research study provided an important opportunity for assessing the status of the HIV epidemic in a sample of MSM frequenting public venues in Buenos Aires City. This represents the first cross-sectional study of HIV seroprevalence conducted exclusively in a MSM population in our country. Other reports on MSM populations in Argentina were based on samples from individuals who spontaneously sought assistance and where the HIV prevalence ranged from 18 to 67% A limitation of our study may be the fact that all participants were recruited through only one gay rights NGO, so our findings may not be representative of other MSM groups. However, recruitment was carried out by means of leaflets distributed at different sites in the city frequented by MSM and, moreover, as this is the only gay rights NGO which offers HIV counselling and testing, many participants are referred to it by other NGO. The HIV prevalence detected in our MSM population is similar to that observed in large cities of other countries. In New York City, a study carried out during showed that the HIV seroprevalence among 541 MSM aged years was 12.1%. 7,8 In a recent study performed among 651 MSM in Bogota, Colombia, the HIV prevalence was found to be 18.4%, with an increasing prevalence with age. 9 A considerable proportion of the population (96.2%) returned to receive the HIV serology result. Most of MSM who has a positive HIV result (85%) returned to the laboratory to have viral load levels and CD4 cells counts monitored. This positive attitude showed that patients were concerned about their health care. Sexually transmitted diseases proved to be highly associated with HIV-1 infection in this population. The presence of other STD increases the transmissibility of HIV by providing a vulnerable port of entry for the virus and may, in some circumstances, affect the course of HIV disease. Besides, the presence of HIV increases susceptibility to some STD and modifies the presentation, course, complication rate, and response to therapy of some of the other classic infections. 14 In the US, a review of 30 studies performed among patients with syphilis showed that the HIV prevalence ranged from 64.3% to 90.0%, 15 therefore showing the importance of the early diagnosis and treatment of other STD to decrease the risk of HIV transmission. Our study shows the same trend, though not as dramatically as that presented above. The presence of one or more STD doubled the risk of HIV infection (21.1% of HIV infection among STD positive versus 11.5% among STD negative; OR = 2.06, 95% CI: ). It is important to target STD clinics and other primary care settings, where screening and treatment for STD can be combined with HIV prevention efforts. Unprotected anal sex carries a high risk of HIV transmission, especially for the receptive partner. 16 Our results show that condoms were irregularly used by most of the participants (either with a casual or steady partner). When HIV seroprevalence was analysed according to condom use, we observed that it was significantly higher among those who regularly used one with their steady partner (regardless of knowledge of their previous HIV status). Similarly, we found the same trend among MSM who already had an HIV-negative diagnosis. This phenomenon may be the result of a change of attitude based on their assumption of a current infection. On the other hand, those who used condoms irregularly with casual partners were also at higher risk. The regular use of condoms was more frequent among those who were HIV-infected or had an HIV-infected partner. This was most probably due to a change in attitude in relation to their previous awareness that the subject or his partner was infected (60% had a previous HIV test). Being unemployed was also found to be associated with a higher risk of HIV-1 infection. This trend may get worse in the light of the current economic crisis. Moreover, having an HIVpositive partner was also found to significantly increase the risk of HIV-1 infection. There are no data on the overall number of gays in Argentina. Hence, we cannot assume that the population studied is a representative sample of this particular population. Nevertheless, the high HIV prevalence and the associated risk factors observed in this study suggest that prevention programmes targeted at this highly vulnerable population need to be implemented. New NGO, such as NEXO, are on the rise in Buenos Aires, but not in other cities of the country. The economic upheaval, which is often accompanied by widespread unemployment and concomitant use of drugs or alcohol, are factors which lead to HIV spread in all populations, including gays. The results observed in this study identify an MSM sample population that is at high-risk of contracting HIV infection even though they had a high education level. These data merit further research to clearly understand the HIV risks. Seroincidence studies,

6 740 INTERNATIONAL JOURNAL OF EPIDEMIOLOGY where the incidence of HIV-1 infection is monitored by means of follow-up of a cohort as well as by detuned assay (The Serologic Algorithm for Recent HIV Seroconversion 17 is currently being used in order to better evaluate the dynamics of transmission in this population). Data obtained during the course of these studies will allow us to assess more reliably trends in HIV infection in this group and establish effective prevention programmes to curtail the HIV epidemic. Acknowledgements This study was partially supported by the US Naval Medical Research Center Detachment (NMRCD)-Lima, Peru (Work Unit 62787A S17 B0002), through a grant with the Pan American Health Organization (PAHO) and by PICT , Argentina. The opinions and assertions contained herein are the private ones of the signing authors. References 1 AIDS epidemic update. UNAIDS. Joint United Nations Programme on HIV/AIDS. July Available at: update/report_dec01. Last accessed 20 November Boletin sobre el SIDA en la Argentina. Ministerio de Salud. Unidad Coordinadora Ejecutora VIH/SIDA y ETS. August UNAIDS. Report on the Global HIV/AIDS Epidemic. UNAIDS, Leynaert B, Downs AM, de Vincenzi I. Heterosexual transmission of human immunodeficiency virus: variability of infectivity throughout the course of infection. European Study Group on Heterosexual Transmission of HIV. Am J Epidemiol 1998;148: Padian NS, Shiboski SC, Glass SO, Vittinghoff E. Heterosexual transmission of human immunodeficiency virus (HIV) in northern California: results from a ten-year study. Am J Epidemiol 1997;146: Misegades L, Page-Shafer K, Halperin D, McFarland W. Anal intercourse among young low-income women in California: an overlooked risk factor for HIV? AIDS 2001;15: Koblin BA, Torian LV, Guilin V, Ren L, MacKellar DA, Valleroy LA. High prevalence of HIV infection among young men who have sex with men in New York City. AIDS 2000;14: Valleroy LA, MacKellar DA, Karon JM et al. HIV prevalence and associated risk in young men who have sex with men. JAMA 2000; 284: Mejia A, Ardila H, De la Hoz F, Calderon J, Velandia M. HIV Prevalence Among Men Who Have Sex With Men (MSM), Bogota, Colombia. The first IAS Conference on HIV Pathogenesis and Treatment. July Buenos Aires, Argentina. Poster LB-P Cahn P, Perez H, Casiro A, Scaglione C, Muchinik G. Análisis de la demanda espontanea de un consultorio externo de SIDA en la Ciudad de Buenos Aires. Medicina 1998;48: Boxaca M, Belli L, Casco R et al. Anti-HIV Antibodies in Outpatients From a Sexually Transmitted Disease Clinic in Buenos Aires City. IV International Conference on AIDS, Stockholm, 6/13 14, Poster 5085, Muchinik G, Fay O, Cahn P et al. HIV Seropositivity in High Risk Groups in Argentina: Future Impact on Heterosexual Transmission. IV International Conference on AIDS, Stockholm, 6/13 14, Poster 5062, Cahn P, Ben G, Bloch C, San Pedro M, Gonzales S, Perez H. Who is Knocking on the Door for HIV Testing: Study of 9959 Cases. XI International Conference on AIDS, Vancouver, 7/7 14, Poster Mo.C.1422, Rein MF. The interaction between HIV and the classic sexually transmitted diseases. Curr Infect Dis Rep 2000;2: Blocker ME, Levine WC, St Louis ME. HIV prevalence in patients with syphilis, United States. Sex Transm Dis 2000;27: UNAIDS. AIDS and Men Who Have Sex With Men. UNAIDS, Technical update. Available at: Last accessed: May Janssen RS, Satten GA, Stramer SL et al. New testing strategy to detect early HIV-1 infection for use in incidence estimates and for clinical and prevention purposes. JAMA 1998,280: International Epidemiological Association 2003; all rights reserved. International Journal of Epidemiology 2003;32: DOI: /ije/dyg214 Commentary: The human immunodeficiency virus/aids epidemic among men who have sex with men in Latin America and the Caribbean: It is time to bridge the gap Carlos F Cáceres 1 and Ron Stall 2 The paper by Pando et al., 1 published in this issue of the International Journal of Epidemiology, underscores the need to 1 School of Public Health, Cayetano Heredia University, Lima, Av. Armendáriz 445, Miraflores, Lima, Peru. ccaceres@upch.edu.pe 2 Prevention Research Branch, Division of HIV/AIDS Prevention IRS, National Center for HIV, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta GA, USA. rstall@cdc.gov focus on the human immunodeficiency virus (HIV) epidemic among men who have sex with men (MSM), which until now has not received attention proportional to its magnitude. The fact that this is the first study of its kind in Argentina also highlights the paucity of sound epidemiological information on which HIV prevention and control in Latin America could be based. Interpretation of this paper might be better achieved if it is put in the context of the larger HIV/AIDS epidemic among