IAS–USA Topics in Antiviral MedicineConference Highlights—Epidemiology and Prevention Volume 19 Issue 2 May/June 2011 HIV Epidemiology and Breakthroughs in Prevention 30 Years Into the AIDS Epidemic Susan P. Buchbinder, MD Thirty years after the first AIDS cases were reported in the United States, the at particularly high risk. In examin- HIV epidemic continues to be heavily concentrated among men who have sex ing drivers of the epidemic in MSM, with men (MSM) in the United States. MSM are heavily impacted throughout numerous studies have shown lower most of the world and are the predominant risk group throughout the levels of reported sexual risk and drug Americas and Western Europe; heterosexuals are the predominant risk group use among black and Latino MSM in sub-Saharan Africa; and injection drug users predominate throughout than among white MSM. These racial Eastern Europe and Southeast Asia. In the United States, blacks and Latinos and ethnic disparities may arise as a continue to be disproportionately affected, despite overall advances in HIV result of differences in background testing and care. The 2011 Conference on Retroviruses and Opportunistic prevalence, patterns of intraracial mix- Infections focused on populations heavily impacted throughout the world: ing, prevalence of sexually transmit- adolescents, women, MSM, and serodiscordant couples. Several presentations ted infections, access to antiretroviral focused on the unique relationship between herpes simplex virus type 2 therapy, and rates of undiagnosed HIV (HSV-2) and HIV-1; although many opportunistic infections increase HIV infection, all of which may drive in- acquisition risk, HSV-2 is likely the only one whose effective prevention or creased rates in black and Latino MSM. treatment could substantially influence HIV infection rates, because of the high Millett and colleagues also present- prevalence and persistence of HSV-2. The 2011 conference also celebrated the ed data from 1214 black and Latino substantial advances made in the use of antiretroviral drugs for prevention of MSM enrolled in the Brothers y Her- HIV acquisition (eg, oral preexposure prophylaxis, topical microbicides) and manos study in New York City, Phila- transmission (eg, antiretroviral therapy). Further progress is also being made delphia, and Los Angeles (Abstract in evaluating other prevention strategies and their rollout, including male 131LB). Overall, 12% were HIV-sero- condoms, male circumcision, and HIV testing and linkage to care. positive and unaware of their infec- tion, with a higher rate among black The US HIV Epidemic the United States who have ever been than Latino men (18% vs 5%, respec- tested for HIV has risen to 45%, and tively; P < .001). Among both groups, Mermin provided an overview of the the proportion of persons with AIDS having a low perceived risk of testing US epidemic and strategies for imple- diagnosed within 12 months of their HIV-seropositive and endorsing the menting high-impact prevention (Ab- first HIV-seropositive test has dropped belief that having sex with men of the stract 19). He reminded the audience to 32%. However, given limited re- same race or ethnicity reduces the risk of the substantial disparities in HIV sources, Mermin called for targeted of HIV acquisition were independently infection, with new infections more prevention strategies based on knowl- associated with being HIV-seroposi- than 40 times more likely to be in men edge of effectiveness, cost, scalability, tive and unaware. Among black MSM, who have sex with men (MSM) than and coverage of affected populations. having disclosed sexual identity to a in other men and women and more Millett further explored the US epi- health care practitioner, having health than 8 times more likely in blacks and demic in MSM, the only risk group insurance, and having fewer than 3 times more likely in Latinos than in in the United States in whom new 3 lifetime HIV tests were also indepen- whites. Tremendous strides have been infections continue to rise (Abstract dently associated with HIV-seroposi- made in prevention, with community- 69). Modeling suggests that even if tive–unaware status. initiated behavior change leading to an MSM and heterosexuals had similar Millett pointed to the need to ad- 89% reduction in the transmission rate numbers of sexual partners and rates dress the misperceived risk of HIV ac- per 100 HIV-infected persons, thereby of unprotected intercourse, incidence quisition, including the risk associated averting an estimated 350,000 new rates in MSM would be higher because with intraracial partnerships. He also HIV infections since the beginning of of higher background prevalence rates, highlighted the responsibility of prac- the epidemic. Through expanded HIV increased risk of anal versus vaginal titioners to offer frequent HIV tests to testing, the proportion of people in sex, and role versatility in which many MSM, as even black MSM who disclose MSM serve both insertive and recep- their risk to health care practitioners tive roles, thereby accelerating trans- and who have health insurance appear Dr Buchbinder is director of the HIV Re- search Section at the San Francisco Depart- mission through partner networks. to be at elevated risk of HIV seroposi- ment of Public Health and associate clinical MSM are disproportionately affect- tivity. Millett also called for multilevel professor of medicine and epidemiology at ed within all racial and ethnic groups, approaches to prevention and treat- the University of California San Francisco. and young black and Latino MSM are ment for MSM, including those using 38 Conference Highlights—Epidemiology and Prevention Volume 19 Issue 2 May/June 2011 individual-, interpersonal-, and struc- study of seroadaptive behavior among sented from a study conducted in Can- tural-level interventions. 1207 men recruited from December ada. Brenner and colleagues reported Heffelfinger and colleagues report- 2007 to October 2008 in San Fran- on the spread of HIV among MSM ed on recent HIV infections among cisco (Abstract 133). Behavioral prac- in Montreal, Canada, from December MSM in 21 high-prevalence US cities tices were evaluated at the individual, 2005 to September 2009 (Abstract enrolled in the 2008 National HIV Be- dyad, and episode levels, and were cat- 1046). HIV sequence data were col- havioral Surveillance System (NHBS) egorized into mutually exclusive prac- lected from surveillance of primary (Abstract 130). Of 6864 evaluable tices based on highest to lowest HIV HIV-1 infections (PHIs) and divided MSM, 4% had new infections, defined transmission risk. Seroadaptation was into unique transmissions, small clus- as having an HIV-seropositive test re- reported consistently by 39% of men, ters (2−4 PHIs), and large clusters sult with a reported last HIV-serone- whereas only 25% reported 100% con- (5−31 PHIs). Large clusters of infec- gative test result within the past 12 dom use, 14% no oral or anal sex, and tion accounted for the fastest grow- months. Independent risk factors for 12% oral sex only. When the unit of ing subepidemic, accounting for 25% recent infection (compared with unin- evaluation was partnerships, 100% of all transmissions in 2005 to 39% fected men) were younger than age 30 condom use was the most common in 2009 (P < .001). The 34% of infec- years; black, non-Hispanic race; His- practice (33%) compared with sero- tions occurring from MSM born out- panic ethnicity; other nonwhite race or adaptation (26%). When the unit of side of Canada were predominantly ethnicity; completing less than a high evaluation was sexual episode, oral sex unique transmission events. Given school education; having no insurance was the most common practice (65% the unique sociodemographic and be- or public insurance; and having had of acts), and anal sex with a condom havioral characteristics of these 3 dif- 2 or more HIV tests in the prior 24 was next most common (16%). Over- ferent types of transmission groups, months. Risk practices were not sta- all, more than 90% of all individuals, prevention strategies may need to be tistically significantly associated with dyads, and episodes used some form targeted differently to reach all 3 sub- recent infection. of safer sex or seroadaptation, suggest- populations of MSM contributing to this This report extends the data report- ing that MSM use several strategies to epidemic. ed by Millett and colleagues about the manage their HIV risk. independent association of sociode- Golden and colleagues presented Populations at High Risk of mographic variables with HIV acqui- data on the differential impact of sero- HIV-1 Acquisition sition risk, in the absence of reported sorting by race among MSM in Seattle, differences in sexual practices or drug Washington (Abstract 1037). In their Youth use. Heffelfinger suggested 3 possible study of 7620 white and black MSM explanations: (1) increased prevalence who received HIV testing at a sexually Pettifor reminded the audience that and sexual mixing patterns within transmitted diseases clinic in Seattle approximately half of all new HIV subgroups; (2) differences in access to from 2006 to 2010, 266 participants infections globally occur in persons care among subgroups; and (3) differ- received a new diagnosis of HIV infec- younger than 25 years, with 35% oc- ential underreporting of risk practices. tion. White and black MSM reported curring in 15- to 24-year-olds (Abstract Regardless of reason, successful, cul- serosorting (unprotected anal sex only 66). There are also marked