Cyprian Wejnert

HIV Infection and Awareness among Men Who Have Sex with Men–20 Cities, United States, 2008 and 2011

Over half of HIV infections in the United States occur among men who have sex with men (MSM). Awareness of infection is a necessary precursor to antiretroviral treatment and risk reduction among HIV-infected persons. We report data on prevalence and awareness of HIV infection among MSM in 2008 and 2011, using data from 20 cities participating in the 2008 and 2011 National HIV Behavioral Surveillance System (NHBS) among MSM. Venue-based, time-space sampling was used to recruit men for interview and HIV testing. We analyzed data for men who reported ≥1 male sex partner in the past 12 months. Participants who tested positive were considered to be aware of their infection if they reported a prior positive HIV test. We used multivariable analysis to examine differences between results from 2011 vs. 2008. HIV prevalence was 19% in 2008 and 18% in 2011 (p = 0.14). In both years, HIV prevalence was highest among older age groups, blacks, and men with lower education and income. In multivariable analysis, HIV prevalence did not change significantly from 2008 to 2011 overall (p = 0.51) or in any age or racial/ethnic category (p>0.15 in each category). Among those testing positive, a greater proportion was aware of their infection in 2011 (66%) than in 2008 (56%) (p<0.001). In both years, HIV awareness was higher for older age groups, whites, and men with higher education and income. In multivariable analysis, HIV awareness increased from 2008 to 2011 overall (p<0.001) and for all age and racial/ethnic categories (p<0.01 in each category). In both years, black MSM had the highest HIV prevalence and the lowest awareness among racial/ethnic groups. These findings suggest that HIV-positive MSM are increasingly aware of their infections.

Estimating the Number of Persons Who Inject Drugs in the United States by Meta-Analysis to Calculate National Rates of HIV and Hepatitis C Virus Infections

Background Injection drug use provides an efficient mechanism for transmitting bloodborne viruses, including human immunodeficiency virus (HIV) and hepatitis C virus (HCV). Effective targeting of resources for prevention of HIV and HCV infection among persons who inject drugs (PWID) is based on knowledge of the population size and disparity in disease burden among PWID. This study estimated the number of PWID in the United States to calculate rates of HIV and HCV infection. Methods We conducted meta-analysis using data from 4 national probability surveys that measured lifetime (3 surveys) or past-year (3 surveys) injection drug use to estimate the proportion of the United States population that has injected drugs. We then applied these proportions to census data to produce population size estimates. To estimate the disease burden among PWID by calculating rates of disease we used lifetime population size estimates of PWID as denominators and estimates of HIV and HCV infection from national HIV surveillance and survey data, respectively, as numerators. We calculated rates of HIV among PWID by gender-, age-, and race/ethnicity. Results Lifetime PWID comprised 2.6% (95% confidence interval: 1.8%–3.3%) of the U.S. population aged 13 years or older, representing approximately 6,612,488 PWID (range: 4,583,188–8,641,788) in 2011. The population estimate of past-year PWID was 0.30% (95% confidence interval: 0.19 %–0.41%) or 774,434 PWID (range: 494,605–1,054,263). Among lifetime PWID, the 2011 HIV diagnosis rate was 55 per 100,000 PWID; the rate of persons living with a diagnosis of HIV infection in 2010 was 2,147 per 100,000 PWID; and the 2011 HCV infection rate was 43,126 per 100,000 PWID. Conclusion Estimates of the number of PWID and disease rates among PWID are important for program planning and addressing health inequities.

Statistical methods for the analysis of time-location sampling data.

Time–location sampling (TLS) is useful for collecting information on a hard-to-reach population (such as men who have sex with men [MSM]) by sampling locations where persons of interest can be found, and then sampling those who attend. These studies have typically been analyzed as a simple random sample (SRS) from the population of interest. If this population is the source population, as we assume here, such an analysis is likely to be biased, because it ignores possible associations between outcomes of interest and frequency of attendance at the locations sampled, and is likely to underestimate the uncertainty in the estimates, as a result of ignoring both the clustering within locations and the variation in the probability of sampling among members of the population who attend sampling locations. We propose that TLS data be analyzed as a two-stage sample survey using a simple weighting procedure based on the inverse of the approximate probability that a person was sampled and using sample survey analysis software to estimate the standard errors of estimates (to account for the effects of clustering within the first stage [locations] and variation in the weights). We use data from the Young Men’s Survey Phase II, a study of MSM, to show that, compared with an analysis assuming a SRS, weighting can affect point prevalence estimates and estimates of associations and that weighting and clustering can substantially increase estimates of standard errors. We describe data on location attendance that would yield improved estimates of weights. We comment on the advantages and disadvantages of TLS and respondent-driven sampling.

HIV Infection and HIV-Associated Behaviors Among Persons Who Inject Drugs — 20 Cities, United States, 2015

In the United States, 9% of human immunodeficiency virus (HIV) infections diagnosed in 2015 were attributed to injection drug use (1). In 2015, 79% of diagnoses of HIV infection among persons who inject drugs occurred in urban areas (2). To monitor the prevalence of HIV infection and associated behaviors among persons who inject drugs, CDCs National HIV Behavioral Surveillance (NHBS) conducts interviews and HIV testing in selected metropolitan statistical areas (MSAs) (3). The prevalence of HIV infection among persons who inject drugs in 20 MSAs in 2015 was 7%. In a behavioral analysis of HIV-negative persons who inject drugs, an estimated 27% receptively shared syringes and 67% had condomless vaginal sex in the previous 12 months. During the same period, 58% had tested for HIV infection and 52% received syringes from a syringe services program. Given the increased number of persons newly injecting drugs who are at risk for HIV infection because of the recent opioid epidemic (2,4), these findings underscore the importance of continuing and expanding health services, HIV prevention programs, and community-based strategies, such as those provided by syringe services programs, for this population.

Network analysis among HIV-infected young black men who have sex with men demonstrates high connectedness around few venues.

Background Network analysis is useful for understanding sexual transmission of HIV and other sexually transmitted infections. We conducted egocentric and affiliation network analysis among HIV-infected young black men who have sex with men (MSM) in the Jackson, Mississippi, area to understand networks and connectedness of this population. Methods We interviewed 22 black MSM aged 17 to 25 years diagnosed as having HIV in 2006 to 2008. Participants provided demographic and geographic information about each sex partner during the 12 months before diagnosis and identified venues where they met these partners. We created affiliation network diagrams to understand connectedness of this population and identify venues that linked participants. Results The median number of partners reported was 4 (range, 1–16); a total of 97 partners (88 of whom were male) were reported. All but 1 participant were connected through a network of venues where they had met partners during the 12 months before diagnosis. Three venues were named as places for meeting partners by 13 of 22 participants. Participants reported having partners from all regions of Mississippi and 5 other states. Conclusions HIV-infected young black MSM in this analysis were linked by a small number of venues. These venues should be targeted for testing and prevention interventions. The pattern of meeting sex partners in a small number of venues suggests densely connected networks that propagate infection. This pattern, in combination with sexual partnerships with persons from outside Jackson, may contribute to spread of HIV and other sexually transmitted infections into or out the Jackson area.

Trends in condom use among MSM in the United States: the role of antiretroviral therapy and seroadaptive strategies.

Objective:Evaluate changes in condomless anal sex at last sex among men who have sex with men (MSM) and assess if these changes are associated with the adoption of serosorting and biomedical prevention. Design:The National HIV Behavioral Surveillance is a crosssectional survey done in up to 21 cities in 2005, 2008, 2011 and 2014. Methods:MSM were recruited through venue-based sampling. Among men reporting at least one male partner, we evaluated changes in condomless anal sex at last sex with a partner with (1) HIV-concordant (proxy for serosorting) or (2) HIV-discordant (discordant/unknown) status. We hypothesized that if concordant condomless sex was increasing while discordant was stable/declining, the increases could be driven by more men attempting to serosort. We used generalized estimating equations assuming a Poisson distribution and robust variance estimator to explore whether temporal changes in the outcomes varied by selected characteristics. We also assessed changes in condomless anal sex by antiretroviral therapy (ART) use among HIV-positive MSM. Results:Among 5371 HIV-positive MSM, there were increases in concordant (19% in 2005 to 25% in 2014, P < 0.001) and discordant condomless sex (15 to 19%, P < 0.001). The increases were not different by ART use. Among 30 547 HIV-negative MSM, concordant (21 to 27%, P < 0.001) and discordant condomless sex (8 to 13%, P < 0.001) increased. Conclusion:Our data suggest that condom use decreased among MSM and that the trends are not explained by serosorting or ART. Promotion of condoms and increased access to preexposure prophylaxis are vital to ensure that the benefits of ART in reducing transmission of HIV are not undermined.

Assessing the Assumptions of Respondent-Driven Sampling in the National HIV Behavioral Surveillance System among Injecting Drug Users

Several assumptions determine whether respondent-driven sampling (RDS) is an appropriate sampling method to use with a particular group, including the population being recruited must know one another as members of the group (i.e., injection drug users [IDUs] must know each other as IDUs) and be networked and that the sample size is small relative to the overall size of the group. To assess these three assumptions, we analyzed city-specific data collected using RDS through the US National HIV Behavioral Surveillance System among IDUs in 23 cities. Overall, 5% of non-seed participants reported that their recruiter was “a stranger.” 20 cities with multiple field sites had ≥1 cross-recruitment, a proxy for linked networks. Sample sizes were small in relation to the IDU population size (median = 2.3%; range: 0.6%- 8.0%). Researchers must evaluate whether these three assumptions were met to justify the basis for using RDS to sample specific populations.

Increases in HIV Testing among Men Who Have Sex with Men — National HIV Behavioral Surveillance System, 20 U.S. Metropolitan Statistical Areas, 2008 and 2011

In 2011, 62% of estimated new HIV diagnoses in the United States were attributed to male-to-male sexual contact (men who have sex with men, MSM); 39% of these MSM were black or African American. HIV testing, recommended at least annually by CDC for sexually active MSM, is an essential first step in HIV care and treatment for HIV-positive individuals. A variety of HIV testing initiatives, designed to reach populations disproportionately affected by HIV, have been developed at both national and local levels. We assessed changes in HIV testing behavior among MSM participating in the National HIV Behavioral Surveillance System in 2008 and 2011. We compared the percentages tested in the previous 12 months in 2008 and 2011, overall and by race/ethnicity and age group. In unadjusted analyses, recent HIV testing increased from 63% in 2008 to 67% in 2011 overall (P<0.001), from 63% to 71% among black MSM (P<0.001), and from 63% to 75% among MSM of other/multiple races (P<0.001); testing did not increase significantly for white or Hispanic/Latino MSM. Multivariable model results indicated an overall increase in recent HIV testing (adjusted prevalence ratio [aPR] = 1.07, P<0.001). Increases were largest for black MSM (aPR = 1.12, P<0.001) and MSM of other/multiple races (aPR = 1.20, P<0.001). Among MSM aged 18–19 years, recent HIV testing was shown to increase significantly among black MSM (aPR = 1.20, P = 0.007), but not among MSM of other racial/ethnic groups. Increases in recent HIV testing among populations most affected by HIV are encouraging, but despite these increases, improved testing coverage is needed to meet CDC recommendations.

Early Linkage to HIV Care and Antiretroviral Treatment among Men Who Have Sex with Men — 20 Cities, United States, 2008 and 2011

Early linkage to care and antiretroviral (ARV) treatment are associated with reduced HIV transmission. Male-to-male sexual contact represents the largest HIV transmission category in the United States; men who have sex with men (MSM) are an important focus of care and treatment efforts. With the release of the National HIV/AIDS Strategy and expanded HIV treatment guidelines, increases in early linkage to care and ARV treatment are expected. We examined differences in prevalence of early linkage to care and ARV treatment among HIV-positive MSM between 2008 and 2011. Data are from the National HIV Behavioral Surveillance System, which monitors behaviors among populations at high risk of HIV infection in 20 U.S. cities with high AIDS burden. MSM were recruited through venue-based, time-space sampling. Prevalence ratios comparing 2011 to 2008 were estimated using linear mixed models. Early linkage was defined as an HIV clinic visit within 3 months of diagnosis. ARV treatment was defined as use at interview. Prevalence of early linkage to care was 79% (187/236) in 2008 and 83% (241/291) in 2011. In multivariable analysis, prevalence of early linkage did not differ significantly between years overall (P = 0.44). Prevalence of ARV treatment was 69% (790/1,142) in 2008 and 79% (1,049/1,336) in 2001. In multivariable analysis, ARV treatment increased overall (P = 0.0003) and among most sub-groups. Black MSM were less likely than white MSM to report ARV treatment (P = 0.01). While early linkage to care did not increase significantly between 2008 and 2011, ARV treatment increased among most sub-groups. Progress is being made in getting MSM on HIV treatment, but more efforts are needed to decrease disparities in ARV coverage.

Increases in Recent HIV Testing Among Men Who Have Sex With Men Coincide With the Centers for Disease Control and Prevention's Expanded Testing Initiative

According to National HIV Behavioral Surveillance system data, human immunodeficiency virus (HIV) testing increased among gay, bisexual, and other men who have sex with men from 2008 to 2011 in cities funded by the Centers for Disease Control and Preventions Expanded Testing Initiative, suggesting that focused HIV testing initiatives might have positive effects.