Susan Scheer

Decreases in Community Viral Load Are Accompanied by Reductions in New HIV Infections in San Francisco

Background At the individual level, higher HIV viral load predicts sexual transmission risk. We evaluated San Franciscos community viral load (CVL) as a population level marker of HIV transmission risk. We hypothesized that the decrease in CVL in San Francisco from 2004–2008, corresponding with increased rates of HIV testing, antiretroviral therapy (ART) coverage and effectiveness, and population-level virologic suppression, would be associated with a reduction in new HIV infections. Methodology/Principal Findings We used San Franciscos HIV/AIDS surveillance system to examine the trends in CVL. Mean CVL was calculated as the mean of the most recent viral load of all reported HIV-positive individuals in a particular community. Total CVL was defined as the sum of the most recent viral loads of all HIV-positive individuals in a particular community. We used Poisson models with robust standard errors to assess the relationships between the mean and total CVL and the primary outcome: annual numbers of newly diagnosed HIV cases. Both mean and total CVL decreased from 2004–2008 and were accompanied by decreases in new HIV diagnoses from 798 (2004) to 434 (2008). The mean (p = 0.003) and total CVL (p = 0.002) were significantly associated with new HIV cases from 2004–2008. Conclusions/Significance Reductions in CVL are associated with decreased HIV infections. Results suggest that wide-scale ART could reduce HIV transmission at the population level. Because CVL is temporally upstream of new HIV infections, jurisdictions should consider adding CVL to routine HIV surveillance to track the epidemic, allocate resources, and to evaluate the effectiveness of HIV prevention and treatment efforts.

Combination Antiretroviral Therapy and Recent Declines in AIDS Incidence and Mortality

The reasons for recent declines in AIDS incidence and mortality may include advances in treatment, but these may be confounded by earlier declines in the incidence of human immunodeficiency virus (HIV) infection. To determine whether the declines in AIDS and mortality may, in part, stem from wider use of combination antiretroviral therapy, 622 HIV-positive men with well-characterized dates of seroconversion were followed. In this group, combination therapy came into widespread use in only 1996. In a Cox proportional hazards model, the 1996 calendar period was significantly associated with slower progression to AIDS (relative hazard [RH]=0. 19, 95% confidence interval [CI], 0.05-0.69, P=.01) and death (RH=0. 45, 95% CI, 0.21-0.95, P=.04). Declines in incidence of HIV infection, changes in HIV virulence, and end-point underreporting cannot fully explain the decline in AIDS and death in 1996. The introduction of combination antiretroviral therapy as the standard of care may already have had measurable effects.

Effect of highly active antiretroviral therapy on diagnoses of sexually transmitted diseases in people with AIDS

BACKGROUND There has been an increase in high-risk sexual behaviour and sexually transmitted diseases (STD) during the time period when highly active antiretroviral therapy (HAART) became widely available. We examined whether taking HAART increased the risk of acquiring an STD--an epidemiological marker of unsafe sex--in people with AIDS. METHODS We did a computerised match of people in the San Francisco STD and AIDS registries. People with AIDS who were diagnosed before 1999 and alive in November, 1995, or later, were classified as having had an STD after AIDS diagnosis or not having had an STD after AIDS diagnosis. We used a Cox proportional hazards model to see whether use of antiretroviral therapy was associated with acquiring an STD after AIDS, after adjustment for sex, age, race, HIV-1 risk category, and CD4 count at AIDS diagnosis. FINDINGS People with AIDS who had had HAART showed an independent increase in the risk of developing an STD (hazard ratio 4.10; 95% CI 2.84-5.94). Americans of African origin, younger age, and higher CD4 count at AIDS diagnosis were also associated with acquiring an STD after AIDS. The number of people living with AIDS who acquired an STD increased over time from 60 (0.66%) in 1995 to 113 (1.32%) in 1998 (p<0.001). INTERPRETATION We have shown that people on HAART are more likely to develop an STD, an epidemiological marker of unsafe sex. More intensive risk-reduction counselling and STD screening for people with AIDS is needed.

Determinants of enrollment in a preventive HIV vaccine trial: hypothetical versus actual willingness and barriers to participation.

Objective:To compare hypothetical and actual willingness to enroll in a preventive HIV vaccine trial and identify factors affecting enrollment. Methods:Participants previously enrolled in an HIV vaccine preparedness study (VPS) in 8 US cities were invited to be screened for a phase 2 HIV vaccine trial. Demographic and risk characteristics of those enrolling, ineligible, and refusing enrollment were compared using the χ2 or Fisher exact test. Multivariable logistic models were used to identify independent predictors of refusal. Results:Of 2531 high-risk HIV-uninfected former VPS participants contacted for the vaccine trial, 13% enrolled, 34% were ineligible, and 53% refused enrollment. Only 20% of those stating hypothetical willingness during the VPS actually enrolled in this vaccine trial. In multivariate analysis, refusal was higher among African Americans and lower in persons >40 years of age, those attending college, and those with ≥5 partners in the prior 6 months. All racial ethnic groups cited concerns about vaccine-induced seropositivity; African Americans also cited mistrust of government and safety concerns as barriers to enrollment. Conclusions:Steps can be taken to minimize potential social harms and to mobilize diverse communities to enroll in trials. Statements of hypothetical willingness to participate in future trials may overestimate true enrollment.

Neutralization Escape in Human Immunodeficiency Virus Type 1—Infected Long-Term Nonprogressors

Neutralization-escape variants of human immunodeficiency virus type 1 (HIV-1) were sought in persons who had persistent low virus loads and who remained asymptomatic for at least 12-16 years of infection without antiretroviral therapy. Viruses were isolated from 3 persons at two or three time points during the course of infection and were assessed for neutralization by sequential autologous serum samples. Virus neutralization was poor or undetectable with contemporaneous autologous serum but improved with later serum samples for each person. In particular, later isolates resisted neutralization by autologous serum samples that neutralized an earlier isolate. Strain-specific neutralizing antibodies remained detectable for up to 4.2 years without diminishing in titer. The results demonstrate that neutralization-escape variants arise periodically in HIV-1-infected long-term nonprogressors.

Disparities in engagement in care and viral suppression among persons with HIV.

Background:Engagement across the spectrum of HIV care can improve health outcomes and prevent HIV transmission. We used HIV surveillance data to examine these outcomes. Methods:San Francisco residents who were diagnosed with HIV between 2009 and 2010 were included. We measured the characteristics and proportion of persons linked to care within 6 months of diagnosis, retained in care for second and third visits, and virally suppressed within 12 months of diagnosis. Results:Of 862 persons included, 750 (87%) entered care within 6 months of diagnosis; of these, 72% had a second visit in the following 3–6 months; and of these, 80% had a third visit in the following 3–6 months. Viral suppression was achieved in 50% of the total population and in 76% of those retained for 3 visits. Lack of health insurance and unknown housing status were associated with not entering care (P < 0.01). Persons with unknown insurance status were less likely to be retained for a second visit; those younger than 30 years were less likely to be retained for a third visit. Independent predictors of failed viral suppression included age <40 years, homelessness, unknown housing status, and having a single or 2 medical visits compared with 3 visits. Conclusions:Socioeconomic resources and age, not race or gender, are associated with disparities in engagement in HIV care in San Francisco.

Viagra, methamphetamine, and HIV risk: results from a probability sample of MSM, San Francisco.

Objectives: To determine the prevalence and factors of Viagra use in combination with crystal methamphetamine and its association with HIV risk behavior in a probability sample of men who have sex with men (MSM). Study Design: A cross-sectional, random-digit dial telephone survey of MSM in San Francisco conducted between June 2002 and January 2003. Results: Of the 1976 MSM, 13.5% used Viagra alone, 7.1% used methamphetamine without Viagra, 9.6% used Viagra with a mood-altering substance (excluding methamphetamine), and 5.1% used Viagra with methamphetamine. Of the MSM using Viagra with methamphetamine, 57% were HIV-infected and 24% of these men reported serodiscordant unprotected insertive intercourse. Viagra used with methamphetamine was independently associated with a higher risk of serodiscordant unprotected insertive intercourse, serodiscordant unprotected receptive intercourse, and a recent diagnosis of a sexually transmitted disease. Conclusion: MSM who use Viagra with crystal methamphetamine have high prevalence rates of HIV and engage in HIV risk behaviors.

A new trend in the HIV epidemic among men who have sex with men, San Francisco, 2004-2011.

Background:In San Francisco, men who have sex with men (MSM) have historically comprised 90% of the HIV epidemic. It has been suggested that given the ongoing HIV transmission among this population, there is the possibility of a high-level endemic of HIV into the future. We report on the possibility of another phase in the HIV epidemic among MSM in San Francisco. Methods:Behavioral surveillance systems monitor HIV prevalence, HIV incidence, and behaviors among populations at high risk for HIV infection. Among MSM, time–location sampling is used to obtain samples for standardized behavioral surveys, HIV-antibody and incidence testing. We analyzed National HIV Behavioral Surveillance data from MSM sampled in 2004, 2008, and 2011. Results:Three hundred eighty-six, 521, and 510 MSM were enrolled in each of the waves. Only slight changes were seen in demographics over time. We detected significant declines in unrecognized HIV infection and methamphetamine use, a significant increase in HIV testing in the past 6 months, and no changes in HIV prevalence, history of gonorrhea infection, or having multiple sex partners. Among HIV-infected men, current antiretroviral treatment (ART) use seems to have risen from 2008 to 2011. Conclusions:The trends of the last 7 years point to stable HIV prevalence as rising ART coverage results in improving survival coupled with decreasing incidence as ART use achieves viral load suppression at levels more than sufficient to offset ongoing sexual risk behavior. “Treatment as prevention” may be occurring among MSM in San Francisco.

Sexual and Drug Use Behavior Among Women Who Have Sex With Both Women and Men: Results of a Population-Based Survey

Recent HIV/AIDS trends in the United States suggest a relative increase in HIV infections among women attributed to injection drug use or heterosexual contact.1 Although the biological risk of female-to-female sexually transmitted HIV is unknown, it is thought to be much lower than the risk of transmission between men and women, including instances in which a condom is used.2 However, studies focusing on women who have sex with women (WSW) have shown that some subgroups of WSW exhibit high levels of sexual risk behaviors with men as well as unsafe injection drug use.3,4 Thus, if risk assumptions are based on self-reported or presumed sexual identity, possible risks for HIV infection may be underestimated in some subgroups of WSW. Few studies have estimated the proportion of WSW or characterized their behavior in samples representative of the population as a whole. Here we describe sexual and drug use behaviors associated with HIV and other sexually transmitted diseases (STDs) among WSW who took part in a door-to-door, population-based survey of women aged 18 to 29 years. The survey was conducted between April 1996 and January 1998 among residents of low-income neighborhoods in Northern California. Study methods have been described in detail in a previous article.5 Of 2547 women who completed the study, 2229 (88%) reported sex exclusively with men, 189 (7%) reported sex with both men and women, and 16 (1%) reported sex exclusively with women. Of the 7 HIV-positive women, 4 reported only male partners, 2 reported both male and female partners, and 1 reported only female partners. None of the 16 WSW who reported sex exclusively with women reported any injection drug use. Therefore, analyses of risk were limited to those who reported sex with both men and women and those who reported sex exclusively with men (Table 1 ▶). TABLE 1 —Prevalence of Sexual Behaviors, Injection Drug Use, and STD/HIV Infections: Population-Based Survey, Northern California Compared with women who had sex exclusively with men, women who had sex with both men and women were significantly more likely to report past and recent high-risk sexual behavior, including sex with an HIV-positive man, multiple male sexual partners, sex with a man who has sex with men, sex with an injection drug user, trading of sex for drugs or money, and anal sex. They were also more likely to report past and recent injection drug use, including use of heroin, cocaine, and speed. Finally, they were more likely to have serological markers for both hepatitis B virus (anti-HBc, HbsAG, or both) and hepatitis C virus (anti-HCV). Rates of HIV and other STDs did not significantly differ owing to the small numbers of these infections. The rates of sexual and injection drug risk activities exhibited by women in this population-based survey who reported sex with both men and women place this group at potentially higher risk of HIV and other STDs than women who were exclusively sexual with either men or women. Prevention efforts should avoid assumptions based on reported sexual identity and should acknowledge that women who report sex with both women and men may be at increased risk for HIV and other STDs.

Impact of HIV infection on mortality and accuracy of AIDS reporting on death certificates.

To assess the impact of HIV infection on mortality and the accuracy of AIDS reporting on death certificates, we analyzed data from 6704 homosexual and bisexual men in the San Francisco City Clinic cohort. Identification of AIDS cases and deaths in the cohort was determined through multiple sources, including the national AIDS surveillance registry and the National Death Index. Through 1990, 1518 deaths had been reported in the cohort and 1292 death certificates obtained. Of the 1292 death certificates, 1162 were for known AIDS cases, but 9% of the AIDS cases did not have HIV infection or AIDS noted on the death certificate. Only 0.7% of the decedents had AIDS listed as a cause of death and had not been reported to AIDS surveillance. AIDS and HIV infection was the leading cause of death in the cohort, with the highest proportionate mortality ratio (85%) and standardized mortality ratio (153 in 1987), and the largest number of years of potential life lost (32,008 years). The devastating impact of HIV infection on mortality is increasing and will require continued efforts to prevent and treat HIV infection.