Partner-Specific Sexual Behavioral Differences Between Phase 3 HIV Vaccine Efficacy Trial Participants and Controls

Exploring evidence for behavioral risk compensation among participants in an HIV vaccine clinical trial

BACKGROUND

HIV vaccine trial participants may engage in behavioral risk compensation due to a false sense of protection. We conducted an ancillary study of an HIV Vaccine Trials Network (HVTN) vaccine efficacy trial to explore risk compensation among trial participants compared to persons who were willing to participate but ineligible based on previous exposure to the Ad5 virus (Ad5+) across three timepoints.

METHODS

Participants were drawn from the Atlanta, GA site of the HVTN 505 vaccine trial. From 2011-2013, all persons who met prescreening criteria for the clinical trial and presented for Ad5 antibody testing were invited to participate in the ancillary study. Data were collected from vaccine trial participants (n=51) and Ad5+ participants (n=60) via online surveys across three timepoints: baseline, T2 (after trial participants received 2/4 injections) and T3 (after trial participants received 4/4 injections). Data analyses assessed demographic, psychosocial, and behavioral differences at baseline and changes at each timepoint.

RESULTS

At baseline, Ad5+ participants were less likely to have some college education (p=0.024) or health insurance (p=0.008), and were more likely to want to participate in the vaccine trial "to feel safer having unprotected sex" (p=0.005). Among vaccine trial participants, unprotected anal sex with a casual partner (p=0.05), HIV transmission worry (p=0.033), and perceived chance of getting HIV (p=0.027), decreased across timepoints.

CONCLUSIONS

Study findings suggest that persons with previous exposure to Ad5 may be systematically different from their Ad5-negative peers. Unprotected anal sex with a casual partner significantly decreased among HIV vaccine trial participants, as did HIV worry and perceived chance of getting HIV. Findings did not support evidence of risk compensation among HIV vaccine trial participants compared to Ad5+ participants.

Lower HIV prevalence among Asian/Pacific Islander men who have sex with men: a critical review for possible reasons

We conducted a critical literature review for possible reasons that may explain the lower HIV prevalence observed among API MSM compared to MSM of other races/ethnicities. Trends emerging from the literature suggest that traditional individual-level factors-unprotected anal intercourse, substance use, STD prevalence, rates and frequency of HIV testing, and utilization of HIV prevention services-do not appear to be related to the lower HIV prevalence among API MSM. Some evidence suggests that socio-cultural and structural factors might be the more critical forces in determining racial/ethnic disparities of HIV among MSM. For API MSM, these factors include structures of sexual networks, access to and reception of medical care and treatment among HIV-positive MSM, and influences of different levels and types of acculturation. Moreover, emerging risk reduction strategies, such as seroadaptive behaviors, could play a role. Future research should address these factors in intervention design. In addition, better theories of resilience and measurement of strengths and protective factors are needed to enhance the efficacy of HIV interventions.

Egocentric network data provide additional information for characterizing an individual's HIV risk profile

OBJECTIVE

We investigated the hypothesis that partner-specific characteristics are important to improve an individual's risk characterization.

DESIGN

It has been shown that the egocentric network structure is important to establish a person's risk for infection.

METHODS

The study was cross-sectional in its design and enrolled 1231 volunteers at one HIV testing site in Rio de Janeiro, Brazil, and applied an adapted ego-network questionnaire. Each individual was interviewed about their own risk factors and those related to up to 10 sex partners. We used the dyadic data analysis method in which each relationship forms a record. Two receiver operator characteristic curves were generated, and the ability to correctly predict volunteers' HIV serostatus based on a model with characteristics of volunteers and sex partners and another with only volunteers' characteristics was evaluated.

RESULTS

Partner-related variables were associated with HIV serostatus both for men and women. The model with volunteer/sex partners' characteristics performed better in discriminating between HIV-positive and negative volunteers only for men but not for women. The c statistic for men volunteers was 0.82 [95% confidence interval (CI) 0.77-0.87] for the volunteer alone model and 0.88 (95% CI 0.86-0.91) for the combined model (P = 0.03). The values for women were 0.75 (95% CI 0.65-0.86) and 0.78 (95% CI 0.71-0.85), respectively (P = 0.71).

CONCLUSION

Ego-network theory-based approaches provide additional information for characterizing risk for HIV infection among men.

Sources of Human Immunodeficiency Virus and Sexually Transmitted Disease Information and Responses to Prevention Messages among Massachusetts Men Who Have Sex with Men

Purpose.

Sexually transmitted disease (STD) rates have continued to increase among men who have sex with men (MSM). The present study used qualitative methods to assess sources of human immunodeficiency virus (HIV)/STD information and responses to HIV/STD prevention messages among MSM. This was done to understand how to design more effective media campaigns on HIV/STD prevention and testing for this population.

Design.

One-on-one semistructured, qualitative interviews and a brief demographic written survey were conducted.

Setting.

A Massachusetts community-based organization specializing in HIV/AIDS healthcare.

Participants.

A novel, modified, respondent-driven sampling method was used to recruit a diverse sample of 50 Massachusetts MSM between January and April 2005; qualitative interviews were conducted until redundancy in responses was achieved.

Method.

Qualitative data were analyzed using content analysis. NVIVO software was used to organize transcripts, identify themes, and report frequency of responses.

Results.

Respondents reported having derived information on sexual health from multiple media sources. Direct outreach, gay- and HIV-centered organizations, print and broadcast media, public transportation ads, and the Internet held the greatest potential for dissemination. Primary care providers were also frequently seen as trusted sources of HIV/STD prevention information. Ideas for content often included having “people just like you” in ads.

Conclusion.

Health messages that focus on getting tested for HIV and STDs, practicing safe sex, and incorporating straightforward and accurate information on prevention may be the most acceptable to MSM. Providers should be proactive in disseminating information about HIV/STD prevention.

Health care access and sexually transmitted infection screening frequency among at-risk Massachusetts men who have sex with men

OBJECTIVES

We sought to assess risk exposures, health care access, and screening rates for HIV and sexually transmitted infections (STIs) among men who have sex with men (MSM) in Massachusetts.

METHODS

We used a modified respondent-driven sampling method to collect data between March 2006 and May 2007. Overall, 126 MSM completed a survey.

RESULTS

Seventy percent of participants reported unprotected receptive anal intercourse with at least 1 nonmonogamous male partner; 50% reported having had a previous STI. Although 98% had visited a health care provider in the previous year, 39% had not been screened for STIs during the previous 2 years. Bisexual respondents were less likely to have told their health care providers that they engage in male-to-male sexual contact (OR = 4.66; P < .001), less likely to have been tested for STIs during in the previous 2 years (OR = 6.91; P < .001), and more likely to engage in insertive anal intercourse without a condom with an HIV-infected partner (OR = 5.04; P < .005) than were non-bisexual respondents.

CONCLUSIONS

Clinicians need to assess sexual risk-taking behaviors and more routinely screen for STIs among sexually active men regardless of disclosure of a history of having sex with men.

Measuring the public-health impact of candidate HIV vaccines as part of the licensing process

The full impact of vaccines against infectious diseases is manifest at both the individual and the community levels. We argue that evaluating the community-level impact of HIV vaccine candidates should be an integral part of the licensing process. We describe a framework for the public-health evaluation of an HIV vaccine, which is based on the interactive use of mathematical models and community randomised clinical trials (C-RCTs) following completion of individual-based clinical trials (I-RCTs). Mathematical models of HIV vaccine can be used to take public-health considerations into account during the licensing process and can also help to select promising vaccine candidates for testing in C-RCTs. We also describe community and individual-based measures useful for defining public-health criteria necessary to guide the licensing process. To move forward, it is crucial to reach a consensus on what should constitute adequate public-health criteria. At the very least, a suitable vaccine would provide some individual benefit to vaccinees and not be detrimental to the population at large. In future I-RCTs and C-RCTs, quantifying each protective vaccine characteristic (eg, reductions in susceptibility or viral load) is important if regulators are to evaluate adequately the potential community-level impact of the vaccine across different settings, populations, and conditions of use.