Who will enroll? Predicting participation in a phase II AIDS vaccine trial.

BACKGROUND: The problems of underenrollment and selective enrollment may undermine AIDS vaccine trials. If prospective study subjects' stated willingness to participate (WTP) in hypothetical vaccine trials predicts future enrollment, then measuring WTP before recruitment may enhance the enrollment in, and ethics of, such trials. METHODS: We prospectively studied changes over an 18-month period in the stated WTP in, and knowledge of, a hypothetical AIDS vaccine trial among 610 Philadelphia residents at high risk for HIV infection. Of these people, 499 were subsequently recruited to participate in an actual, phase II AIDS vaccine trial. We used multivariable logistic regression and the area under the receiver-operating characteristic (ROC) curve to model predictors of actual enrollment. RESULTS: Actual enrollment rates were 8.3%, 6.8%, 15.8%, and 29.0% among those who had initially said they were "definitely not," "probably not," "probably," and "definitely" willing to participate, respectively (p =.006). The area under the ROC curve was 0.65, indicating a modest ability of stated WTP to differentiate those who enroll from those who do not. Knowledge of basic vaccine trial concepts, though unrelated to enrollment, increased over an 18-month period with repeated education sessions (p <.0001), whereas stated WTP declined over this same period (p <.0001). CONCLUSION: Although other factors not captured by stated WTP may also influence future enrollment, prospectively assessing stated WTP may augment the validity of the informed consent process, help prevent underenrollment, and clarify the population from which the study sample is drawn.     

Race and HIV Clinical Trial Participation

PurposeThis study was designed to examine at the role race/ethnicity plays in human immunodeficiency virus (HIV) clinical trial enrollment.BackgroundHIV clinical trials are vitally important for improving knowledge about medications and their impact on the pathogenesis of HIV/AIDS. African Americans are disproportionately underrepresented in HIV clinical trials.MethodsA 49-item survey was administered to 145 patients at an urban HIV clinic to explore race and HIV clinical trial participation.ResultsStudy participants were 56% Caucasian, 19% other, 16% African American, and 13% Hispanic. Fewer African Americans had been asked to participate in a trial compared to other groups (8% vs 24%) (p < .05). African Americans were less likely to volunteer for a trial compared to Hispanics and Caucasians, but African Americans did not differ significantly in their willingness participate in clinical trials vs other racial groups. In a regression model age, past trial participation, monetary gain, and comfort with the clinical setting predicted willingness to participate in a trial across racial groups (p < .05).DiscussionThere is a strong need to identify strategies to increase African American enrollment in trials. Such strategies need to begin with trial recruiters actively seeking out African Americans for clinical trial enrollment.     

Willingness to volunteer in future preventive HIV vaccine trials: issues and perspectives from three U.S. communities

This study examined perceived risks, benefits, and desired information related to willingness to volunteer in preventive HIV vaccine trials. SAMPLE: Purposive sampling was used to select 90 participants among injecting drug users (Philadelphia, PA, U.S.A.); gay men (San Francisco, CA, U.S.A.); and black Americans (Durham, NC, U.S.A.). METHODS: A qualitative interview guide elicited perceived benefits, risks, and desired information relating to trial participation. Themes were developed from the transcribed texts and from freelists. RESULTS: Stated willingness to volunteer in a preventive HIV vaccine trial was similar across the three communities. Eight perceived benefits were reported, including self-benefits, altruism, and stopping the spread of AIDS. Seven perceived risks were reported, including negative side effects and vaccine safety issues, contracting HIV from the vaccine, and social stigmatization. Participants voiced the desire for eight types of information about issues relating to trust and confidentiality in the research process, health complications and later assistance, and vaccine trial methodology. CONCLUSIONS: In this study, many benefits as well as risks of preventive HIV vaccine trial participation were cited. Scientists conducting preventive HIV vaccine trials need to address community perceptions of risks and provide information about the research if trial enrollment is to be diverse and successful.     

Randomized,controlled evaluation of a prototype informed consent process for HIV vaccine efficacy trials

Procedures must be developed to ensure that valid informed consent is obtained from participants in HIV vaccine efficacy trials. A prototype informed consent process was evaluated among 4,892 persons at high risk for HIV infection in the HIV Network for Prevention Trials Vaccine Preparedness Study (VPS), a prospective cohort study of HIV seroincidence in eight U.S. metropolitan areas. Twenty percent of VPS participants were selected at random to undergo the prototype informed consent process at VPS month 3. Participants' knowledge of 10 key HIV vaccine trial concepts and willingness to participate in HIV vaccine efficacy trials were assessed and compared at baseline and semiannually thereafter for 18 months. Knowledge of HIV vaccine trial concepts was low at baseline. Participation in the prototype process was associated with substantial and sustained increases in knowledge (relative risks for the 10 items, 1.04-2.26), which were of similar magnitude across HIV risk groups, race/ethnicity, and educational levels. It is recommended that the prototype informed consent process be adopted for future HIV vaccine efficacy trials as well as for clinical trials in other research areas.     

Assessing the attitudes, knowledge, and awareness of HIV vaccine research among adults in the United States

OBJECTIVES: To assess HIV vaccine research attitudes, awareness, and knowledge among adults in the general US population, African Americans, Hispanics, and men who have sex with men (MSM). METHODS: Applying results of focus groups and a media content analysis, a survey was designed and conducted to validate key HIV vaccine research themes and messages identified by focus groups and a media content analysis. Between December 2002 and February 2003, 3509 telephone interviews were conducted, including 2008 randomly selected from the general population, and 501 population-specific samples of African Americans and Hispanics, and 500 from MSM. RESULTS: Although the majority of each population believes that an HIV preventive vaccine is the best way to control and end the global AIDS epidemic, only 34.9% of African Americans and 28.8% of the general population are supportive of someone they know volunteering for an HIV vaccine trial. The study also found that 47.1% of African Americans, 26.5% of Hispanics, and 13.4% of MSM believed an HIV vaccine already exists and is being kept secret, and 78.0% of African Americans, 57.5% of Hispanics, and 68.0% of MSM did not know or incorrectly believed that the vaccines being tested could cause HIV infection. A subanalysis of the general population also found that women generally had less knowledge of or a decreased awareness about HIV vaccine research. CONCLUSIONS: Awareness, knowledge, and attitudes toward HIV vaccine research vary by population and these issues must be addressed to ensure an adequate number of volunteers for future domestic HIV preventive vaccine clinical trials. In some populations, barriers such as misinformation and distrust must be targeted to increase support for HIV vaccine research.     

HIV vaccine trial participation among ethnic minority communities: barriers, motivators, and implications for recruitment

BACKGROUND: Underrepresentation of ethnic minority communities limits the generalizability of HIV vaccine trial results. We explored perceived barriers and motivators regarding HIV vaccine trial participation among low-socioeconomic ethnic minority respondents at risk for HIV. METHODS: Six focus group interviews were conducted using a semistructured interview guide. Participants (N = 58, mean age = 36 years, 37% female, and 56% Latino/a and 35% African American) were recruited using venue-based sampling in Los Angeles. Data were analyzed using narrative thematic analysis and Ethnograph qualitative software. RESULTS: Perceived barriers to HIV vaccine trial participation, in rank order, were (1) vaccine-induced HIV infection, (2) physical side effects, (3) uncertainty about vaccine efficacy, (4) uncertainty about other vaccine characteristics, (5) mistrust, (6) low perceived HIV risk, (7) study demands, (8) stigma, and (9) vaccine-induced HIV seropositivity. Motivators were (1) protection against HIV infection, (2) free insurance and/or medical care, (3) altruism, and (4) monetary incentives. CONCLUSIONS: Population-specific HIV vaccine trial recruitment and implementation strategies should address trial risks from a family perspective, cultural gender norms, mistrust, low perceived HIV risk, the importance of African-American and Latino/a community participation in HIV vaccine trials, and misconceptions about gaining protection against HIV infection. Increasing the cultural relevance of trial recruitment and implementation should facilitate the participation of Latinos/as and African Americans in HIV vaccine trials.     

The HVTN protocol 903 vaccine preparedness study: lessons learned in preparation for HIV vaccine efficacy trials

Successful recruitment and retention of HIV-uninfected at-risk participants are essential for HIV vaccine efficacy trials. A multicountry vaccine preparedness study was started in 2003 to assess enrollment and retention of HIV-negative high-risk participants and to assess their willingness to participate in future vaccine efficacy trials. HIV-negative high-risk adults were recruited in the Caribbean, in Southern Africa, and in Latin America, and were followed for 1 year. Participants included men who have sex with men, heterosexual men and women, and female sex workers. History of sexually transmitted infections and sexual risk behaviors were recorded with HIV testing at 0, 6, and 12 months, and willingness to participate in future vaccine trials was recorded at 0 and 12 months. Recruitment, retention, and willingness to participate in future trials were excellent at 3 of the 6 sites, with consistent declines in risk behaviors across cohorts over time. Although not powered to measure seroincidence, HIV seroincidence rates per 100 person-years (95% confidence interval [CI]) were as follows: 2.3 (95% CI: 0.3 to 8.2) in Botswana, 0.5 (95% CI: 0 to 2.9) in the Dominican Republic, and 3.1 (95% CI: 1.1 to 6.8) in Peru. The HIV Vaccine Trials Network 903 study helped to develop clinical trial site capacity, with a focus on recruitment and retention of high-risk women in the Americas, and improved network and site expertise about large-scale HIV vaccine efficacy trials.     

Willingness to participate in HIV vaccine trials among men who have sex with men in Rio de Janeiro, Brazil. Projeto Praça Onze Study Group

Evaluation of HIV vaccines requires high-risk individuals willing to participate in a vaccine trial. We investigated the willingness to participate in HIV vaccine trials of initially HIV-seronegative homosexual men enrolled in an HIV seroincidence cohort study. Of 815 initially HIV-seronegative participants, 569 (69.8%) reported willingness to participate in an HIV vaccine trial. Altruism was the primary reason given for wanting to participate. Fear of HIV infection from the study's immunizations and a vaccine-induced positive HIV test result were the main reasons for not wanting to participate. Of the 34 study subjects who eventually had HIV seroconversion, 29 (85%) had indicated a willingness to participate. In a univariate analysis, factors associated with willingness to participate included HIV seroconversion during follow-up (odds ratio [OR]. 2.6; p =.04), low educational level (OR, 1.6; p =.005), low family income (p =.02), and exchanging sex for housing, food, or clothing (OR 6.1; p =.005). Students were less likely to be willing to participate in a trial (OR, 0.7; p = .03), as well as those who reported sex at the first encounter (OR, 0.7; p = .05). In a multivariate analysis, low education level, infection with Condyloma, and exchanging sex for housing, food, or clothing were positively associated with willingness to participate, whereas being a student and reporting sex at first encounter were negatively associated. In general, factors indicative of high-risk of HIV infection were associated with a higher willingness. These data demonstrate that this high-risk homosexual male cohort has a high willingness to participate in HIV vaccine trials.     

Pregnancy prevention practices among women with multiple partners in an HIV prevention trial

BACKGROUND: Women enrolled in microbicide and pre-exposure prophylaxis (PrEP) HIV prevention trials are not allowed to continue use of study products when pregnant because of fetal safety concerns. High pregnancy rates among women in trials can undermine statistical measures of safety and effectiveness. METHODS: Women enrolled in a PrEP trial in Ghana, Nigeria, and Cameroon had an overall pregnancy rate of 52 per 100 person-years of observation. In-depth interviews were conducted with 67 women who were asked to describe any changes made in their pregnancy prevention practices after enrolling in the trial. RESULTS: Most women (n = 44, 65%) reported changing pregnancy prevention practices after enrolling in the trial. Twice as many reported using condoms for pregnancy prevention after enrollment (n = 56, 84%) than before (n = 27, 40%). Cluster analysis identified site-specific patterns. Nigerian women tended to report using condoms for dual protection before and after trial enrollment. Cameroonian women tended to rely on natural methods before and after trial enrollment. Ghanaian women tended to switch from hormonal methods to condoms. CONCLUSIONS: The role of condoms in HIV prevention trials must not be diminished. Their use-effectiveness for contraception is likely too low for microbicide and PrEP trial needs, however. HIV prevention trials with women should be appropriately staffed to provide effective contraceptive counseling and, if needed, direct provision of contraceptives. This must be done without undermining women's reproductive rights.     

Determinants of Participation in HIV Clinical Trials: The Importance of Patients’ Trust in Their Provider

Abstract

Purpose: To investigate the factors that contribute to willingness to participate in HIV clinical trials and to determine the impact of a brief intervention on willingness to participate. Methods: 115 consecutive outpatients receiving HIV primary care participated in this prospective study. Each patient completed a questionnaire about clinical trials and met with a research assistant who discussed the purpose of clinical trials. After the educational intervention, participants completed a second questionnaire and responses from the two surveys were compared. Results: 115 patients were enrolled (56% had previously enrolled in a clinical trial; 50% of whom were currently enrolled in a trial); 92% would consider participating in a future clinical trial. Increased patient trust in the provider was associated with increased willingness to participate in a trial. After the intervention, 94% indicated that they would be willing to be contacted about a clinical trial for which they may be eligible and 85% preferred to be contacted by their primary physician. Conclusions: Patients’ trust in their provider may predict willingness to participate in clinical trial. Providing HIV-infected patients and their providers with information about HIV clinical trials at the site where they receive care may increase participation rates in HIV clinical trials.     

Design, implementation, and evaluation at entry of a prospective cohort study of homosexual and bisexual HIV-1-negative men in Belo Horizonte, Brazil: Project Horizonte

BACKGROUND AND OBJECTIVES: Project Horizonte, an open cohort of homosexual and bisexual HIV-1-negative men, is a component of the Minas Gerais AIDS Vaccine Program of the Federal University of Minas Gerais, Belo Horizonte, Brazil. Its objectives included the evaluation of seroincidence of HIV, to ascertain the role of counseling on behavior modification and to assess their willingness to participate in future HIV vaccine trials. METHODS: Various means of recruitment were used, including pamphlets, notices in community newspapers, radio, and television, at anonymous testing centers, and by word of mouth. RESULTS: From October 1994 to May 1999, 470 volunteers were enrolled. Their mean age was 26 years and over 70% of them had high school or college education. During the follow-up, they were seen every 6 months, when they received counseling and condoms, and when HIV testing was done. Eighteen seroconversions were observed, and the incidence rates estimates were 1.75 per 100 and 1.99 per 100 person-years, for 36 and 48 months of follow-up, respectively. During the entire period, 139 volunteers were lost to follow-up. Among them, 59 (42.4%) never returned after the initial visit and 51 (36.7) came only once after their initial visit. No losses were observed for those observed during follow-up for more than 3 years. At enrollment, 50% of participants said they would participate in a vaccine trial, and 30% said they might participate. CONCLUSIONS: The results obtained up to this moment confirm the feasibility of following this type of cohort for an extended period, estimating HIV incidence rate, and evaluating counseling for safe sexual practices in preparation for clinical trials with candidate HIV vaccines in Brazil.     

Who Enrolls in an Online Cancer Survivorship Program? Reach of the INSPIRE Randomized Controlled Trial for Hematopoietic Cell Transplantation Survivors

The internet can be a valuable tool in delivering survivorship care to hematopoietic cell transplantation (HCT) cancer survivors. We describe the reach of INSPIRE, an Internet and social media-based randomized controlled trial, to address healthcare and psychosocial needs of HCT survivors. All survivors 2-10 years after HCT for hematologic malignancy or myelodysplasia from 6 transplantation centers in the US were approached by mail and follow-up calls. Eligible participants had access to the Internet, an email address, and did not have active disease in the past 2 years. We used logistic regression to determine characteristics of eligible survivors who were more or less likely to enroll. Of 2578 eligible HCT survivors, 1065 (41%) enrolled in the study. The mean age of enrollees was 56.3 ± 12.6 years (range, 19 to 89 years), 52% were male, and 94% were white. Survivors less likely to enroll included those who were male, age <40 years, and who received an autologous transplant (all P < .001). Compared with white survivors, African Americans were less likely to enroll (P < .001), whereas Native Americans/Alaska Natives were more likely to join the study (P = .03). The reach of the INSPIRE program was broad, including to survivors who traditionally have less access to resources, such as Native Americans/Alaskan Natives and rural residents. Strategies are still needed to improve the enrollment of online studies of survivorship resources for males, young adults, African American, and autologous HCT survivors because their use may improve outcomes.     

Willingness of injection drug users to participate in an HIV vaccine efficacy trial in Bangkok, Thailand.

We assessed willingness to participate in an HIV recombinant gp120 bivalent subtypes B/E candidate vaccine efficacy trial among 193 injection drug users (IDUs) attending drug treatment clinics in Bangkok, Thailand. IDUs previously enrolled in a prospective cohort study were invited to group sessions describing a potential trial, then completed questionnaires assessing comprehension and willingness to participate. A week later, they completed a follow-up questionnaire that again assessed comprehension and willingness to participate, as well as barriers to and positive motives for participation, with whom (if anyone) they talked about the information, and whether others thought participation was a good, bad, or neutral idea. At baseline, 51% were definitely willing to participate, and at follow-up 54%; only 3% were not willing to participate at either time. Comprehension was high at baseline and improved at follow-up. Participants who viewed altruism, regular HIV tests, and family support for participation as important were more willing to volunteer. Frequency of incarceration and concerns about the length of the trial, possible vaccine-induced accelerated disease progression, and lack of family support were negatively associated with willingness. Overall, IDUs comprehended the information needed to make a fully informed decision about participating in an rgp120 vaccine efficacy trial and expressed a high level of willingness to participate in such a trial.     

Demographic and behavioral contextual risk groups among men who have sex with men participating in a phase 3 HIV vaccine efficacy trial: implications for HIV prevention and behavioral/biomedical intervention trials

Recent outbreaks of syphilis and gonorrhea coupled with reported increases in HIV-risk behavior among men who have sex with men (MSM) have raised concerns about a potential resurgence of HIV among MSM. These concerns have led some to suggest the need for a paradigm shift in how HIV-prevention programs are designed and implemented. In this analysis, baseline demographic, sexual partnership, and substance use information was used to identify contextual-risk groups among 5,095 HIV-seronegative MSM enrolled in a 36-month phase 3 HIV vaccine efficacy trial across 61 sites primarily in North America. Eight demographic and behavioral contextual risk groups were identified, with annualized HIV seroincidence ranging from 1.8% to 6.3% across groups. Men in primary HIV-serodiscordant relationships had the lowest HIV seroincidence (1.8%), while an older group of men with many sex partners had the highest (6.3%). Visit-schedule compliance and study retention were lowest among younger non-White men and highest among older popper users, with annualized HIV seroincidence of 2.9% and 3.5%, respectively. Differences in HIV incidence, study compliance, and retention observed among contextual-risk groups suggest that responsiveness to heterogeneity within risk group (eg, MSM) could benefit screening, enrollment, and retention of HIV-prevention programs and intervention trials, reducing the time and cost related to their design, implementation, and conclusion.     

Participant retention in clinical trials of candidate HIV vaccines

OBJECTIVE:: To determine predictors of loss to follow-up (LTFU) in trials of candidate HIV vaccines. METHODS:: Data were obtained from trials of candidate preventive HIV vaccines conducted by the AIDS Vaccine Evaluation Group (AVEG) and HIV Network for Prevention Trials (HIVNET) that enrolled HIV-negative volunteers. Analytic models included multiple logistic regression and generalized estimating equations. RESULTS:: Of 3033 volunteers enrolled in 48 trials, 282 (9.3%) persons did not complete follow-up. In univariate analyses, age, trial duration, and number of immunizations were associated with LTFU. In a multivariate logistic model, age (per year) (adjusted odds ratio [AOR] = 0.96, 95% confidence interval [CI]: 0.95, 0.98) and study duration (per month) (AOR = 1.04, 95% CI: 1.01, 1.08) remained significantly associated with LTFU. CONCLUSIONS:: Younger age and increasing trial duration predicted LTFU. Limiting enrollment in trials of novel products to those less than 40 years of age may exclude participants shown to have improved retention. Trials should be designed to last only as long as required to address the scientific question. Retention efforts in future trials should especially address younger persons.     

Incident HIV infection in a high-risk, homosexual, male cohort in Rio de Janeiro, Brazil.

An HIV seroincidence study was conducted to identify a high-risk population for HIV prevention trials. Inclusion criteria were male gender, homosexual behavior, age between 18 and 50 years, and negative HIV serostatus; 862 study subjects were screened and 753 were enrolled and observed during follow-up for a mean of 1.5 years. In this population, 34 people had HIV seroconversions for an overall annual seroincidence of 3.1% (95% confidence interval [CI], 2.1%-4.1%). Among study subjects <20 years old, annual incidence was 8.4% (95% CI, 1.7%-15%). Independent risk factors for seroconversion were age <25 years (p = .01), hepatitis B core antibody seropositivity (p > .01), sex at first encounter in the preceding 6 months (p = .11), and a history of gonorrhea or condyloma in the 6 months before seroconversion (p = .04 and p = .08, respectively). At enrollment, 85% of the eventual seroconverters said they would participate in a vaccine trial; all agreed to participate when told there would be a placebo arm. Follow-up rates were 97%, 91%, and 88% at 6, 12, and 18 months, respectively. The HIV-1 subtype was B for each of the first 17 seroconverters. These data demonstrate the suitability of this cohort for HIV prevention trials, based on high HIV incidence and retention rates, and a willingness to participate in such trials.     

Motivations for participating in an HIV vaccine efficacy trial

Understanding why people join HIV vaccine efficacy trials is critical for trial recruitment and education efforts. We assessed participants' motivations for joining the VaxGen VAX004 study, a randomized, double-blind, placebo-controlled, phase 3 multicenter trial. Of 5417 participants, 94% were men who have sex with men (MSM) and 6% were women at risk for heterosexual transmission of HIV. Most participants gave altruistic reasons for trial participation: 99% reported having joined to help find an HIV vaccine, and 98% reported having joined to help their community. Some gave more personal reasons: 56% joined to reduce risk behavior and 46% joined to get protection from HIV. Additional reasons related to receiving services or compensation included to obtain information about HIV (75%), to receive free HIV testing (34%), and for financial reimbursement (14%). Multivariate logistic regression analysis showed that female participants were significantly more motivated than male participants to join the trial for protection and to receive services or compensation (all P<0.05). Participants with 13 or more sex partners in the 6 months before enrollment were more likely than those with fewer sex partners to report having joined the trial for protection but less likely to have joined to reduce risk behavior (both P<0.05). Because many participants reported personal protection from HIV as their reason for joining, vaccine trial risk-reduction counseling should continue to emphasize the placebo-controlled trial design and unknown efficacy of the test product, particularly for women and persons with large numbers of sex partners. Because a significant minority of participants reported joining to receive HIV information, HIV testing, and financial reimbursement, a need is indicated for provision of HIV prevention services outside research trials and for monitoring to ensure that participants are not motivated to join trials for financial gain.     

Factors affecting African-American participation in AIDS research

BACKGROUND: Although African Americans are disproportionately affected by the AIDS epidemic, they are underrepresented in AIDS research, particularly in AIDS clinical trials. This study examines a multidimensional construct of distrust and other factors that may affect willingness to participate in AIDS research. METHODS: A total of 301 African Americans (aged >/=18 years) in Durham, North Carolina participated in a cross-sectional survey. In-person interviews, 20 to 25 minutes in length, were conducted with participants. Structural equation modeling was used to develop models exploring distrust and other factors affecting willingness to participate in AIDS research among African Americans. RESULTS: Distrust was the strongest inverse predictor of willingness to participate in AIDS clinical trials. Distrust was not significantly associated with willingness to participate in AIDS surveys and educational interventions. Altruism, facilitators/barriers, religiosity, and economic group membership were also significantly associated with willingness to participate in AIDS clinical trials. Only altruism was significantly associated with willingness to participate in AIDS surveys and educational interventions. CONCLUSIONS: Distrust about research institutions is a significant barrier to recruiting African Americans in AIDS clinical trials. Issues of distrust need to be acknowledged by researchers to develop better recruitment and retention strategies when conducting AIDS clinical trials in African-American communities.     

Recruitment and baseline epidemiologic profile of participants in the first phase 3 HIV vaccine efficacy trial

OBJECTIVE: To describe recruitment and baseline epidemiologic characteristics of volunteers in the first phase 3 placebo-controlled trial of a recombinant gp120 HIV vaccine (AIDSVAX B/B). METHODS: Volunteers were gay/bisexual men or women at risk for sexually transmitted HIV infection. Recruitment strategies, demographics, and risk factors were assessed. HIV status was determined by standard HIV-1 antibody assays. Seronegative/viremic HIV infection at enrollment was determined using the HIV-1 nucleic acid test. RESULTS: From June 1998 through October 1999, 5417 of 7185 volunteers screened were enrolled at 61 sites in the United States, Canada, and The Netherlands. Successful recruitment methods included distribution of study information at gay venues, advertising and media coverage, and referrals from volunteers. Most volunteers were altruistically motivated, men (98%), young (median, 36 years), white (83%), well educated (61% college education or more), and at high risk for HIV during the 6 months before enrollment. At baseline, 14 were HIV infected (12 were seronegative but viremic; 2 were seropositive and viremic). CONCLUSION: Men and women at high risk for sexually transmitted HIV infection were successfully recruited for the first phase 3 HIV vaccine efficacy trial. Knowledge of recruitment and baseline epidemiologic characteristics of participants in this trial will provide valuable guidance for designing and conducting future trials.