The epidemiological contribution to the preparation of field trials for HIV and STI vaccines: objectives and methods of feasibility studies

Assessing the feasibility of hepatitis C virus vaccine trials: results from the Hepatitis C Incidence and Transmission Study-community (HITS-c) vaccine preparedness study

Efficacy trials of preventive hepatitis C virus (HCV) vaccine candidates raise challenging scientific and ethical issues. Based on data from the first 3 years of a community-based prospective observational study - the Hepatitis C Incidence and Transmission Study-community (HITS-c) - this paper examines the feasibility of conducting trials of candidate HCV vaccines with people who inject drugs (PWID) in Sydney, Australia. Of the 166 PWID confirmed HCV antibody negative and eligible for enrolment, 156 (94%) completed baseline procedures. Retention was high, with 89% of participants retained at 48 weeks and 76% of participants completing at least 75% of study visits within 2 weeks of schedule. The rate of primary HCV infection was 7.9/100 py (95% CI 4.9, 12.7). Of the 17 incident cases, 16 completed at least one follow-up assessment and 12 (75%) had evidence of chronic viraemia with progression to chronic HCV infection estimated to be 6/100 py. Power calculations suggest a chronic HCV infection rate of at least 12/100 py (primary HCV infection rate 16/100 py) will be required for stand-alone trials of highly efficacious candidates designed to prevent chronic infection. However, elevated primary HCV infection was observed among participants not receiving opioid substitution therapy who reported heroin as the main drug injected (26.9/100 py, 95% CI 14.5, 50.0) and those who reported unstable housing (23.5/100 py, 95% CI 7.6, 72.8), daily or more frequent injecting (22.7/100 py, 95% CI 12.2, 42.2) and receptive syringe sharing (23.6/100 py, 95% CI 9.8, 56.7) in the 6 months prior to baseline. These data suggest that it is possible to recruit and retain at-risk PWID who adhere to study protocols and that modification of eligibility criteria may identify populations with sufficiently high HCV incidence. Results support the feasibility of large multi-centre HCV vaccine trials, including in the Australian setting.

Increased hepatitis C virus vaccine clinical trial literacy following a brief intervention among people who inject drugs

INTRODUCTION AND AIMS

While people who inject drugs are at high risk of hepatitis C virus (HCV) infection and will be the target population for future HCV vaccine trials, little is known about clinical trial literacy (CTL) in this group. We assessed the impact of a brief intervention (BI) designed to improve HCV vaccine CTL among people who inject drugs in Sydney, Australia.

DESIGN AND METHODS

People who inject drugs enrolled in a community-based prospective observational study between November 2008 and September 2010 (n = 102) completed a CTL assessment followed immediately by the BI. Post-test assessment was conducted at 24 weeks.

RESULTS

The median age of the sample was 27 years, 73% were male and 60% had 10 or less years of schooling. The median time since first injection was 5 years and 20% reported daily or more frequent injecting. The mean number of correct responses increased from 5.3 to 6.3/10 (t = -4.2; 101df, P < 0.001) 24 weeks post-intervention. Statistically significant differences were observed for three knowledge items with higher proportions of participants correctly answering questions related to randomisation (P = 0.002), blinding (P = 0.005) and vaccine-induced seropositivity (P = 0.003) post-intervention.

DISCUSSION AND CONCLUSIONS

A significant increase in HCV vaccine CTL was observed, suggesting that new and relatively novel concepts can be learned and recalled in this group. These findings support the feasibility of future trials among this population. [Correction added on 21 November 2012, after first online publication: T-score for mean number of correct responses was corrected to '-4.2' in the Results section.]

Risk Factor Detection as a Metric of STARHS Performance for HIV Incidence Surveillance Among Female Sex Workers in Kigali, Rwanda

Background:

The epidemiologic utility of STARHS hinges not only on producing accurate estimates of HIV incidence, but also on identifying risk factors for recent HIV infection.

Methods:

As part of an HIV seroincidence study, 800 Rwandan female sex workers (FSW) were HIV tested, with those testing positive further tested by BED-CEIA (BED) and AxSYM Avidity Index (Ax-AI) assays. A sample of HIV-negative (N=397) FSW were followed prospectively for HIV seroconversion. We compared estimates of risk factors for: 1) prevalent HIV infection; 2) recently acquired HIV infection (RI) based on three different STARHS classifications (BED alone, Ax-AI alone, BED/Ax-AI combined); and 3) prospectively observed seroconversion.

Results:

There was mixed agreement in risk factors between methods. HSV-2 coinfection and recent STI treatment were associated with both prevalent HIV infection and all three measures of recent infection. A number of risk factors were associated only with prevalent infection, including widowhood, history of forced sex, regular alcohol consumption, prior imprisonment, and current breastfeeding. Number of sex partners in the last 3 months was associated with recent infection based on BED/Ax-AI combined, but not other STARHS-based recent infection outcomes or prevalent infection. Risk factor estimates for prospectively observed seroconversion differed in magnitude and direction from those for recent infection via STARHS.

Conclusions:

Differences in risk factor estimates by each method could reflect true differences in risk factors between the prevalent, recently, or newly infected populations, the effect of study interventions (among those followed prospectively), or assay misclassification. Similar investigations in other populations/settings are needed to further establish the epidemiologic utility of STARHS for identifying risk factors, in addition to incidence rate estimation.

Motivators and barriers influencing willingness to participate in candidate HCV vaccine trials: perspectives of people who inject drugs

BACKGROUND

A safe and efficacious vaccine may be the most efficient and cost-effective strategy for controlling the hepatitis C virus (HCV) epidemic among people who inject drugs (PWID) and several candidates are in development. However, little is known about the factors that influence willingness to participate (WTP) in candidate HCV vaccine trials among this group.

METHODS

HCV seronegative PWID recruited between 2008 and 2010 as part of a prospective observational cohort study in Sydney, Australia were asked whether they would be willing to participate in a future candidate hepatitis C vaccine trial and to provide reasons to explain their decision.

RESULTS

Of 113 participants, 74% indicated WTP, 15% were unwilling to participate and 11% reported WTP that was contingent on vaccine characteristics and trial design issues. The most commonly reported motivator for hypothetical trial participation was altruism, followed by potential health benefits, financial remuneration, and knowledge gain. Barriers to hypothetical participation included fears about possible harms to health, such as concerns about vaccine safety, side effects, and acquiring HCV from the vaccine; other barriers included mistrust of biomedical research and time constraints.

CONCLUSIONS

These results may be useful in designing strategies to enhance HCV vaccine trial recruitment and retention and have ethical implications for developing informed consent processes and standards of care.

How informed is consent in vulnerable populations? Experience using a continuous consent process during the MDP301 vaginal microbicide trial in Mwanza, Tanzania

BACKGROUND

HIV prevention trials conducted among disadvantaged vulnerable at-risk populations in developing countries present unique ethical dilemmas. A key concern in bioethics is the validity of informed consent for trial participation obtained from research subjects in such settings. The purpose of this study was to investigate the effectiveness of a continuous informed consent process adopted during the MDP301 phase III vaginal microbicide trial in Mwanza, Tanzania.

METHODS

A total of 1146 women at increased risk of HIV acquisition working as alcohol and food vendors or in bars, restaurants, hotels and guesthouses have been recruited into the MDP301 phase III efficacy and safety trial in Mwanza. During preparations for the trial, participatory community research methods were used to develop a locally-appropriate pictorial flipchart in order to convey key messages about the trial to potential participants. Pre-recorded audio tapes were also developed to facilitate understanding and compliance with gel-use instructions. A comprehension checklist is administered by clinical staff to all participants at screening, enrolment, 12, 24, 40 and 50 week follow-up visits during the trial. To investigate women's perceptions and experiences of the trial, including how well participants internalize and retain key messages provided through a continuous informed consent process, a random sub-sample of 102 women were invited to participate in in-depth interviews (IDIs) conducted immediately after their 4, 24 and 52 week follow-up visits.

RESULTS

99 women completed interviews at 4-weeks, 83 at 24-weeks, and 74 at 52 weeks (a total of 256 interviews). In all interviews there was evidence of good comprehension and retention of key trial messages including that the gel is not currently know to be effective against HIV; that this is the key reason for conducting the trial; and that women should stop using gel in the event of pregnancy.

CONCLUSIONS

Providing information to trial participants in a focussed, locally-appropriate manner, using methods developed in consultation with the community, and within a continuous informed-consent framework resulted in high levels of comprehension and message retention in this setting. This approach may represent a model for researchers conducting HIV prevention trials among other vulnerable populations in resource-poor settings.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN64716212.

Engaging community businesses in human immunodeficiency virus prevention: a feasibility study

PURPOSE

To explore the feasibility of engaging community businesses in human immunodeficiency virus (HIV) prevention.

DESIGN

Randomly selected business owners/managers were asked to display discreetly wrapped condoms and brochures, both of which were provided free-of-charge for 3 months. Assessments were conducted at baseline, mid-program, and post-program. Customer feedback was obtained through an online survey.

SETTING

Participants were selected from a San Diego, California neighborhood with a high rate of acquired immune deficiency syndrome.

PARTICIPANTS

Fifty-one business owners/managers who represented 10 retail categories, and 52 customers.

MEASURES

Participation rates, descriptive characteristics, number of condoms and brochures distributed, customer feedback, business owners'/managers' program satisfaction, and business owners'/managers' willingness to provide future support for HIV prevention were measured.

ANALYSIS

Kruskal-Wallis, Mann-Whitney U, Fisher's exact, and McNemar's tests were used to analyze data.

RESULTS

The 20 business owners/managers (39%) who agreed to distribute condoms and brochures reported fewer years in business and more employees than those who agreed only to distribute brochures (20%) or who refused to participate (41%; p < .05). Bars were the easiest of ten retail categories to recruit. Businesses with more employees and customers distributed more condoms and brochures (p < .05). More than 90% of customers supported distributing condoms and brochures in businesses, and 96% of business owners/managers described their program experience as positive.

CONCLUSION

Businesses are willing to distribute condoms and brochures to prevent HIV. Policies to increase business participation in HIV prevention should be developed and tested.

Are women who work in bars, guesthouses and similar facilities a suitable study population for vaginal microbicide trials in Africa?

BACKGROUND

A feasibility study was conducted to investigate whether an occupational at-risk cohort of women in Mwanza, Tanzania are a suitable study population for future phase III vaginal microbicide trials.

METHODOLOGY/PRINCIPAL FINDINGS

1573 women aged 16-54 y working in traditional and modern bars, restaurants, hotels, guesthouses or as local food-handlers were enrolled at community-based reproductive health clinics, provided specimens for HIV/STI and pregnancy testing, and asked to attend three-monthly clinical follow-up visits for 12-months. HIV positive and negative women were eligible to enter the feasibility study and to receive free reproductive health services at any time. HIV prevalence at baseline was 26.5% (417/1573). HIV incidence among 1156 sero-negative women attending at baseline was 2.9/100PYs. Among 1020 HIV sero-negative, non-pregnant women, HIV incidence was 2.0/100PYs, HSV-2 incidence 12.7/100PYs and pregnancy rate 17.8/100PYs. Retention at three-months was 76.3% (778/1020). Among 771 HIV sero-negative, non-pregnant women attending at three-months, subsequent follow-up at 6, 9 and 12-months was 83.7%, 79.6%, and 72.1% respectively. Older women, those who had not moved home or changed their place of work in the last year, and women working in traditional bars or as local food handlers had the highest re-attendance.

CONCLUSIONS/SIGNIFICANCE

Women working in food outlets and recreational facilities in Tanzania and other parts of Africa may be a suitable study population for microbicide and other HIV prevention trials. Effective locally-appropriate strategies to address high pregnancy rates and early losses to follow-up are essential to minimise risk to clinical trials in these settings.

Microbicides development programme: engaging the community in the standard of care debate in a vaginal microbicide trial in Mwanza, Tanzania

BACKGROUND

HIV prevention research in resource-limited countries is associated with a variety of ethical dilemmas. Key amongst these is the question of what constitutes an appropriate standard of health care (SoC) for participants in HIV prevention trials. This paper describes a community-focused approach to develop a locally-appropriate SoC in the context of a phase III vaginal microbicide trial in Mwanza City, northwest Tanzania.

METHODS

A mobile community-based sexual and reproductive health service for women working as informal food vendors or in traditional and modern bars, restaurants, hotels and guesthouses has been established in 10 city wards. Wards were divided into geographical clusters and community representatives elected at cluster and ward level. A city-level Community Advisory Committee (CAC) with representatives from each ward has been established. Workshops and community meetings at ward and city-level have explored project-related concerns using tools adapted from participatory learning and action techniques e.g. chapati diagrams, pair-wise ranking. Secondary stakeholders representing local public-sector and non-governmental health and social care providers have formed a trial Stakeholders' Advisory Group (SAG), which includes two CAC representatives.

RESULTS

Key recommendations from participatory community workshops, CAC and SAG meetings conducted in the first year of the trial relate to the quality and range of clinic services provided at study clinics as well as broader standard of care issues. Recommendations have included streamlining clinic services to reduce waiting times, expanding services to include the children and spouses of participants and providing care for common local conditions such as malaria. Participants, community representatives and stakeholders felt there was an ethical obligation to ensure effective access to antiretroviral drugs and to provide supportive community-based care for women identified as HIV positive during the trial. This obligation includes ensuring sustainable, post-trial access to these services. Post-trial access to an effective vaginal microbicide was also felt to be a moral imperative.

CONCLUSION

Participatory methodologies enabled effective partnerships between researchers, participant representatives and community stakeholders to be developed and facilitated local dialogue and consensus on what constitutes a locally-appropriate standard of care in the context of a vaginal microbicide trial in this setting.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN64716212.

Using ethnographic fieldwork to inform hepatitis C vaccine preparedness studies with people who inject drugs

BACKGROUND

Feasibility studies are an important component of preparations for field trials of biomedical prevention interventions, including vaccines.

METHODS

We conducted ethnographic fieldwork to assess feasibility, including eligibility and willingness to participate, prior to recruitment of a prospective observational study of hepatitis C negative people who inject drugs (PWID) in Sydney, Australia. Five staff conducted ethnographic fieldwork in 16 locations during 2008. Observations and interactions with PWID were recorded as field notes and data were used iteratively to guide targeting of locations and the follow-up of networks and individuals.

RESULTS

Findings informed the development of the study protocol, resulting in changes in the amount and type of participant reimbursement and the quantity of blood collected at screening, as well as highlighting the need for increased emphasis on communicating eligibility and exclusion criteria and study remuneration procedures.

CONCLUSION

Results illustrate the value of ethnographic research in facilitating consultation and discussion with potential participants in natural settings, identifying motivations and concerns prior to study commencement and providing affected community input into the development of research protocols.

A model for community representation and participation in HIV prevention trials among women who engage in transactional sex in Africa

Actively engaging communities in effective partnerships for the design and implementation of HIV prevention research is vital to the successful conduct of ethically robust, locally-appropriate clinical trials in developing countries. This is especially true in vulnerable at-risk sub-populations, where definitions of "community", "participation" and "representation" can be difficult to apply. This study was conducted to investigate the feasibility of a participatory model of community liaison among an occupational cohort of women at high-risk of HIV and sexually-transmitted infections in Mwanza City, northwest Tanzania in preparation for a Phase III vaginal microbicide trial. This approach was rooted in participatory action-orientated research and used tools adapted from participatory learning and action techniques. During the feasibility study, a mobile community-based sexual and reproductive health service for women working as informal food vendors or in traditional and modern bars, restaurants, hotels and guesthouses was established in 10 city wards. Participatory mapping was carried out by project fieldworkers and wards divided into 78 geographical clusters of facilities in consultation with community members and study participants. Representatives at cluster and ward level were elected in a process facilitated by the site Community Liaison Officer and a site-level Community Advisory Committee established. A logical framework was used to guide the implementation, monitoring and evaluation of the community liaison system (CLS) within the broader feasibility study. The CLS was essential to the successful conduct of the feasibility study and has now been consolidated and expanded as part of the on-going MDP301 Phase III microbicide trial in Mwanza. The participatory model presented in this paper is likely to be generalisable to other vulnerable, stigmatised, at-risk study populations in resource-limited settings.

High prevalence of HIV infection among rural tea plantation residents in Kericho, Kenya

Human immunodeficiency virus type 1 (HIV-1) epidemiology among residents of a rural agricultural plantation in Kericho, Kenya was studied. HIV-1 prevalence was 14.3%, and was higher among women (19.1%) than men (11.3%). Risk factors associated with HIV-1 for men were age (>or=25 years), marital history (one or more marriages), age difference from current spouse (>or=5 years), Luo ethnicity, sexually transmitted infection (STI) symptoms in the past 6 months, circumcision (protective), and sexual activity (>or=7 years). Among women, risk factors associated with HIV-1 were age (25-29 years, >or=35 years), marital history (one or more marriages), age difference from current spouse (>or=10 years), Luo ethnicity, STI symptoms in the past 6 months, and a STI history in the past 5 years. Most participants (96%) expressed a willingness to participate in a future HIV vaccine study. These findings will facilitate targeted intervention and prevention measures for HIV-1 infection in Kericho.

Buenos Aires cohort of men who have sex with men: prevalence, incidence, risk factors, and molecular genotyping of HIV type 1

The prevalence, incidence, risk factors, and molecular genotyping of HIV-1 infection among men who have sex with men (MSM) were assessed through a prospective cohort study. The study was conducted in Buenos Aires from February 2003 to December 2004. Sociodemographic, sexual risk behavior data, and blood samples for HIV testing were collected at baseline and at 6 and 12 months. Cox regression analysis was applied to determine risk factors associated with HIV seroconversion. HIV-positive samples were analyzed by partial (pro/RT) and full-length genome sequencing. Of 811 HIV-negative participants evaluated at baseline, 327 volunteers that fulfilled the inclusion criteria were enrolled. Retention rates at 6 and 12 months were 97.2% and 91.5%, respectively. Twelve MSM seroconverted for HIV infection [incidence rate = 3.9 (95% CI = 2.0-6.7) per 100 person-years]. HIV seroconversion was associated with a greater number of different sexual contacts in the preceding 6 months (> or =10, hazard ratio = 3.3, 95% CI: 1.1-10.4). By partial pro/RT genotyping analysis, 83% HIV-positive samples were subtype B and 17% samples were BF recombinants, most of these being unique recombinant forms. This study describes for the first time the recruitment and follow-up of a cohort of MSM in Argentina. Retention rates and HIV incidence rate were high. These data should be considered as a promising potential population for HIV vaccine trials.

Microbicides development program, Tanzania-baseline characteristics of an occupational cohort and reattendance at 3 months

OBJECTIVES

To determine baseline characteristics of an occupational cohort of women in Mwanza City, Tanzania, and factors associated with reattendance at 3 months, in preparation for a microbicide trial.

STUDY DESIGN

One thousand five hundred seventy-three women aged 16-54 years working in food outlets and recreational facilities were enrolled, interviewed, and examined at community-based reproductive health clinics, provided specimens for HIV/STI and pregnancy testing, and attended 3 monthly clinical follow-up.

RESULTS

Baseline prevalence of HIV was 25.5%; pregnancy 9.7%; herpes simplex virus type-2 74.6%; active syphilis 10.2%, bacterial vaginosis 52.6%; gonorrhea 5.5%; chlamydia 5.9%; and trichomoniasis 12.3%. Reattendance at 3 months was 74.1% and was higher in older women, less mobile women, and in those who received an HIV-negative result at enrollment.

CONCLUSIONS

Baseline characteristics of this occupational group suggest their suitability for microbicide trials. A screening round, locally appropriate informed consent procedures, and effective community tracing may help reduce losses to follow-up in such settings.

Higher HIV-1 incidence and genetic complexity along main roads in Rakai District, Uganda

OBJECTIVE

To determine the association between the incidence of HIV-1 infection and the genetic complexity of HIV-1 strains in 2 geographic strata within Rakai District, Uganda.

METHODS

Study volunteers with recent HIV-1 infections during the period 1997 through 2003 were recruited from 10 communities that were geographically stratified as a main road trading center (n = 5) or a secondary road trading village (n = 5). Cryopreserved plasma was available from 384 volunteers and was the source of viral RNA for genotyping by the multiregion hybridization assay. Hazard ratios (HRs) for a single HIV subtype, a recombinant form, or dual infection for gender and geographic strata were obtained using Cox proportional hazards analysis.

RESULTS

The HIV-1 incidence rate during the period 1999 through 2002 was 1.3 per 100 person-years (PYs) in the trading centers and 1.1 per 100 PYs in the trading villages. The HR for infection with an HIV-1 recombinant strain in trading centers relative to trading villages was 2.3 (95% confidence interval [CI]: 1.0 to 6.7). Among those who changed residence between village strata, the HR for a recombinant HIV-1 infection was 8.1 (95% CI: 0.4 to 47.7).

CONCLUSIONS

HIV-1 incidence and genetic complexity are associated with geographic strata and population mobility in Rakai District and are important variables to be considered in planning and recruitment for vaccine trials.

Using hepatitis A and B vaccination as a paradigm for effective HIV vaccine delivery

Background: An understanding of vaccine acceptance and uptake is imperative for successful vaccination of populations that will be primary targets for vaccination after a vaccine against HIV is developed and ready for dissemination. Experiences with vaccination against vaccine-preventable hepatitis (VPH) among men who have sex with men (MSM) may offer key insights to inform future HIV vaccination strategies. The purpose of this analysis was to explore what is known currently about vaccination among MSM, using knowledge gained from vaccination against VPH, and to identify important considerations from these experiences that must be explored further as a vaccine against HIV is promoted among MSM. Because cultural and political differences make it difficult to extrapolate findings from studies in one country to another, we have focused our analyses on studies conducted in the USA. Methods: Through a qualitative systematic review of published reports, we identified eight studies that reported correlates of VPH among MSM in the USA. Results: Six major domains of variables associated with vaccination against VPH were identified, including: demographics (e.g. younger age, higher educational attainment); increased vaccine knowledge; increased access to health care; provider recommendation; behaviours (e.g. same-sex behaviour, health-promoting and disease-preventing behaviours); and psychosocial factors (e.g. openness about one’s sexual orientation, reduced barriers to being vaccinated, self-efficacy). Conclusions: Further research is needed to understand vaccination behaviour among MSM and to maximise acceptance and uptake after a vaccine exists. Experiences with VPH provide a real-world model on which to base preliminary assumptions about acceptance and uptake of a vaccine against HIV.

Epidemiology of HIV-1 Infection in Agricultural Plantation Residents in Kericho, Kenya

A cross-sectional study was performed to determine the prevalence and risk factors for HIV-1 infection among agricultural plantation residents in Kericho, Kenya. Volunteers were recruited, interviewed, and phlebotomized for HIV-1 serologic testing. Sex-specific adjusted odds ratios were estimated using logistic regression. The overall HIV-1 prevalence was 9.9% (81/820), with prevalence in women more than twice that in men (17.4% vs 8.0%, P=0.001). Among men, elevated HIV-1 prevalence was seen with increasing age, peaking in those older than 30 years (10.3%), marriage (10.4%), Luo tribe affiliation (23.5%), employment (8.9%), travel (11.0%), and being uncircumcised (29.2%). Among women, elevated HIV-1 prevalence was seen in those with no formal education (36.8%) and those who received goods in exchange for sex (36.0%). More than 97% of volunteers expressed a willingness to participate in future HIV-1 studies requiring semiannual visits. HIV prevention efforts have been implemented, along with further research to characterize this population for future cohort feasibility studies and HIV-1 vaccine efficacy trials.