A social vaccine? Social and structural contexts of HIV vaccine acceptability among most-at-risk populations in Thailand

Acceptability of a Future HIV Vaccine: A Rapid Scoping Review

BACKGROUND

A HIV vaccine is not available yet, but perceptions of HIV vaccines will be important to explore before their roll-out for effective vaccine promotion. This article presents the findings of a rapid scoping review of the literature to identify individual, social, and vaccine-related factors associated with the acceptability of a future HIV vaccine.

METHODS

We searched 5 databases (Medline OVID, Embase, PsycINFO, Web of Science, and Cochrane) using relevant keywords and Medical Subject Headings. All articles, regardless of study design, publication year, and geographic location, were included if they examined HIV vaccine acceptability and its underlying factors.

RESULTS

We retrieved 2386 unique articles, of which 76 were included in the final review. Perceived benefits (34.2%) and perceived susceptibility (25.0%) were primary individual factors of HIV vaccine acceptability. Misinformation (17.1%) and distrust (22.4%) regarding future HIV vaccines, HIV stigma (30.3%), and social support (10.5%) were social factors of HIV vaccine acceptability. Vaccine efficacy (42.1%), cost (28.9%), and side effects (67.1%) were common vaccine characteristics influencing HIV vaccine acceptability. Altruism (10.5%) and risk compensation (26.3%) were also key factors.

CONCLUSIONS

Our analyses revealed that skeptical beliefs, negative perceptions, and misconceptions about HIV vaccines are real barriers to their acceptability. To alleviate HIV vaccine hesitancy and address trust concerns, strategic vaccine communication should be disseminated by trustworthy sources. Messages should impart accurate vaccine information and emphasize both individual and social benefits of HIV vaccination, as well as leverage social support in increasing willingness to get a future HIV vaccine.

Uptake of HIV testing and its correlates among sexually experienced college students in Southwestern, China: a Web-Based online cross-sectional study

BACKGROUND

The prevalence of human immunodeficiency virus (HIV) is becoming more common among college students in China. However, latest data on the prevalence and correlates of HIV testing among sexually experienced college students is rarely.

METHODS

An online survey was conducted among college students aged 18 years or older using multistage stratified cluster sampling from 16 colleges. Data on socio-demographic, HIV testing, HIV-related awareness, attitudes, sexual education and behaviors were collected. Propensity score matching (PSM) and logistic regression model were used to identify factors associated with HIV testing.

RESULT

A total of 108,987 students participated the survey, of which 13,201 sexually experienced college students were included in this study. 1,939 (14.69%) college students with sexual experience reported uptake of HIV testing in the preceding year. The uptake of HIV testing increased for college students with a rising HIV knowledge score and sexual health knowledge. Being awareness of HIV-related knowledge (aOR = 1.15, 95%CI: 1.01-1.30), accepting one-night stands (aOR = 1.16, 95%CI:1.03-1.32), obtaining satisfactory sexual interpretation from parent(s) (aOR = 1.24, 95%CI: 1.07-1.43), ever had unintended pregnancy (aOR = 1.78, 95%CI: 1.32-2.38), ever had received HIV-related preventive service(s) (aOR = 1.37, 95%CI: 1.10-1.70), ever had participated HIV-related preventive services (aOR = 3.76, 95%CI: 2.99-4.75) and ever had anal sex (aOR = 2.66, 95%CI: 2.11-3.34) were positively associated with uptake of HIV testing. However, accepting premarital sex (aOR = 0.76, 95%CI: 0.66-0.88), accepting cohabitation (aOR = 0.75, 95%CI: 0.61-0.92), occasionally discussing sex with parent(s) (aOR = 0.68, 95%CI: 0.50-0.91), and being with moderate satisfaction of school sex courses (aOR = 0.74, 95%CI: 0.58-0.95) were negatively associated with uptake of HIV testing.

CONCLUSION

The prevalence of HIV testing was relatively low. Participation in HIV-related services and high-risk sexual behaviors were important enablers for testing. Improving sex education for students, increasing HIV preventive services on campus, and improving family sex education are necessary to increase HIV testing among college sexually experienced students.

NIHR Global Health Research Group on Vaccines for vulnerable people in Africa (VAnguard): Concept and Launch event report

Background

Vaccination is an important public health intervention, but not everyone benefits equally. Biological, social and structural factors render some communities vulnerable and unable to secure optimal health benefits from vaccination programmes. This drives health inequity and undermines wider vaccine impact by allowing the persistence of non-immune communities as foci for recurrent disease outbreaks. The NIHR Global Health Research Group on Vaccines for vulnerable people in Africa (VAnguard) aims to understand how biological, social, and structural factors interact to impair vaccine impact in vulnerable African communities.

Methods

The VAnguard project will be implemented through three thematic work packages (1-3) and four cross-cutting work packages (4-7). Work package 1 will investigate the biological drivers and mechanisms of population differences in vaccine responses. Work package 2 will support the understanding of how structural, social and biological determinants of vaccine response interrelate to determine vaccine impact. Work package 3 will synthesise data and lead analyses to develop, model and test community-based integrated strategies to optimise vaccine access, uptake and effectiveness. Work package 4 will plan and implement field investigations (community survey and qualitative studies (with support of work package 2) to explore structural, social & biological determinants impairing vaccine impact. Work package 5 will collaborate with work packages 1-4, to engage communities in designing interventions that aim to directly optimise vaccine impact through a process of co-learning and co-creation between them and the researchers. Work package 6 will build capacity for, and a culture of, consultative, collaborative multidisciplinary vaccine research in East Africa. Work package 7 will support the overall project management and governance. Following the project inception on the 1 st of September 2022, project launch was held in November 2022.

Conclusion

Results from this project will contribute to the development of integrated strategies that will optimise vaccine benefits and drive health equity.

The impact of financial incentives on HIV incidence among adolescent girls and young women in Eswatini: Sitakhela Likusasa, a cluster randomised trial

INTRODUCTION

Incentives conditional on school attendance or on remaining free of sexually transmitted infections have produced mixed results in reducing HIV incidence.

METHODS

HIV-negative adolescent girls and young women aged 15-22%-50% of whom were out of school-were recruited from 293 clusters in Eswatini from urban (30%) and rural areas (70%).Financial incentives conditional on education attendance were randomly allocated at the cluster level. All participants were further individually randomised into eligibility for a raffle incentive conditional on random selection into the raffle, on negative tests for syphilis and Trichomonas vaginalis and on being a raffle winner, creating four subarms in a 2×2 factorial design: no-intervention, raffle incentive, education incentive and raffle & education incentive. Randomisation was unblinded to participants.Logistic regressions were used in intention-to-treat analysis of HIV incidence over 3 years to estimate the impact of incentives conditional on school attendance and raffle incentives conditional on remaining sexually transmitted infection free.

RESULTS

The study recruited 4389 HIV-negative participants, who were distributed into four subarms: no intervention (n=1068), raffle incentive (n=1162), education incentive (n=1088) and raffle and education incentive (n=1071).At endline, 272 participants from 3772 for whom endline data were collected, tested positive for HIV. HIV incidence among participants in education treatment arm was significantly lower than in the education control arm, 6.34% (119/1878) versus 8.08% (153/1894) (p=0.041); OR: 0.766 (0.598 to 0.981); adjusted OR (aOR): 0.754 (0.585 to 0.972). Compared with the no intervention subarm, HIV incidence in the raffle and education incentive subarm was significantly lower, 5.79% (54/878) versus 8.84% (80/905); OR: 0.634 (0.443 to 0.907); aOR: 0.622 (0.433 to 0.893), while it was not significantly lower in the raffle incentive subarm.

CONCLUSION

Financial incentives conditional on education participation significantly reduced HIV infection among adolescent girls and young women in Eswatini and appear to be a promising tool for prevention in high HIV prevalence settings.

TRIAL REGISTRATION NUMBER

Western Institutional Review Board-protocol number 20 141 630.Eswatini National Health Research Review Board-FWA00026661.Pan African Clinical Trials Registry-PACTR201811609257043.

LGBT+ inclusion and human rights in Thailand: a scoping review of the literature

Background

Globally, LGBT+ people continue to struggle to achieve full realization of their human rights. Amid reported health and mental health disparities, and economic insecurity, we conducted a scoping review to explore the breadth of the literature, map and summarize the evidence, and identify knowledge gaps on LGBT+ inclusion and human rights in Thailand.

Methods

We conducted a scoping review in accordance with the methodology developed by the Joanna Briggs Institute and PRISMA-ScR guidelines. We systematically searched 16 databases for peer-reviewed literature, and government and nongovernmental organization websites for grey literature, published in English or Thai from January 1, 2000–August 21, 2020. Two reviewers independently screened studies according to pre-set criteria. We abstracted and analyzed data on publication characteristics and focal populations, and synthesized findings in six domains of LGBT+ inclusion: political and civic participation, education, family, personal security and violence, economic well-being, and health.

Results

The review captured 3327 results in total, which was scoped to 76 peer-reviewed articles and 39 grey literature sources, the majority published after 2010. Gay men and transgender women were the primary focal populations in the peer-reviewed literature, LGBT+ people as a whole in the grey literature. Health was the predominant domain across publications. Key findings include the absence of generalized antidiscrimination legislation for LGBT+ individuals and lack of recourse for transgender individuals to change their legal gender; multifaceted stigma and discrimination in the educational system; social isolation and exclusion in families; disproportionate prevalence of sexual violence and reluctance to report to police; discrimination and marginalization in employment; and LGBT+ disparities in health and mental health.

Conclusions

Future research and programmatic initiatives on LGBT+ inclusion in Thailand should aim to address: 1) understudied populations—lesbian and bisexual women, transmasculine persons; 2) underrepresented topics, including constraints to LGBT+ advocacy; 3) strategic policy initiatives around anti-discrimination laws and legal recognition of same-sex marriage and families; and 4) the need for consistent collection of disaggregated data on LGBT+ persons in education, family, economic, personal security/violence, and health domains in order to assess indicators of inclusion and progress in advancing human rights for LGBT+ people in Thailand.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11798-2.

Social Impacts Among Participants in HIV Vaccine Trial Network (HVTN) Preventive HIV Vaccine Trials

BACKGROUND

Given the persistent stigma and discrimination against HIV worldwide, preventive HIV vaccine trials face unique challenges. Negative social impacts (NSIs)-problems that HIV vaccine trial participants face in many different spheres of their lives related to trial participation-have received a great deal of attention. Beneficial social impacts (BSIs)-perceived benefits experienced by a participant and resulting from their trial participation-are a critical component of participants' experiences, yet they have received little attention.

SETTING

All HIV Vaccine Trials Network trial participants for whom social impact data were available-8347 participants in 13 countries who enrolled in 48 phase 1, 2a, and 2b trials.

METHODS

A cross-protocol analysis to assess self-reported BSIs and NSIs related to participating in a preventive HIV vaccine trial. Data were obtained from 48 completed HIV Vaccine Trials Network vaccine trials from December 2000 to September 2017.

RESULTS

Overall, 6572 participants (81%) reported at least one BSI, and 686 participants (8%) reported 819 NSI events. Altruism/feeling good helping others was the BSI most often endorsed by study participants (43%), followed by receiving risk-reduction counseling (30%). Most NSI events (81%) were reported by US/Swiss participants, and most (79%) trial-related NSIs were negative reactions from friends, family, and partners. Of the NSIs reported, 7% were considered to have a major impact on the participant's quality of life.

CONCLUSION

Our results underscore the relatively common experiences of BSIs among preventive HIV vaccine trial participants and mirror the results of other studies that find infrequent reports of NSIs.

HIV Vaccine Preparedness among Men Who Have Sex with Men in Taiwan: Sociocultural and Behavioral Factors

In Taiwan, men who have sex with men (MSM) are at disproportionate risk of HIV infection. We examined awareness and acceptability of future HIV vaccines. From July to August 2014, we conducted a cross-sectional survey with MSM recruited through community-based organizations (CBOs) in 2 cities. Among 200 participants (mean age, 27.6 years), half reported multiple partners and one-third condomless anal sex (past 3 months); 12% were HIV-positive. Traditional Chinese medicine (TCM) use was reported by 42.7%. Over two-thirds (69.0%) were aware of HIV vaccine research, but less than half (43.8%) would accept an HIV vaccine if available. In multivariable analysis, higher educational attainment, >5 sex partners, and TCM use were positively associated with HIV vaccine awareness. Culturally informed HIV vaccine preparedness in Taiwan may be supported by a complementary approach to TCM and HIV prevention technologies, tailoring information for MSM with lower education and targeting those at high risk through gay-identified CBOs.

Caveats and pitfalls associated with researching community engagement in the context of HIV vaccine trials

HIV vaccine efficacy trials require the enrolment of large numbers of HIV-negative individuals and thus it is necessary to engage with communities where HIV incidence is high. We identify some of the caveats and pitfalls associated with researching community engagement in the context of HIV vaccine trials. These are as follows: the lack of consensus of what community engagement is and how it is practiced, the sometimes paradoxical role of community advisory boards as community representatives and challenges associated with information dissemination in communities. We identify a set of considerations for community engagement practitioners, trial investigators and social scientists when conducting community engagement.

Healthcare avoidance by people who inject drugs in Bangkok, Thailand

BACKGROUND

Although people who inject drugs (IDU) often contend with various health-related harms, timely access to health care among this population remains low. We sought to identify specific individual, social and structural factors constraining healthcare access among IDU in Bangkok, Thailand.

METHODS

Data were derived from a community-recruited sample of IDU participating in the Mitsampan Community Research Project between July and October 2011. We assessed the prevalence and correlates of healthcare avoidance due to one's drug use using multivariate logistic regression.

RESULTS

Among 437 participants, 112 (25.6%) reported avoiding health care because they were IDU. In multivariate analyses, factors independently associated with avoiding health care included having ever been drug tested by police [adjusted odds ratio (AOR) = 1.80], experienced verbal abuse (AOR = 3.15), been discouraged from engaging in usual family activities (AOR = 3.27), been refused medical care (AOR = 10.90), experienced any barriers to health care (AOR = 4.87) and received healthcare information and support at a drop-in centre (AOR = 1.92) (all P < 0.05).

CONCLUSIONS

These findings highlight the need to address the broader policy environment, which perpetuates the criminalization and stigmatization of IDU, and to expand peer-based interventions to facilitate access to health care for IDU in this setting.

HIV-Related Stigma and HIV Prevention Uptake Among Young Men Who Have Sex with Men and Transgender Women in Thailand

HIV-related stigma is a pervasive structural driver of HIV. With an HIV epidemic among young men who have sex with men (MSM) and transgender women (TG) in Thailand characterized as explosive, we conducted a cross-sectional survey among MSM and TG aged 18-30 years. From April-August 2013, participants recruited using venue-based sampling from gay entertainment sites and community-based organizations completed a tablet-assisted survey interview in Thai language. We conducted multiple logistic regression to assess correlations between HIV-related stigma (felt-normative, vicarious domains) and socio-demographic variables, HIV vulnerabilities (gay entertainment employment, sex work, forced sex history), and HIV prevention uptake (condom use, HIV testing, rectal microbicide acceptability). Among participants (n = 408), 54% identified as gay, 25% transgender, and 21% heterosexual. Two-thirds (65.7%) were employed at gay entertainment venues, 67.0% had more than three male partners (past month), 55.6% had been paid for sex, and 4.5% were HIV-positive. One-fifth (21.3%) reported forced sex. Most participants reported experiencing felt-normative and vicarious HIV-related stigma. Adjusting for socio-demographics, participants with higher total HIV-related stigma scores had significantly lower odds of HIV testing and rectal microbicide acceptability, and higher odds of having experienced forced sex. Both vicarious and felt-normative dimensions of HIV-related stigma were inversely associated with HIV testing and rectal microbicide acceptability. Our findings suggest that HIV-related stigma harms the health of HIV-negative MSM and TG at high risk for HIV infection. HIV-related interventions and research among young MSM and TG in Thailand should address multiple dimensions of HIV-related stigma as a correlate of risk and a barrier to accessing prevention.

Taking culture seriously in biomedical HIV prevention trials: a meta-synthesis of qualitative studies

A substantial gap exists between widespread acknowledgement of the importance of incorporating cultural sensitivity in biomedical HIV prevention trials and empirical evidence to guide the operationalization of cultural sensitivity in these trials. We conducted a systematic literature search and qualitative meta-synthesis to explore how culture is conceptualized and operationalized in global biomedical HIV prevention trials. Across 29 studies, the majority (n = 17) were conducted in resource-limited settings. We identified four overarching themes: (1) semantic cultural sensitivity - challenges in communicating scientific terminology into local vernaculars; (2) instrumental cultural sensitivity - understanding historical experiences to guide tailoring of trial activities; (3) budgetary, logistical, and personnel implications of operationalizing cultural sensitivity; and (4) culture as an asset. Future investigations should address how sociocultural considerations are operationalized across the spectrum of trial preparedness, implementation, and dissemination in particular sociocultural contexts, including intervention studies and evaluations of the effectiveness of methods used to operationalize culturally sensitive practices.

Relationship-level analysis of drug users' anticipated changes in risk behavior following HIV vaccination

Formative research into the behavioral factors surrounding HIV vaccine uptake is becoming increasingly important as progress is made in HIV vaccine development. Given that the first vaccines on the market are likely to be partially effective, risk compensation (i.e., increased risk behavior following vaccination) may present a concern. This study characterized the relationships in which HIV vaccine-related risk compensation is most likely to occur using dyadic data collected from people who use drugs, a high-risk group markedly underrepresented in extant literature. Data were collected from 433 drug users enrolled in a longitudinal study in the USA. Respondents were asked to provide the first name and last initial of individuals with whom they had injected drugs and/or had sex during the past six months. For each partner, respondents reported their likelihood of increasing risk behavior if they and/or their partner received an HIV vaccine. Using generalized linear mixed models, relationship-level correlates to risk compensation were examined. In bivariate analysis, risk compensation was more likely to occur between partners who have known each other for a shorter time (odds ratio [OR]=0.95, 95% confidence interval [CI]: 0.90-0.99, p=0.028) and between those who inject drugs and have sex together (OR=2.52, CI: 1.05-6.04, p=0.039). In relationships involving risk compensation, 37% involved partners who had known each other for a year or less compared to only 13% of relationships not involving risk compensation. Adjusting for other variables, duration (OR: 0.95, CI: 0.90-1.00, p=0.033) was associated with risk compensation intent. These analyses suggest that risk compensation may be more likely to occur in less established relationships and between partners engaging in more than one type of risk behavior. These data provide further support for the need to expand measures of risk compensation in HIV vaccine preparedness studies to assess not only if people will change their behavior, but also with whom.

Drug users' willingness to encourage social, sexual, and drug network members to receive an HIV vaccine: a social network analysis

This study examined feasibility of peer-based promotion of HIV vaccination and dyadic correlates to vaccine encouragement in risk- and non-risk networks of drug users (n = 433) in the US. Data were collected on HIV vaccine attitudes, risk compensation intentions, likelihood of encouraging vaccination, and recent (past 6 months) risk (i.e. involving sex and/or injecting drugs) and non-risk (i.e. involving co-usage of noninjected drugs and/or social support) relationships. Willingness to encourage HIV vaccination was reported in 521 and 555 risk- and non-risk relationships, respectively. However, 37 % expressed hesitancy, typically due to fear of side effects or social concerns. Encouragement was often motivated by perceived HIV risk, though 9 % were motivated by risk compensation intentions. In non-risk partnerships, encouragement was associated with drug co-usage, and in risk relationships, with perceived vaccine acceptability and encouragement by the partner. Network-based HIV vaccine promotion may be a successful strategy, but risk compensation intentions should be explored.

Development of an HIV vaccine attitudes scale to predict HIV vaccine acceptability among vulnerable populations: L.A. VOICES

BACKGROUND

Decade-long delays in successful implementation of Hepatitis B vaccines and ongoing obstacles in HPV vaccine roll-out suggest the importance of an implementation science approach to prepare for the effective translation of future HIV vaccines from clinical trials into routine practice. The objective of this study was to test HIV vaccine attitude items to develop reliable scales and to examine their association with HIV vaccine acceptability.

METHODS

HIV vaccine attitude items were assessed as part of the L.A. VOICES survey, a large-scale study conducted among underserved residents of Los Angeles, to identify factors that may influence HIV vaccine acceptability. Participants (n=1225) were randomly selected from public STD clinics, needle exchange sites and Latino community clinics using three-stage, venue-based time space sampling.

RESULTS

Exploratory factor analysis across 20 items revealed four distinct factors - mistrust, HIV vaccine social concerns, risk compensation, and altruistic vaccination - with acceptable reliability coefficients for each subscale (Cronbach's α range 0.61-0.84). We found no significant differences in reliability by gender or by vaccine acceptability. Risk compensation (odds ratio (OR)=1.49; 95% CI=[1.18, 1.89]; p=0.001) and altruistic vaccination (OR=1.40; 95% CI=[1.14, 1.71]; p=0.001) were significantly and positively associated with HIV vaccine acceptability.

CONCLUSIONS

We identified four HIV vaccine attitude scales with sound internal reliability parameters. In the aftermath of the first candidate vaccine to demonstrate efficacy against HIV infection, these scales may be helpful in bridging expectable research-to-practice gaps in future HIV vaccine dissemination among populations at risk. As HIV vaccine trials progress in the United States and globally, these measures also may be useful as a tool to assess and facilitate effective responses to community concerns about HIV vaccine trials and to target interventions to support recruitment and mitigate risk compensation.

Will HIV vaccination reshape HIV risk behavior networks? A social network analysis of drug users' anticipated risk compensation

BACKGROUND

An HIV vaccine could substantially impact the epidemic. However, risk compensation (RC), or post-vaccination increase in risk behavior, could present a major challenge. The methodology used in previous studies of risk compensation has been almost exclusively individual-level in focus, and has not explored how increased risk behavior could affect the connectivity of risk networks. This study examined the impact of anticipated HIV vaccine-related RC on the structure of high-risk drug users' sexual and injection risk network.

METHODS

A sample of 433 rural drug users in the US provided data on their risk relationships (i.e., those involving recent unprotected sex and/or injection equipment sharing). Dyad-specific data were collected on likelihood of increasing/initiating risk behavior if they, their partner, or they and their partner received an HIV vaccine. Using these data and social network analysis, a "post-vaccination network" was constructed and compared to the current network on measures relevant to HIV transmission, including network size, cohesiveness (e.g., diameter, component structure, density), and centrality.

RESULTS

Participants reported 488 risk relationships. Few reported an intention to decrease condom use or increase equipment sharing (4% and 1%, respectively). RC intent was reported in 30 existing risk relationships and vaccination was anticipated to elicit the formation of five new relationships. RC resulted in a 5% increase in risk network size (n = 142 to n = 149) and a significant increase in network density. The initiation of risk relationships resulted in the connection of otherwise disconnected network components, with the largest doubling in size from five to ten.

CONCLUSIONS

This study demonstrates a new methodological approach to studying RC and reveals that behavior change following HIV vaccination could potentially impact risk network connectivity. These data will be valuable in parameterizing future network models that can determine if network-level change precipitated by RC would appreciably impact the vaccine's population-level effectiveness.

HIV vaccine acceptability among high-risk drug users in Appalachia: a cross-sectional study

Background

A vaccine could substantially impact the HIV epidemic, but inadequate uptake is a serious concern. Unfortunately, people who use drugs, particularly those residing in rural communities, have been underrepresented in previous research on HIV vaccine acceptability. This study examined HIV vaccine acceptability among high-risk drug users in a rural community in the United States.

Methods

Interviewer-administered questionnaires included questions about risk behavior and attitudes toward HIV vaccination from 433 HIV-negative drug users (76% with history of injection) enrolled in a cohort study in Central Appalachia. HIV vaccine acceptability was measured on a 4-point Likert scale. Generalized linear mixed models were used to determine correlates to self-report of being “very likely” to receive a 90% effective HIV vaccine (i.e. “maximum vaccine acceptability”, or MVA). Adjusted odds ratios (AORs) and corresponding 95% confidence intervals (CIs) are reported.

Results

Most (91%) reported that they would accept a preventive HIV vaccine, but concerns about cost, dosing, transportation constraints, vaccine-induced seropositivity, and confidentiality were expressed. Cash incentives, oral-administration, and peer/partner encouragement were anticipated facilitators of uptake. In multivariate analysis, men were significantly less likely to report MVA (AOR: 0.33, CI: 0.21 – 0.52). MVA was more common among participants who believed that they were susceptible to HIV (AOR: 2.31, CI: 1.28 – 4.07), that an HIV vaccine would benefit them (AOR: 2.80, CI: 1.70 – 4.64), and who had positive experiential attitudes toward HIV vaccination (AOR: 1.85, CI: 1.08 – 3.17). MVA was also more common among participants who believed that others would encourage them to get vaccinated and anticipated that their behavior would be influenced by others' encouragement (AOR: 1.81, 95% 1.09 – 3.01).

Conclusions

To our knowledge, this study was among the first to explore and provide evidence for feasibility of HIV vaccination in a rural, high-risk population in the United States. This study provides preliminary evidence that gender-specific targeting in vaccine promotion may be necessary to promoting vaccine uptake in this setting, particularly among men. The data also underscore the importance of addressing perceived risks and benefits, social norms, and logistical constraints in efforts to achieve widespread vaccine coverage in this high-risk population.

An HIV Vaccine for South-East Asia-Opportunities and Challenges

Recent advances in HIV vaccine development along with a better understanding of the immune correlates of risk have emerged from the RV144 efficacy trial conducted in Thailand. Epidemiological data suggest that CRF01_AE is still predominant in South-East Asia and is spreading in China with a growing number of circulating recombinant forms due to increasing human contact, particularly in large urban centers, tourist locations and in sites of common infrastructure. A vaccine countering CRF01_AE is a priority for the region. An Asia HIV vaccine against expanding B/E or BCE recombinant forms should be actively pursued. A major challenge that remains is the conduct of efficacy trials in heterosexual populations in this region. Men who have sex with men represent the main target population for future efficacy trials in Asia. Coupling HIV vaccines with other prevention modalities in efficacy trials might also be envisaged. These new avenues will only be made possible through the conduct of large-scale efficacy trials, interdisciplinary teams, international collaborations, and strong political and community commitments.

A social ecology of rectal microbicide acceptability among young men who have sex with men and transgender women in Thailand

INTRODUCTION

With HIV-incidence among men who have sex with men (MSM) in Bangkok among the highest in the world, a topical rectal microbicide would be a tremendous asset to prevention. Nevertheless, ubiquitous gaps between clinical trial efficacy and real-world effectiveness of existing HIV preventive interventions highlight the need to address multi-level factors that may impact on rectal microbicide implementation. We explored the social ecology of rectal microbicide acceptability among MSM and transgender women in Chiang Mai and Pattaya, Thailand.

METHODS

We used a qualitative approach guided by a social ecological model. Five focus groups were conducted in Thai using a semi-structured interview guide. All interviews were digitally recorded, transcribed verbatim in Thai and translated into English. We conducted thematic analysis using line-by-line and axial coding and a constant comparative method. Transcripts and codes were uploaded into a customized database programmed in Microsoft Access. We then used content analysis to calculate theme frequencies by group, and Chi-square tests and Fisher's exact test to compare themes by sexual orientation/gender expression and age.

RESULTS

Participant's (n=37) mean age was 24.8 years (SD=4.2). The majority (70.3%) self-identified as gay, 24.3% transgender women. Product-level themes (side effects, formulation, efficacy, scent, etc.) accounted for 42%, individual (increased sexual risk, packaging/portability, timing/duration of protection) 29%, interpersonal (trust/communication, power/negotiation, stealth) 8% and social-structural (cost, access, community influence, stigma) 21% of total codes, with significant differences by sexual orientation/gender identity. The intersections of multi-level influences included product formulation and timing of use preferences contingent on interpersonal communication and partner type, in the context of constraints posed by stigma, venues for access and cost.

DISCUSSION

The intersecting influence of multi-level factors on rectal microbicide acceptability suggests that social-structural interventions to ensure widespread access, low cost and to mitigate stigma and discrimination against gay and other MSM and transgender women in the Thai health care system and broader society will support the effectiveness of rectal microbicides, in combination with other prevention technologies, in reducing HIV transmission. Education, outreach and small-group interventions that acknowledge differences between MSM and transgender women may support rectal microbicide implementation among most-at-risk populations in Thailand.

The marginal willingness-to-pay for attributes of a hypothetical HIV vaccine

This paper estimates the marginal willingness-to-pay for attributes of a hypothetical HIV vaccine using discrete choice modeling. We use primary data from 326 respondents from Bangkok and Chiang Mai, Thailand, in 2008-2009, selected using purposive, venue-based sampling across two strata. Participants completed a structured questionnaire and full rank discrete choice modeling task administered using computer-assisted personal interviewing. The choice experiment was used to rank eight hypothetical HIV vaccine scenarios, with each scenario comprising seven attributes (including cost) each of which had two levels. The data were analyzed in two alternative specifications: (1) best-worst; and (2) full-rank, using logit likelihood functions estimated with custom routines in Gauss matrix programming language. In the full-rank specification, all vaccine attributes are significant predictors of probability of vaccine choice. The biomedical attributes of the hypothetical HIV vaccine (efficacy, absence of VISP, absence of side effects, and duration of effect) are the most important attributes for HIV vaccine choice. On average respondents are more than twice as likely to accept a vaccine with 99% efficacy, than a vaccine with 50% efficacy. This translates to a willingness to pay US$383 more for a high efficacy vaccine compared with the low efficacy vaccine. Knowledge of the relative importance of determinants of HIV vaccine acceptability is important to ensure the success of future vaccination programs. Future acceptability studies of hypothetical HIV vaccines should use more finely grained biomedical attributes, and could also improve the external validity of results by including more levels of the cost attribute.