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

Caregiver preferences and willingness-to-pay for home care services for older people with dementia: A discrete choice experiment in the Milan metropolitan area

OBJECTIVES

Dementia is a major health and social care challenge in high-income countries where most people are cared for in their own homes. This study aimed to elicit caregiver preferences for alternative bundles of home care services in the Milan metropolitan area.

METHODS

A binary discrete choice experiment was administered to a sample of informal caregivers of people with dementia recruited through a network of non-profit organizations. The experiment included four attributes: 1) number of home care hours per month; 2) type of care; 3) caregiver peer support group organization; 4) monthly family's cost (in euros), each articulated into three levels. A mixed logit model was applied to analyze the responses using Stata.

RESULTS

A total of 93 self-administered questionnaires were collected in January-April 2023. Two-thirds of both caregivers (67.7 %) and care recipients (65.6 %) were female, with a mean age of 59.0 (±12.1) years and 82.2 (±6.5) years, respectively. The experiment showed that increased home care hours, mixed health and social home care, caregiver meetings with professional support and lower monthly costs were mostly valued by caregivers. Some preference heterogeneity was detected in relation to care recipient's characteristics (e.g., age).

CONCLUSIONS

These results are expected to inform policymakers about caregiver priorities in the field of dementia based on the values placed on hypothetical public home care services.

Stated preferences for new HIV prevention technologies among men who have sex with men in India: A discrete choice experiment

INTRODUCTION

India has the second largest HIV epidemic in the world. Despite successes in epidemic control at the population level, a concentrated epidemic persists among gay and other men who have sex with men (MSM). However, India lags in implementation of biomedical prevention technologies, such as HIV pre-exposure prophylaxis (PrEP). In order to inform scale-up of new HIV prevention technologies, including those in the development pipeline, we assessed willingness to use oral PrEP, rectal microbicides, and HIV vaccines, and choices among product characteristics, among MSM in two major Indian cities.

METHODS

A cross-sectional survey was conducted with a discrete choice experiment (DCE), an established methodology for quantitively estimating end-user preferences in healthcare. Survey participants were randomly assigned to one of three questionnaire versions, each of which included a DCE for one prevention technology. Participants were recruited using chain-referral sampling by peer outreach workers, beginning with seeds in community-based organizations and public sex environments, in Chennai and Mumbai. DCE data were analyzed using random-parameters (mixed) logit (RPL) models.

RESULTS

Among participants (n = 600), median age was 25 years, with median monthly income of INR 9,000 (~US$125). Nearly one-third (32%) had completed a college degree and 82% were single/never married. A majority of participants (63%) reported condomless anal sex in the past month. The acceptability of all three products was universally high (≥90%). Across all three products, four attributes were significant predictors of acceptability-with efficacy consistently the most important attribute, and in decreasing order of preference, side-effects, dosing schedule, and venue. MSM varied in their preferences for product attributes in relation to their levels of education and income, and engagement in sex work and HIV risk behavior.

CONCLUSION

This study provides empirical evidence to facilitate the integration of end users' preferences throughout design, testing, and dissemination phases of HIV prevention technologies. The findings also suggest action points and targets for interventions for diverse subgroups to support the effectiveness of combination HIV prevention among MSM in India.

Freebie Seekers or Desperate Buyers? An Analysis of Willingness to Pay for COVID-19 Vaccine in Türkiye

The aim of the study is to determine the level of price that individuals living in Türkiye are willing to pay (WTP) for a hypothetical COVID-19 vaccine. In addition, the study also aims to identify the socioeconomic factors affecting that level of WTP. The data is collected via a virtually applied questionnaire. Probit estimations are employed to determine the level of price that is willing to be paid. Further, the socioeconomic factors affecting the revealed WTP level are identified with an ordered-probit estimation strategy. The average price level that the participants are willing to pay for two doses of a hypothetical COVID-19 vaccine which immunes for 12 months is ₺316.93 ($42.66). Higher education groups, public employees, married people, and urban individuals are more likely to pay at higher price levels of hypothetical COVID-19 vaccine. Interestingly, the individuals living with a pregnant woman or a baby, the ones who experienced severe COVID-19 disease and the ones who already decided to be vaccinated are more likely to pay at relatively low-price levels. This study may contribute to broader literature as it will provide evidence from Türkiye for international comparisons.

Vaccine decision making in New Zealand: a discrete choice experiment

BACKGROUND

Vaccine hesitancy is a significant threat to global health. A key part of addressing hesitancy is to ensure that public health messaging prioritises information that is considered important to the public. This study aimed to examine how different vaccine characteristics affect public preferences for vaccines in New Zealand, what trade-offs they are willing to make between different vaccine characteristics, and how their preferences are affected by their vaccine-related conspiracy beliefs and COVID-19 vaccination status.

METHODS

An online discrete choice experiment (DCE) was designed to elicit individual preferences about vaccines using the 1000minds platform. Members of the general population of New Zealand aged ≥ 18 years were invited to complete the DCE. Participants were asked to indicate their preference between two options showing different combinations of vaccine characteristics. Data on sociodemographic characteristics were collected. Beliefs were measured using the vaccine conspiracy beliefs scale (VCBS) with scores ≥ 19 indicating strong vaccine-related conspiracy beliefs. The DCE was analysed using the PAPRIKA method (Potentially All Pairwise RanKings of all possible Alternatives) and preferences compared between respondents with high versus low VCBS scores and vaccinated versus unvaccinated respondents for COVID-19.

RESULTS

A total of 611 respondents from 15 regions completed the DCE. Mean (SD) age was 45.9 (14.7) years with most having had 2 or more doses of the coronavirus vaccine (86%). Mean (SD) VCBS score was 18.5 (12.4) indicating moderate vaccine-related conspiracy beliefs. Risk of severe adverse effects was the most highly valued vaccine characteristic, followed by vaccine effectiveness and duration of protection. Vaccine origin and route of administration were ranked least important. Respondents scoring high on the VCBS placed less value on the effectiveness of vaccines but greater value on development time and total number of doses (p < 0.001). COVID-19 unvaccinated respondents ranked development time and total number of doses more highly than those vaccinated respondents (p < 0.001).

CONCLUSIONS

Risk of severe adverse effects, vaccine effectiveness and duration of protection were rated by the New Zealand public as the top three most important vaccine characteristics. This information is important for informing public health messaging to promote vaccine uptake and inform vaccine decision-making.

Divergent preferences for enhanced HIV testing options among high-risk populations in northern Tanzania: a short report

To achieve the UNAIDS target of diagnosing 95% of all persons living with HIV, enhanced HIV testing services with greater attractional value need to be developed and implemented. We conducted a discrete choice experiment (DCE) to quantify preferences for enhanced HIV testing features across two high-risk populations in the Kilimanjaro Region in northern Tanzania. We designed and fielded a survey with 12 choice tasks to systematically recruited female barworkers and male mountain porters. Key enhanced features included: testing availability on every day of the week, an oral test, integration of a general health check or an examination for sexually transmitted infections (STI) with HIV testing, and provider-assisted confidential partner notification in the event of a positive HIV test result. Across 300 barworkers and 440 porters surveyed, mixed logit analyses of 17,760 choices indicated strong preferences for everyday testing availability, health checks, and STI examinations. Most participants were averse to oral testing and confidential partner notification by providers. Substantial preference heterogeneity was observed within each risk group. Enhancing HIV testing services to include options for everyday testing, general health checks, and STI examinations may increase the appeal of HIV testing offers to high-risk populations.Trial registration: ClinicalTrials.gov identifier: NCT02714140.

Health Economics Research on Non-surgical Biomedical HIV Prevention: Identifying Gaps and Proposing a Way Forward

BACKGROUND AND OBJECTIVE

Although HIV prevention science has advanced over the last four decades, evidence suggests that prevention technologies do not always reach their full potential. Critical health economics evidence at appropriate decision-making junctures, particularly early in the development process, could help identify and address potential barriers to the eventual uptake of future HIV prevention products. This paper aims to identify key evidence gaps and propose health economics research priorities for the field of HIV non-surgical biomedical prevention.

METHODS

We used a mixed-methods approach with three distinct components: (i) three systematic literature reviews (costs and cost effectiveness, HIV transmission modelling and quantitative preference elicitation) to understand health economics evidence and gaps in the peer-reviewed literature; (ii) an online survey with researchers working in this field to capture gaps in yet-to-be published research (recently completed, ongoing and future); and (iii) a stakeholder meeting with key global and national players in HIV prevention, including experts in product development, health economics research and policy uptake, to uncover further gaps, as well as to elicit views on priorities and recommendations based on (i) and (ii).

RESULTS

Gaps in the scope of available health economics evidence were identified. Little research has been carried out on certain key populations (e.g. transgender people and people who inject drugs) and other vulnerable groups (e.g. pregnant people and people who breastfeed). Research is also lacking on preferences of community actors who often influence or enable access to health services among priority populations. Oral pre-exposure prophylaxis, which has been rolled out in many settings, has been studied in depth. However, research on newer promising technologies, such as long-acting pre-exposure prophylaxis formulations, broadly neutralising antibodies and multipurpose prevention technologies, is lacking. Interventions focussing on reducing intravenous and vertical transmission are also understudied. A disproportionate amount of evidence on low- and middle-income countries comes from two countries (South Africa and Kenya); evidence from other countries in sub-Saharan Africa as well as other low- and middle-income countries is needed. Further, data are needed on non-facility-based service delivery modalities, integrated service delivery and ancillary services. Key methodological gaps were also identified. An emphasis on equity and representation of heterogeneous populations was lacking. Research rarely acknowledged the complex and dynamic use of prevention technologies over time. Greater efforts are needed to collect primary data, quantify uncertainty, systematically compare the full range of prevention options available, and validate pilot and modelling data once interventions are scaled up. Clarity on appropriate cost-effectiveness outcome measures and thresholds is also lacking. Lastly, research often fails to reflect policy-relevant questions and approaches.

CONCLUSIONS

Despite a large body of health economics evidence on non-surgical biomedical HIV prevention technologies, important gaps in the scope of evidence and methodology remain. To ensure that high-quality research influences key decision-making junctures and facilitates the delivery of prevention products in a way that maximises impact, we make five broad recommendations related to: improved study design, an increased focus on service delivery, greater community and stakeholder engagement, the fostering of an active network of partners across sectors and an enhanced application of research.

Attribute nonattendance in COVID-19 vaccine choice: A discrete choice experiment based on Chinese public preference

Objectives

The global coronavirus disease 2019 (COVID‐19) pandemic has not been well controlled, and vaccination could be an effective way to prevent this pandemic. By accommodating attribute nonattendance (ANA) in a discrete choice experiment (DCE), this paper aimed to examine Chinese public preferences and willingness to pay (WTP) for COVID‐19 vaccine attributes, especially the influence of ANA on the estimated results.

Methods

A DCE was designed with four attributes: effectiveness, protection period, adverse reactions and price. A random parameter logit model with an error component (RPL‐EC) was used to analyse the heterogeneity of respondents' preferences for COVID‐19 vaccine attributes. Two equality constraint latent class (ECLC) models were used to consider the influence of ANA on the estimated results in which the ECLC‐homogeneity model considered only ANA and the ECLC‐heterogeneity model considered both ANA and preference heterogeneity.

Results

Data from 1,576 samples were included in the analyses. Effectiveness had the highest relative importance, followed by adverse reactions and protection period, which were determined by the attributes and levels presented in this study. The ECLC‐heterogeneity model improved the goodness of fit of the model and obtained a lower probability of ANA. In the ECLC‐heterogeneity model, only a small number of respondents (29.09%) considered all attributes, and price was the most easily ignored attribute (64.23%). Compared with the RPL‐EC model, the ECLC‐homogeneity model obtained lower WTPs for COVID‐19 vaccine attributes, and the ECLC‐heterogeneity model obtained mixed WTP results. In the ECLC‐heterogeneity model, preference group 1 obtained higher WTPs, and preference groups 2 and 3 obtained lower WTPs.

Conclusions

The RPL‐EC, ECLC‐homogeneity and ECLC‐heterogeneity models obtained inconsistent WTPs for COVID‐19 vaccine attributes. The study found that the results of the ECLC‐heterogeneity model considering both ANA and preference heterogeneity may be more plausible because ANA and low preference may be confused in the ECLC‐homogeneity model and the RPL‐EC model. The results showed that the probability of ANA was still high in the ECLC‐heterogeneity model, although it was lower than that in the ECLC‐homogeneity model. Therefore, in future research on DCE (such as the field of vaccines), ANA should be considered as an essential issue.

Public Contribution

Chinese adults from 31 provinces in mainland China participated in the study. All participants completed the COVID‐19 vaccine choice questions generated through the DCE design.

Preferences regarding emerging HIV prevention technologies among Toronto men who have sex with men: a discrete choice experiment

New forms of HIV pre-exposure prophylaxis (PrEP) include long-acting injectables and topical microbicides, each with unique attributes that may appeal to distinct users. We used a discrete choice experiment to characterize preferences for new PrEP formulations among Toronto men who have sex with men. MSM undergoing anonymous HIV testing completed a discrete choice experiment with 12 choice sets by selecting their preferred option within each set. Each set included “usual methods to prevent HIV” (excluding PrEP) as one alternative and two hypothetical PrEP alternatives, which differed according formulation/dosing, side effects (none/mild), risk of drug resistance (none/low/moderate), and HIV prevention efficacy (50%, 65%, 80% or 99% risk reduction). We used mixed logistic regression to infer preferences for PrEP attributes and calculate the marginal rate of substitution between efficacy and other PrEP attributes. 306 men with median (interquartile range) age = 29 (25, 36) years participated, and reported 6 (3, 10) partners and 0 (0, 2) condomless receptive anal sex acts in the preceding six months. An on-demand pill was the most preferred formulation, followed by a monthly injection, daily pill, and on-demand rectal gel. Drug resistance was an important determinant of preferences if the risk was moderate, but not if it was low. The minimum efficacy required for an on-demand pill to be preferred over no PrEP was 32.6% (95%CI = 21.2–43.9%); for a daily pill, injections, and rectal gel, minimum efficacy was 57.9% (95%CI = 44.1–71.7%), 40.1% (27.0–53.2%), and 71.3% (60.5–82.1%), respectively. Attitudes towards PrEP formulations vary among men who have sex with men, with on-demand pills and monthly injections having the highest average preference scores. Understanding these preferences may help to predict uptake.

Willingness to Use Pre-exposure Prophylaxis (PrEP) and Preferences Among Men Who have Sex with Men in Mumbai and Chennai, India: A Discrete Choice Experiment

Pre-exposure prophylaxis (PrEP) programs are planned for key populations in India. We examined PrEP awareness and willingness to use PrEP in order to support products and services for MSM. From December 2016 to March 2017, we conducted a survey and discrete choice experiment (DCE)-a technique to quantify the strength of participants' trade-off preferences among various product attributes-to assess willingness to use PrEP and related preferences. MSM were recruited from cruising sites and HIV prevention services in Mumbai and Chennai. DCE data were analyzed using mixed logit regression models and estimated marginal willingness-to-pay, the relative value participants' place on different PrEP attributes. Overall, 76.6% indicated willingness to use PrEP. Efficacy had the greatest effect on choice (high vs. moderate, aOR = 19.9; 95% CI 13.0-30.4), followed by dosing frequency (intermittent vs. daily regimen, aOR = 2.02; 95% CI 1.8-2.2). Participants preferred no (vs. minor) side-effects, subsidized (vs. market) price, and government (vs. private) hospitals. Findings suggest that educational and social marketing interventions should emphasize PrEP's high efficacy and minimal side effects, and programs should provide government-subsidized PrEP with choices of intermittent or daily dosing delivered by government and private hospitals/clinics in order to optimize PrEP uptake among MSM in India.

What factors influence HIV testing? Modeling preference heterogeneity using latent classes and class-independent random effects

Efforts to eliminate the HIV epidemic will require increased HIV testing rates among high-risk populations. To inform the design of HIV testing interventions, a discrete choice experiment (DCE) with six policy-relevant attributes of HIV testing options elicited the testing preferences of 300 female barworkers and 440 male Kilimanjaro mountain porters in northern Tanzania. Surveys were administered between September 2017 and July 2018. Participants were asked to complete 12 choice tasks, each involving first- and second-best choices from 3 testing options. DCE responses were analyzed using a random effects latent class logit (RELCL) model, in which the latent classes summarize common participant preference profiles, and the random effects capture additional individual-level preference heterogeneity with respect to three attribute domains: (a) privacy and confidentiality (testing venue, pre-test counseling, partner notification); (b) invasiveness and perceived accuracy (method for obtaining the sample for the HIV test); and (c) accessibility and value (testing availability, additional services provided). The Bayesian Information Criterion indicated the best model fit for a model with 8 preference classes, with class sizes ranging from 6% to 19% of participants. Substantial preference heterogeneity was observed, both between and within latent classes, with 12 of 16 attribute levels having positive and negative coefficients across classes, and all three random effects contributing significantly to participants' choices. The findings may help identify combinations of testing options that match the distribution of HIV testing preferences among high-risk populations; the methods may be used to systematically design heterogeneity-focused interventions using stated preference methods.

The demand for a COVID-19 vaccine in Kenya

The goal of achieving herd immunity to the coronavirus requires high vaccination acceptance levels on the part of the population. The objectives of this study were to: 1) Measure individuals' willingness to pay (WTP) for a COVID-19 vaccine in Kenya; 2) evaluate the effect of vaccine characteristics (duration of protection and efficacy) and individuals' socioeconomic variables on WTP, and 3) estimate the aggregate demand and economic value of a COVID-19 vaccine. The contingent valuation (CV) method was used as the basis for the analyses. Data for this study were obtained from a survey of 1,050 individuals in Kenya conducted from April 7 to April 15, 2020. The survey included CV questions using a double-bounded dichotomous choice format. Results reveal that most of the individuals in Kenya (at least 96%) were willing to accept a COVID-19 vaccine. Approximately 80% of individuals were willing to pay a positive amount. Conservative estimates of individuals' mean WTP for the vaccine range from USD 49.81 to USD 68.25 (depending on vaccine characteristics). Both vaccine duration of protection and efficacy were found to influence WTP (p < .10). The perceived probability of being hospitalized, age, gender, education, location and region of residence, and household income were also found to be associated with WTP for the vaccine (p < .10). In conclusion, the COVID-19 vaccine is highly valued and accepted by the Kenyan population; however, a high percent of the population is unwilling to pay for it or is only willing to pay a low price.

A National Survey to Assess the COVID-19 Vaccine-Related Conspiracy Beliefs, Acceptability, Preference, and Willingness to Pay among the General Population of Pakistan

The current study aims to assess the beliefs of the general public in Pakistan towards conspiracy theories, acceptance, willingness to pay, and preference for the COVID-19 vaccine. A cross-sectional study was conducted through an online self-administered questionnaire during January 2021. The Chi-square test or Fisher exact test was utilized for statistical data analysis. A total of 2158 respondents completed the questionnaire, among them 1192 (55.2%) were male with 23.87 (SD: ±6.23) years as mean age. The conspiracy beliefs circulating regarding the COVID-19 vaccine were believed by 9.3% to 28.4% of the study participants. Among them, 1040 (48.2%) agreed to vaccinate on its availability while 934 (43.3%) reported the Chinese vaccine as their preference. The conspiracy beliefs of the participants were significantly associated with acceptance of the COVID-19 vaccine. The existence of conspiracy beliefs and low vaccine acceptance among the general population is a serious threat to successful COVID-19 vaccination.

Public attitudes toward COVID-19 vaccination: The role of vaccine attributes, incentives, and misinformation

While efficacious vaccines have been developed to inoculate against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; also known as COVID-19), public vaccine hesitancy could still undermine efforts to combat the pandemic. Employing a survey of 1096 adult Americans recruited via the Lucid platform, we examined the relationships between vaccine attributes, proposed policy interventions such as financial incentives, and misinformation on public vaccination preferences. Higher degrees of vaccine efficacy significantly increased individuals' willingness to receive a COVID-19 vaccine, while a high incidence of minor side effects, a co-pay, and Emergency Use Authorization to fast-track the vaccine decreased willingness. The vaccine manufacturer had no influence on public willingness to vaccinate. We also found no evidence that belief in misinformation about COVID-19 treatments was positively associated with vaccine hesitancy. The findings have implications for public health strategies intending to increase levels of community vaccination.

Consumer willingness to pay for a hypothetical Chagas disease vaccine in Brazil: a cross-sectional study and the implications

Aim: Chagas disease is a serious public health problem, endemic in 21 countries in Latin America. A future vaccine can contribute to decreasing the number of cases and its complications. Methods: A cross-sectional study was conducted with residents of the northern region of Brazil, on the willingness to pay for a hypothetical vaccine against Chagas disease (effective protection of 80%). Results: We interviewed 619 individuals and seven were excluded from the analysis and the value of willingness to pay was US$23.77 (100.00 BRL). Conclusion: The Northern region of Brazil is one of the largest markets for this vaccine, due to its epidemiological relevance, so economic studies with this vaccine will be important to assist in the assessment of technologies.

Eliciting Preferences for HIV Prevention Technologies: A Systematic Review

Background

Many human immunodeficiency virus (HIV) prevention technologies (pre-exposure prophylaxis, microbicides, vaccines) are available or in development. Preference elicitation methods provide insight into client preferences that may be used to optimize products and services. Given increased utilization of such methods in HIV prevention, this article identifies and reviews these methods and synthesizes their application to HIV prevention technologies.

Methods

In May 2020, we systematically searched peer-reviewed literature in PubMed, CINAHL, and Web of Science for studies employing quantitative preference elicitation methods to measure preferences for HIV prevention technologies among populations of any age, sex, or location. Quality assessment used an existing checklist (PREFS) and a novel adaptation of the Newcastle–Ottawa Scale (PROSPERO #CRD42018087027).

Results

We screened 5022 titles and abstracts, reviewed 318 full texts, and included 84 studies. Common methods employed were discrete-choice experiment (33%), conjoint analysis (25%), and willingness-to-participate/try/accept (21%). Studies were conducted in 25 countries and had a mean of 768 participants (range = 26–7176), two-thirds of them male. Common HIV prevention technologies included pre-exposure prophylaxis (23%), voluntary testing and counseling (19%), HIV self-testing (17%), vaccines (15%), and topical microbicides (9%). Most attributes focused on product design (side effects, frequency), service design (provider type, location), acceptability or willingness to accept/pay; results are summarized in these categories, by prevention type. Mean quality-adapted Newcastle–Ottawa Scale score was 4.5/8 (standard deviation = 2.1) and mean PREFS scores was 3.47/5 (standard deviation = 0.81).

Conclusions

This review synthesizes extant literature on quantitative measurement of preferences for HIV prevention technologies. This can enable practitioners to improve prevention products and interventions, and ultimately reduce HIV incidence.

The demand for a COVID-19 vaccine in Ecuador

In Latin America, the country of Ecuador was one of the first and most severely affected by the COVID-19 pandemic. This study aimed to evaluate the demand for a COVID-19 vaccine in Ecuador by estimating individuals’ willingness to pay (WTP) for the vaccine, and by assessing the effect of vaccine attributes (duration of protection and efficacy) and individuals’ characteristics on this valuation. The sample used (N = 1,050) was obtained through an online survey conducted from April 2 to April 7, 2020. Two levels of vaccine efficacy (70% and 98%) and two levels of vaccine duration of protection (1 and 20 years) were considered. The willingness to pay estimates were obtained using a double-bounded dichotomous-choice contingent valuation format. Survey results show that a very large proportion of individuals (at least 97%) were willing to accept a COVID-19 vaccine, and at least 85% of individuals were willing to pay a positive amount for that vaccine. Conservative estimates of the average WTP values ranged from USD 147.61 to 196.65 and the median WTP from USD 76.9 to 102.5. Only the duration of protection was found to influence individuals’ WTP for the vaccine (p < 0.01). On average, respondents were willing to pay 30% more for a COVID-19 vaccine with 20 years of protection relative to the vaccine with 1 year of protection. Regression results show that WTP for the vaccine was associated with income, employment status, the perceived probability of needing hospitalization if contracting the virus causing COVID-19, and region of residence.

Using discrete choice experiments to design interventions for heterogeneous preferences: protocol for a pragmatic randomised controlled trial of a preference-informed, heterogeneity-focused, HIV testing offer for high-risk populations

INTRODUCTION

Approximately one million undiagnosed persons living with HIV in Southern and Eastern Africa need to test for HIV. Novel approaches are necessary to identify HIV testing options that match the heterogeneous testing preferences of high-risk populations. This pragmatic randomised controlled trial (PRCT) will evaluate the efficacy of a preference-informed, heterogeneity-focused HIV counselling and testing (HCT) offer, for improving rates of HIV testing in two high-risk populations.

METHODS AND ANALYSIS

The study will be conducted in Moshi, Tanzania. The PRCT will randomise 600 female barworkers and 600 male Kilimanjaro mountain porters across three study arms. All participants will receive an HIV testing offer comprised of four preference-informed testing options, including one 'common' option-comprising features that are commonly available in the area and, on average, most preferred among study participants-and three options that are specific to the study arm. Options will be identified using mixed logit and latent class analyses of data from a discrete choice experiment (DCE). Participants in Arm 1 will be offered the common option and three 'targeted' options that are predicted to be more preferred than the common option and combine features widely available in the study area. Participants in Arm 2 will be offered the common option and three 'enhanced' options, which also include HCT features that are not yet widely available in the study area. Participants in Arm 3, an active control arm, will be offered the common option and three predicted 'less preferred' options. The primary outcome will be uptake of HIV testing.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Duke University Health System IRB, the University of South Carolina IRB, the Ethics Review Committee at Kilimanjaro Christian Medical University College, Tanzania's National Institute for Medical Research, and the Tanzania Food & Drugs Authority (now Tanzania Medicines & Medical Devices Authority). Findings will be published in peer-reviewed journals. The use of rigorous DCE methods for the preference-based design and tailoring of interventions could lead to novel policy options and implementation science approaches.

TRIAL REGISTRATION NUMBER

NCT02714140.

PrEP Product Acceptability and Dual Process Decision-Making Among Men Who Have Sex with Men

PURPOSE OF REVIEW

Advances in short- and long-acting pre-exposure prophylaxis (PrEP) technologies have incentivized the need to understand how individuals make trade-offs and competing decisions regarding PrEP modalities. The purpose of this review was to examine how researchers have conceptualized and measured attributes that are either intuitive and emotional (System 1) or deliberative and cognitive (System 2) in conjoint analysis or discrete choice experiments focused on diverse PrEP technologies among men who have sex with men (MSM).

RECENT FINDINGS

Across the 9 studies meeting inclusion criteria, 5 included oral PrEP, 3 included topical rectal microbicides, 4 included PrEP injectables, and 1 study focused on an HIV prevention vaccine. Studies have not used uniform metrics, making comparisons difficult. Researchers measured attributes linked to System 2 processing (e.g., cost, efficacy), yet none examined System 1 processing. There is not one product or attribute preferable to all groups. Prevention products will need to be developed and promoted to reflect that diversity. Given that PrEP technologies have been solely informed by System 2 attributes, efforts to integrate System 1 attributes into ongoing and future PrEP choice experiments are pivotal to advance PrEP acceptability research and interventions to support their implementation.

Heterogeneous Patient Preferences for Modern Antiretroviral Therapy: Results of a Discrete Choice Experiment

OBJECTIVE

Limited data describe patient preferences for the growing number of antiretroviral therapies (ARTs). We quantified preferences for key characteristics of modern ART deemed relevant to shared decision making.

METHODS

A discrete choice experiment survey elicited preferences for ART characteristics, including dosing (frequency and number of pills), administration characteristics (pill size and meal requirement), most bothersome side effect (from diarrhea, sleep disturbance, headaches, dizziness/difficulty thinking, depression, or jaundice), and most bothersome long-term effect (from increased risk of heart attacks, bone fractures, renal dysfunction, hypercholesterolemia, or hyperglycemia). Between March and August 2017, the discrete choice experiment was fielded to 403 treatment-experienced persons living with human immunodeficiency virus (HIV), enrolled from 2 infectious diseases clinics in the southern United States and a national online panel. Participants completed 16 choice tasks, each comparing 3 treatment options. Preferences were analyzed using mixed and latent class logit models.

RESULTS

Most participants were male (68%) and older (interquartile range: 42-58 years), and had substantial treatment experience (interquartile range: 7-21 years). In mixed logit analyses, all attributes were associated with preferences. Side and long-term effects were most important, with evidence of substantial preference heterogeneity. Latent class analysis identified 5 preference classes. For classes 1 (40%), 2 (24%), and 3 (21%), side effects were most important, followed by long-term effects. For class 4 (10%), dosing was most important. Class 5 (4%) was largely indifferent to ART characteristics.

CONCLUSION

Overall, treatment-experienced persons living with HIV valued minimizing side effects and long-term toxicities over dosing and administration characteristics. Preferences varied widely, highlighting the need to elicit individual patient preferences in models of shared antiretroviral decision making.

A Conjoint Analysis of the Acceptability of Targeted Long-Acting Injectable Antiretroviral Therapy Among Persons Living with HIV in the U.S

With long-acting injectable antiretroviral therapy likely to be a treatment option for people living with HIV (PLWH), it is critical to assess its acceptability among potential end-users. Based on formative qualitative work and our own ongoing development of targeted long-acting products in nanosuspension formulations, we created eight hypothetical medication scenarios varying along six dichotomous attributes: administration location (home versus [vs.] clinic), dosing frequency (every 2 weeks vs. 1 week), injections per dose (one vs. two), injection pain (mild vs. moderate), injection site reaction (mild vs. moderate), and effectiveness (better vs. same as pills). PLWH from three outpatient care clinics in Seattle, WA and Riverside, CA rated acceptability (i.e., willingness to try each hypothetical medication) from 0 (very unlikely) to 100 (very likely). In conjoint analyses, we examined level and correlates of acceptability, the impact of each attribute on overall acceptability, and moderators of this effect. Participants (median age 52 years; 71% male, 34% White, 36% Black/African American, 20% Hispanic) rated acceptability of the 8 scenarios from 47.8 (standard deviation [SD] = 37.0) to 68.8 (SD = 34.1), with effectiveness (impact score = 7.3, SD = 18.7, p = 0.005) and dosing frequency (impact score = 5.7, SD = 19.6, p = 0.034) the only attributes with a significant impact on acceptability. There were no statistically significant differences in overall acceptability according to any participant socio-demographic or other characteristic; however, gender, education, employment status, and experience with and hatred/avoidance of injections moderated some effects. Overall acceptability for targeted long-acting antiretroviral treatment as proposed was modest, with superior effectiveness and lower dosing frequency most impactful on acceptability. Future acceptability research should continue to evaluate specific products in development with a full range of conjoint analytic and other techniques.

Stated-preference research in HIV: A scoping review

Discrete choice experiments (DCE), conjoint analysis (CA), and best-worst scaling (BWS) are quantitative techniques for estimating consumer preferences for products or services. These methods are increasingly used in healthcare research, but their applications within the field of HIV research have not yet been described. The objective of this scoping review was to systematically map the extent and nature of published DCE, CA, and BWS studies in the field of HIV and identify priority areas where these methods can be used in the future. Online databases were searched to identify published HIV-related DCE, CA and BWS studies in any country and year as the primary outcome. After screening 1,496 citations, 57 studies were identified that were conducted in 26 countries from 2000-2017. The frequency of published studies increased over time and covered HIV themes relating to prevention (n = 25), counselling and testing (n = 10), service delivery (n = 10), and antiretroviral therapy (n = 12). Most studies were DCEs (63%) followed by CA (37%) and BWS (4%). The median [IQR] sample size was 288 [138-496] participants, and 74% of studies used primary qualitative data to develop attributes. Only 30% of studies were conducted in sub-Saharan Africa where the burden of HIV is highest. Moreover, few studies surveyed key populations including men who have sex with men, transgender people, pregnant and postpartum women, adolescents, and people who inject drugs. These populations represent priorities for future stated-preference research. This scoping review can help researchers, policy makers, program implementers, and health economists to better understand the various applications of stated-preference research methods in the field of HIV.

Information sharing and willingness-to-pay for CBPP vaccine in rural Kenya

The study estimates cattle owners' willingness-to-pay (WTP) for Contagious Bovine Pleuropneumonia (CBPP) vaccine in Samburu county, Kenya. Of particular policy relevance, the study presents findings on WTP for i) improved access to vaccines and ii) timely access to disease-risk information. The mean price for a CBPP vaccine was estimated at KES 66 (USD 0.64). This price relates to a CBPP vaccine that requires a 1.8 h commute, cattle owners' receipt of timely information that the CBPP disease risk is low-moderate and the vaccine lowers the risk of either tail-drop or post-vaccine abortion. The conditional WTP for mean travel duration and high-risk information are similar at KES 53.9 and KES 51.5. The marginal effect on demand for a 1 h additional travel duration and provision of CBPP disease risk information was estimated as a 1.5 per cent reduction and 2.3 increase. The results of this study indicate that cattle owners value greater levels of knowledge concerning the changing risk profile of CBPP in their community and improved access to CBPP vaccination services. Enhanced engagement with cattle owners concerning CBPP would likely result in a greater utilisation of available CBPP vaccines, conditional on the perceived CBPP disease risk.

Discrete Choice Experiments in Health Economics: Past, Present and Future

OBJECTIVES

Discrete choice experiments (DCEs) are increasingly advocated as a way to quantify preferences for health. However, increasing support does not necessarily result in increasing quality. Although specific reviews have been conducted in certain contexts, there exists no recent description of the general state of the science of health-related DCEs. The aim of this paper was to update prior reviews (1990-2012), to identify all health-related DCEs and to provide a description of trends, current practice and future challenges.

METHODS

A systematic literature review was conducted to identify health-related empirical DCEs published between 2013 and 2017. The search strategy and data extraction replicated prior reviews to allow the reporting of trends, although additional extraction fields were incorporated.

RESULTS

Of the 7877 abstracts generated, 301 studies met the inclusion criteria and underwent data extraction. In general, the total number of DCEs per year continued to increase, with broader areas of application and increased geographic scope. Studies reported using more sophisticated designs (e.g. D-efficient) with associated software (e.g. Ngene). The trend towards using more sophisticated econometric models also continued. However, many studies presented sophisticated methods with insufficient detail. Qualitative research methods continued to be a popular approach for identifying attributes and levels.

CONCLUSIONS

The use of empirical DCEs in health economics continues to grow. However, inadequate reporting of methodological details inhibits quality assessment. This may reduce decision-makers' confidence in results and their ability to act on the findings. How and when to integrate health-related DCE outcomes into decision-making remains an important area for future research.

Consumer willingness to pay for a hypothetical Zika vaccine in Brazil and the implications

ABSTRACT  Background: Zika virus is a newly emerging infection, associated with increasingly large outbreaks especially in tropical countries such as Brazil. A future Zika vaccine can contribute to decreasing the number of cases and associated complications. Information about consumers' willingness to pay (WTP) for a hypothetical Zika vaccine can help price setting discussions in the future in Brazil, starting with the private market.

METHODS

A cross-sectional study conducted among residents of Minas Gerais, Brazil, regarding their WTP for a hypothetical Zika Vaccine. The mean effective protection was 80%, with the possibility of some local and systemic side- effects.

RESULTS

517 people were interviewed. However, 28 would not be vaccinated even if the vaccine was free. Most of the resultant interviewees (489) were female (58.2%), had completed high school (49.7%), were employed (71.2%), had private health insurance (52.7%), and did not have Zika (96.9%). The median individual maximum WTP for this hypothetical Zika vaccine (one dose) was US$31.34 (BRL100.00).

CONCLUSION

Such discussions regarding WTP can contribute to decision-making about prices once a Zika vaccine becomes available in Brazil alongside other ongoing programs to control the virus.

'Why would you promote something that is less percent safer than a condom?': Perspectives on partially effective HIV prevention technologies among key populations in South Africa

New biomedical prevention technologies (NPTs) for HIV, including oral Pre-Exposure Prophylaxis, and vaginal and rectal microbicides and HIV vaccines in development, may contribute substantially to controlling the HIV epidemic. However, their effectiveness is contingent on product acceptability and adherence. We explored perceptions and understanding of partially effective NPTs with key populations in South African townships. From October 2013 to February 2014, we conducted six focus groups and 18 individual interviews with Xhosa-speaking adolescents (n = 14), adult men who have sex with men (MSM) (n = 15), and adult heterosexual men (n = 9) and women (n = 10), and eight key informant (KI) interviews with healthcare workers. Interviews/focus groups were transcribed and reviewed using a thematic approach and framework analysis. Overall, participants and KIs indicated scepticism about NPTs that were not 100% efficacious. Some participants equated not being 100% effective with not being completely safe, and thus not appropriate for dissemination. KIs expressed concerns that promoting partially effective NPTs would encourage substitution of a more effective with a less effective method or encourage risk compensation. Educational and social marketing interventions that address the benefits and appropriate use of partially effective NPTs, including education and support tailored for frontline service providers, are needed to prepare for successful NPT implementation in South Africa.

A Systematic Review Comparing the Acceptability, Validity and Concordance of Discrete Choice Experiments and Best-Worst Scaling for Eliciting Preferences in Healthcare

OBJECTIVE

The aim of this study was to compare the acceptability, validity and concordance of discrete choice experiment (DCE) and best-worst scaling (BWS) stated preference approaches in health.

METHODS

A systematic search of EMBASE, Medline, AMED, PubMed, CINAHL, Cochrane Library and EconLit databases was undertaken in October to December 2016 without date restriction. Studies were included if they were published in English, presented empirical data related to the administration or findings of traditional format DCE and object-, profile- or multiprofile-case BWS, and were related to health. Study quality was assessed using the PREFS checklist.

RESULTS

Fourteen articles describing 12 studies were included, comparing DCE with profile-case BWS (9 studies), DCE and multiprofile-case BWS (1 study), and profile- and multiprofile-case BWS (2 studies). Although limited and inconsistent, the balance of evidence suggests that preferences derived from DCE and profile-case BWS may not be concordant, regardless of the decision context. Preferences estimated from DCE and multiprofile-case BWS may be concordant (single study). Profile- and multiprofile-case BWS appear more statistically efficient than DCE, but no evidence is available to suggest they have a greater response efficiency. Little evidence suggests superior validity for one format over another. Participant acceptability may favour DCE, which had a lower self-reported task difficulty and was preferred over profile-case BWS in a priority setting but not necessarily in other decision contexts.

CONCLUSION

DCE and profile-case BWS may be of equal validity but give different preference estimates regardless of the health context; thus, they may be measuring different constructs. Therefore, choice between methods is likely to be based on normative considerations related to coherence with theoretical frameworks and on pragmatic considerations related to ease of data collection.

Contexts of vulnerability and the acceptability of new biomedical HIV prevention technologies among key populations in South Africa: A qualitative study

BACKGROUND

New biomedical prevention technologies (NPTs) may contribute to substantially reducing incident HIV infections globally. We explored acceptability and preferences for NPTs among key and other vulnerable populations in two South African townships.

METHODS

We conducted six focus groups and 12 in-depth interviews with adolescents, and adult heterosexual men, women, and men who have sex with men (MSM) (n = 48), and eight in-depth interviews with key informant healthcare workers. The interview guide described pre-exposure prophylaxis (PrEP), vaginal rings, rectal microbicides and HIV vaccines, and explored acceptability and product preferences. Focus groups and in-depth interviews (45-80 minutes) were conducted in Xhosa, audiotaped, and transcribed and translated into English. Data were coded and reviewed using framework analysis with NVivo software.

RESULTS

Overall, initial enthusiasm and willingness to use NPTs evolved into concerns about how particular NPTs might affect or require alterations in one's everyday lifestyle and practices. Different product preferences and motivations emerged by population based on similarity to existing practices and contexts of vulnerability. Adult women and female adolescents preferred a vaginal ring and HIV vaccine, motivated by longer duration of protection to mitigate feared repercussions from male partners, including threats to their marriage and safety, and a context of ubiquitous rape. Male adolescents preferred an HIV vaccine, seen as protection in serodiscordant relationships and convenient in obviating the HIV stigma and cost involved in buying condoms. Adult men preferred PrEP, given familiarity with oral medications and mistrust of injections, seen as enabling serodiscordant couples to have a child. MSM preferred a rectal microbicide given familiarity with gel-based lubricants, with concerns about duration of protection in the context of unplanned consensual sex and rape.

CONCLUSIONS

Biomedical interventions to prevent HIV transmission, rather than obviating social-structural factors that produce vulnerability, may be limited by these same factors. Implementation of NPTs should engage local communities to understand real-world constraints and strategise to deliver effective, multi-level combination prevention.

Adolescent values for immunisation programs in Australia: A discrete choice experiment

Objectives

The importance of adolescent engagement in health decisions and public health programs such as immunisation is becoming increasingly recognised. Understanding adolescent preferences and further identifying barriers and facilitators for immunisation acceptance is critical to the success of adolescent immunisation programs. This study applied a discrete choice experiment (DCE) to assess vaccination preferences in adolescents.

Methods

This study was conducted as a cross-sectional, national online survey in Australian adolescents. The DCE survey evaluated adolescent vaccination preferences. Six attributes were assessed including disease severity, target for protection, price, location of vaccination provision, potential side effects and vaccine delivery method. A mixed logit model was used to analyse DCE data.

Results

This survey was conducted between December 2014 and January 2015. Of 800 adolescents aged 15 to 19 years, stronger preferences were observed overall for: vaccination in the case of a life threatening illness (p<0.001), lower price vaccinations (p<0.001), mild but common side effects (p = 0.004), delivery via a skin patch (p<0.001) and being administered by a family practitioner (p<0.001). Participants suggested that they and their families would be willing to pay AU$394.28 (95%CI: AU$348.40 to AU$446.92) more for a vaccine targeting a life threatening illness than a mild-moderate illness, AU$37.94 (95%CI: AU$19.22 to AU$57.39) more for being vaccinated at a family practitioner clinic than a council immunisation clinic, AU$23.01 (95%CI: AU$7.12 to AU$39.24) more for common but mild and resolving side effects compared to rare but serious side effects, and AU$51.80 (95%CI: AU$30.42 to AU$73.70) more for delivery via a skin patch than injection.

Conclusions

Consideration of adolescent preferences may result in improved acceptance of, engagement in and uptake of immunisation programs targeted for this age group.

Barriers and motivations to volunteers' participation in preventive vaccine trials: a systematic review

INTRODUCTION

The recruitment of volunteers in preventive vaccine trials (PVT) is a challenge, since vaccine hesitancy and debates on vaccines are combined to usual difficulties of enrollment in clinical trials. Areas covered: Current knowledge of the reasons leading to the volunteers' participation or non-participation in PVT mainly focuses on data from preventive HIV vaccine trials. A systematic PubMed search was conducted using PRISMA guidelines to identify articles or reviews that reported barriers and motivations to participation in PVT regardless of the targeted disease or population. Expert commentary: In view of the barriers and motivations reviewed here, improvements in recruitment could be made through a better explanation of the prevented disease, of the expected individual and collective benefit and of all ethical protective principles associated to the trials. Use of decision aids as well as patient and public involvement may improve given information and may enhance comprehension of participants and their participation in PVT. Further prospective and interventional studies are needed to analyze if these leads may improve acceptation level in PVT.

Using Best-Worst Scaling to Investigate Preferences in Health Care

INTRODUCTION

Best-worst scaling (BWS) is becoming increasingly popular to elicit preferences in health care. However, little is known about current practice and trends in the use of BWS in health care. This study aimed to identify, review and critically appraise BWS in health care, and to identify trends over time in key aspects of BWS.

METHODS

A systematic review was conducted, using Medline (via Pubmed) and EMBASE to identify all English-language BWS studies published up until April 2016. Using a predefined extraction form, two reviewers independently selected articles and critically appraised the study quality, using the Purpose, Respondents, Explanation, Findings, Significance (PREFS) checklist. Trends over time periods (≤2010, 2011, 2012, 2013, 2014 and 2015) were assessed further.

RESULTS

A total of 62 BWS studies were identified, of which 26 were BWS object case studies, 29 were BWS profile case studies and seven were BWS multi-profile case studies. About two thirds of the studies were performed in the last 2 years. Decreasing sample sizes and decreasing numbers of factors in BWS object case studies, as well as use of less complicated analytical methods, were observed in recent studies. The quality of the BWS studies was generally acceptable according to the PREFS checklist, except that most studies did not indicate whether the responders were similar to the non-responders.

CONCLUSION

Use of BWS object case and BWS profile case has drastically increased in health care, especially in the last 2 years. In contrast with previous discrete-choice experiment reviews, there is increasing use of less sophisticated analytical methods.

Acceptability and Preferences for Hypothetical Rectal Microbicides among a Community Sample of Young Men Who Have Sex with Men and Transgender Women in Thailand: A Discrete Choice Experiment

Rectal microbicides (RMs) may offer substantial benefits in expanding HIV prevention options for key populations. From April to August 2013, we conducted Tablet-Assisted Survey Interviewing, including a discrete choice experiment, with participants recruited from gay entertainment venues and community-based organizations in Chiang Mai and Pattaya, Thailand. Among 408 participants, 74.5 % were young men who have sex with men, 25.5 % transgender women, with mean age = 24.3 years. One-third (35.5 %) had ≤9th grade education; 63.4 % engaged in sex work. Overall, 83.4 % reported they would definitely use a RM, with more than 2-fold higher odds of choice of a RM with 99 versus 50 % efficacy, and significantly higher odds of choosing gel versus suppository, intermittent versus daily dosing, and prescription versus over-the-counter. Sex workers were significantly more likely to use a RM immediately upon availability, with greater tolerance for moderate efficacy and daily dosing. Engaging key populations in assessing RM preferences may support biomedical research and evidence-informed interventions to optimize the effectiveness of RMs in HIV prevention.

Use of an HIV-risk screening tool to identify optimal candidates for PrEP scale-up among men who have sex with men in Toronto, Canada: disconnect between objective and subjective HIV risk

INTRODUCTION

Identifying appropriate pre-exposure prophylaxis (PrEP) candidates is a challenge in planning for the safe and effective roll-out of this strategy. We explored the use of a validated HIV risk screening tool, HIV Incidence Risk Index for Men who have Sex with Men (HIRI-MSM), to identify "optimal" candidates among MSM testing at a busy sexual health clinic's community testing sites in Toronto, Canada.

METHODS

Between November 2014 and April 2015, we surveyed MSM undergoing anonymous HIV testing at community testing sites in Toronto, Canada, to quantify "optimal" candidates for scaling up PrEP roll-out, defined as being at high objective HIV risk (scoring ≥10 on the HIRI-MSM), perceiving oneself at moderate-to-high HIV risk and being willing to use PrEP. Cascades were constructed to identify barriers to broader PrEP uptake. The association between HIRI-MSM score and both willingness to use PrEP and perceived HIV risk were explored in separate multivariable logistic regression analyses.

RESULTS

Of 420 respondents, 64.4% were objectively at high risk, 52.5% were willing to use PrEP and 27.2% perceived themselves at moderate-to-high HIV risk. Only 16.4% were "optimal" candidates. Higher HIRI-MSM scores were positively associated with both willingness to use PrEP (aOR=1.7 per 10 score increase, 95%CI=1.3-2.2) and moderate-to-high perceived HIV risk (aOR=1.7 per 10 score increase, 95%CI=1.2-2.3). The proportion of men who were "optimal" candidates increased to 42.9% when the objective HIV risk cut-off was changed to top quartile of HIRI-MSM scores (≥26). In our full cascade, a very low proportion (5.3%) of MSM surveyed could potentially benefit from PrEP under current conditions. The greatest barrier in the cascade was low perception of HIV risk among high-risk men, but considerable numbers were also lost in downstream cascade steps. Of men at high objective HIV risk, 68.3% did not perceive themselves to be at moderate-to-high HIV risk, 23.6% were unaware of PrEP, 40.1% were not willing to use PrEP, 47.6% lacked a family physician with whom they felt comfortable discussing sexual health, and 31.6% had no means to cover the cost of PrEP.

CONCLUSIONS

A higher HIRI-MSM cut-off may be helpful for identifying candidates for PrEP scale-up. Improving engagement in the PrEP cascade will require interventions to simultaneously address multiple barriers.

Using discrete choice modeling to evaluate the preferences and willingness to pay for leptospirosis vaccine

Leptospirosis is highly endemic in the Philippines and a serious concern to public health. Local research on candidate vaccine is moving through the development pipeline. The availability of vaccines alone does not guarantee acceptance because individuals' vaccination choice decision is influenced by several factors. This study assessed how vaccine attributes and socio-demographic factors affect the acceptability of leptospirosis vaccine; and estimated individuals' willingness to pay for leptospirosis vaccine. A discrete choice experiment was conducted among leptospirosis and non-leptospirosis case respondents (n = 342) living in Metro Manila. Random Parameters Logit model was used to estimate the relative importance of vaccine attributes and socio-demographic variables on respondents' leptospirosis vaccination choice decision. The estimated model coefficients were used to derive implicit prices and willingness to pay for leptospirosis vaccine. Both case respondents preferred leptospirosis vaccine with 70-100% efficacy, mild to moderate risk of side-effects, given in a single shot, and at a lower price. Non-leptospirosis case respondents preferred a vaccine with 7 to 10 y of protection, while leptospirosis case respondents preferred a vaccine with 10 y protection. The probability of leptospirosis vaccination acceptance was affected by respondents' age, education, family size and income, proximity of home to rivers and sewers, and leptospirosis awareness level. Respondents' willingness to pay for leptospirosis vaccine (US$ 31.14-US$ 65.89) was higher than the Japanese retail price (US$ 21.60-US$ 24.00). Our findings indicated significant potential for introducing leptospirosis vaccine in the Philippine vaccine market. Delivery strategies to ensure equitable access to future leptospirosis vaccine are recommended.

Using conjoint analysis to determine the impact of product and user characteristics on acceptability of rectal microbicides for HIV prevention among Peruvian men who have sex with men

OBJECTIVES

Men who have sex with men (MSM) are in need of novel and acceptable HIV prevention interventions. In Peru, a Phase II clinical trial was recently completed evaluating rectally applied tenofovir gel among Peruvian MSM and transgender women. If deemed safe and acceptable, the product could move into efficacy testing, but acceptability data for similar products are needed now in order to prepare for future implementation. Peru is in need of expanded, national acceptability data among likely users.

METHODS

Using conjoint analysis of an online cross-sectional survey taken by 1008 Peruvian MSM and transgender women, we tested the acceptability of eight hypothetical rectal microbicide (RM) products comprising six, dual-value attributes. We also assessed the relationship of select product attributes with sample characteristics.

RESULTS

Highest acceptability was found for a RM that was 90% effective, used before and after sex, without side effects, costing approximately $0.30, had no prescription requirement and had a single-use applicator. Product effectiveness and presence of side effects were the factors most likely to drive RM acceptance and use. Education, sexual orientation, sexual role and concern for HIV infection were also related to aspects of RM acceptability.

CONCLUSION

RM acceptability was high, confirming the results of earlier, smaller studies and placing confidence in the acceptability of RMs. Analysis of the relationships with product attributes and sample characteristics underscore the need to consider the impact of factors such as sexual orientation, sexual role, level of education and concern for HIV acquisition on RM acceptability.

Stakeholder Engagement in HIV Cure Research: Lessons Learned from Other HIV Interventions and the Way Forward

Clinical and basic science advances have raised considerable hope for achieving an HIV cure by accelerating research. This research is dominated primarily by issues about the nature and design of current and future clinical trials. Stakeholder engagement for HIV cure remains in its early stages. Our analysis examines timing and mechanisms of historical stakeholder engagement in other HIV research areas for HIV-uninfected individuals [vaccine development and pre-exposure prophylaxis (PrEP)], and HIV-infected individuals (treatment as prevention, prevention of mother-to-child transmission, and treatment of acute HIV infection) and articulate a plan for HIV cure stakeholder engagement. The experience from HIV vaccine development shows that early engagement of stakeholders helped manage expectations, mitigating the failure of several vaccine trials, while paving the way for subsequent trials. The relatively late engagement of HIV stakeholders in PrEP research may partly explain some of the implementation challenges. The treatment-related stakeholder engagement was strong and community-led from the onset and helped translation from research to implementation. We outline five steps to initiate and sustain stakeholder engagement in HIV cure research and conclude that stakeholder engagement represents a key investment in which stakeholders mutually agree to share knowledge, benefits, and risk of failure. Effective stakeholder engagement prevents misconceptions. As HIV cure research advances from early trials involving subjects with generally favorable prognosis to studies involving greater risk and uncertainty, success may depend on early and deliberate engagement of stakeholders.

Acceptance of vaccinations in pandemic outbreaks: a discrete choice experiment

Background

Preventive measures are essential to limit the spread of new viruses; their uptake is key to their success. However, the vaccination uptake in pandemic outbreaks is often low. We aim to elicit how disease and vaccination characteristics determine preferences of the general public for new pandemic vaccinations.

Methods

In an internet-based discrete choice experiment (DCE) a representative sample of 536 participants (49% participation rate) from the Dutch population was asked for their preference for vaccination programs in hypothetical communicable disease outbreaks. We used scenarios based on two disease characteristics (susceptibility to and severity of the disease) and five vaccination program characteristics (effectiveness, safety, advice regarding vaccination, media attention, and out-of-pocket costs). The DCE design was based on a literature review, expert interviews and focus group discussions. A panel latent class logit model was used to estimate which trade-offs individuals were willing to make.

Results

All above mentioned characteristics proved to influence respondents’ preferences for vaccination. Preference heterogeneity was substantial. Females who stated that they were never in favor of vaccination made different trade-offs than males who stated that they were (possibly) willing to get vaccinated. As expected, respondents preferred and were willing to pay more for more effective vaccines, especially if the outbreak was more serious (€6–€39 for a 10% more effective vaccine). Changes in effectiveness, out-of-pocket costs and in the body that advises the vaccine all substantially influenced the predicted uptake.

Conclusions

We conclude that various disease and vaccination program characteristics influence respondents’ preferences for pandemic vaccination programs. Agencies responsible for preventive measures during pandemics can use the knowledge that out-of-pocket costs and the way advice is given affect vaccination uptake to improve their plans for future pandemic outbreaks. The preference heterogeneity shows that information regarding vaccination needs to be targeted differently depending on gender and willingness to get vaccinated.

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.

How much demand for New HIV prevention technologies can we really expect? Results from a discrete choice experiment in South Africa

Background

For the first time in the history of HIV, new bio-medical interventions have been shown to be effective in preventing HIV transmission. For these new HIV prevention technologies (NPTs) to have an impact on the epidemic, they must be widely used. This study uses a discrete choice experiment (DCE) to: understand the relative strength of women’s preferences for product characteristics, understand the implications for substitution away from male condoms, and inform realistic modelling of their potential impact and cost-effectiveness.

Methods

A DCE was conducted among 1017 women in urban South Africa. Women were presented with choices between potential women’s NPTs (microbicides, diaphragm, female condom) and ‘what I did last time’ (use or not use a condom) with different HIV and pregnancy prevention effectiveness’ and prices. Choice probabilities are estimated using the nested logit model and used to predict uptake.

Results

In this high HIV prevalence setting, HIV prevention effectiveness is the main driver of uptake followed by pregnancy prevention effectiveness. For example a microbicide with poor effectiveness would have niche appeal at just 11% predicted uptake, while a highly effective microbicide (95% effective against HIV and pregnancy) would have far wider appeal (56% predicted uptake). Though women who reported not using condoms were more likely to choose the NPTs, at current very high rates of male condom use in South Africa (60%), about half of microbicide uptake is projected to be among those currently not using condoms.

Conclusions

Women are very interested in NPTs, especially if highly effective in preventing HIV and pregnancy. Women in greatest need were also most likely to switch to the new products. Where products are not yet available for distribution, proxy data, such as that generated by DCEs, can bring realism to overly optimistic uptake scenarios found in many current impact models.