"Sisters, Mothers, Daughters and Aunties": HIV vaccine acceptability among African, Caribbean and other Black women in Toronto

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.

Broken Promises: Racism and Access to Medicines in Canada

BACKGROUND

Discriminatory policies, attitudes, and practices have had deleterious impacts on the health of Black, Indigenous, and other racialized groups. The aim of this study was to investigate racism as barrier to access to medicines in Canada. The study investigated the characteristics of structural racism and implicit biases that affect medicines access.

METHODS

A scoping review using the STARLITE literature retrieval approach and analysis of census tract data in Toronto, Ontario, Canada, were undertaken. Government documents, peer-reviewed articles from public policy, health, pharmacy, social sciences, and gray literature were reviewed.

RESULTS

Structural racism that created barriers to access to medicines and vaccines was identified in policy, law, resource allocation, and jurisdictional governance. Institutional barriers included health care providers' implicit biases about racialized groups, immigration status, and language. Pharmacy deserts in racialized communities represented a geographic barrier to access.

CONCLUSION

Racism corrupts and impedes equitable allocation and access to medicine in Canada. Redefining racism as a form of corruption would obligate societal institutions to investigate and address racism within the context of the law as opposed to normative policy. Public health policy, health systems, and governance reform would remove identified barriers to medicines, vaccines, and pharmaceutical services by racialized groups.

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.

Using surrogate vaccines to assess feasibility and acceptability of future HIV vaccine trials in men: a randomised trial in inner-city Johannesburg, South Africa

BACKGROUND

Developing an effective HIV vaccine is the overriding priority for HIV prevention research. Enrolling and maintaining cohorts of men into HIV vaccine efficacy trials is a necessary prerequisite for the development and licensure of a safe and efficacious vaccine.

METHODS

One hundred-fifty consenting HIV-negative men were enrolled into a pilot 1:1 randomised controlled trial of immediate vaccination with a three-dose hepatitis B vaccine compared to deferred vaccination (at 12 months) to investigate feasibility and acceptability of a future HIV vaccine trial in this population. Adverse events, changes in risk behaviour, acceptability of trial procedures and motivations for participation in future trials were assessed.

RESULTS

Men were a median 25 years old (inter-quartile range = 23-29), 53% were employed, 90% secondary school educated and 67% uncircumcised. Of the 900 scheduled study visits, 90% were completed in the immediate vaccination arm (405/450) and 88% (396/450) in the delayed arm (P = 0.338). Acceptability of trial procedures and services was very high overall. However, only 65% of the deferred group strongly liked being randomised compared to 90% in the immediate group (P = 0.001). Informed consent processes were viewed favourably by 92% of the delayed and 82% of the immediate group (P = 0.080). Good quality health services, especially if provided by a male nurse, were rated highly. Even though almost all participants had some concern about the safety of a future HIV vaccine (98%), the majority were willing to participate in a future trial. Future trial participation would be motivated mainly by the potential for accessing an effective vaccine (81%) and altruism (75%), rather than by reimbursement incentives (2%).

CONCLUSIONS

Recruitment and retention of men into vaccine trials is feasible and acceptable in our setting. Findings from this surrogate vaccine trial show a high willingness to participate in future HIV vaccine trials. While access to potentially effective vaccines is important, quality health services are an equally compelling incentive for enrolment.

Quantifying population preferences around vaccination against severe but rare diseases: A conjoint analysis among French university students, 2016

BACKGROUND

Several concepts are available to explain vaccine decision making by individual and inter-individual factors, including risk perception, social conformism and altruism. However, only a few studies have quantified the weight of these determinants in vaccine acceptance. Using a conjoint analysis tool, we aimed at eliciting preferences in a student population regarding vaccination against a rare, severe and rapidly evolving hypothetical disease, similar to meningococcal serogroup C meningitis or measles.

METHODS

During March-May 2016, we conducted an emailing survey among university students aged 18-24years (N=775) in Rennes, France. Participants were asked to decide for or against immediate vaccination in 24 hypothetical scenarios, containing various levels of four attributes: epidemic situation, adverse events, information on vaccination coverage, and potential for indirect protection. Data were analysed using random effect estimator logit models.

RESULTS

Participants accepted on average 52% of scenarios and all attributes significantly impacted vaccination acceptance. The highest positive effects were seen with an epidemic situation (OR 3.81, 95%-CI 3.46-4.19), 90% coverage in the community (3.64, 3.15-4.20) and potential for disease elimination from the community (2.87, 2.53-3.26). Information on "insufficient coverage" was dissuasive (vs. none of friends vaccinated: 0.65, 0.56-0.75). Controversy had a significantly greater negative effect than a confirmed risk of severe adverse events (OR 0.05 vs. 0.22). In models including participant characteristics, preference weights were unchanged, while trust in health authorities and vaccination perceptions strongly influenced acceptance themselves. The greatest significant variation of preference weights between subgroups was observed with controversy among students using alternative medicine daily (OR 0.28) and among students relying on scientific vaccine information (OR 0.02).

CONCLUSIONS

Among young adults, potential for indirect protection and factual information on coverage in the community and potential side effects positively impact theoretical vaccine acceptance. Conjoint analyses should be conducted to understand vaccine hesitancy in specific vaccination programs.

Drivers of Vaginal Drug Delivery System Acceptability from Internet-Based Conjoint Analysis

Vaginal microbicides potentially empower women to protect themselves from HIV and other sexually transmitted infections (STIs), especially when culture, religion, or social status may prevent them from negotiating condom use. The open literature contains minimal information on factors that drive user acceptability of women's health products or vaginal drug delivery systems. By understanding what women find to be most important with regard to sensory properties and product functionality, developers can iteratively formulate a more desirable product. Conjoint analysis is a technique widely used in market research to determine what combination of elements influence a consumer's willingness to try or use a product. We applied conjoint analysis here to better understand what sexually-active woman want in a microbicide, toward our goal of formulating a product that is highly acceptable to women. Both sensory and non-sensory attributes were tested, including shape, color, wait time, partner awareness, messiness/leakage, duration of protection, and functionality. Heterosexually active women between 18 and 35 years of age in the United States (n = 302) completed an anonymous online conjoint survey using IdeaMap software. Attributes (product elements) were systematically presented in various combinations; women rated these combinations of a 9-point willingness-to-try scale. By coupling systematic combinations and regression modeling, we can estimate the unique appeal of each element. In this population, a multifunctional product (i.e., broad spectrum STI protection, coupled with conception) is far more desirable than a microbicide targeted solely for HIV protection; we also found partner awareness and leakage are potentially strong barriers to use.

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.

Determinants of intravaginal practices among HIV-infected women in Zambia using conjoint analysis

Intravaginal practices (IVPs) are associated with an increased risk of bacterial vaginosis and may play a role in HIV transmission. The objective of this study was to identify the importance of factors underlying the decision to engage in IVP using conjoint analysis; a novel statistical technique used to quantify health-related decisions. This study was a cross-sectional study. HIV-infected women in Zambia completed audio computer-administered self-interview questionnaires assessing demographic, risk factors and IVPs. Reasons for engaging in IVPs were explored using conjoint questionnaires. Conjoint analysis was used to identify the relative importance of factors for engaging in IVPs. Results of the conjoint analysis demonstrated that hygiene was the most important reason for engaging in IVPs (mean importance score = 61, SD = 24.3) followed by partner's preference (mean importance score = 20, SD = 14.4) and health (mean importance score = 17, SD = 13.5). When making the decision to engage in IVPs, women rank the importance of hygiene, partner preference and health differently, according to their personal characteristics. The use of conjoint analysis to define the characteristics of women more likely to engage in specific practices should be used to develop tailored rather than standardised IVP interventions, and such interventions should be incorporated into clinical practice and women's health programmes.