Q&A: First-hand perspectives as a member of the BMC Medicine Editorial Board scheme: an interview with Matthew Quaife and Shuai Li.

Funder: Victorian Cancer AgencyFunder: Bill and Melinda Gates Foundatio

Data for: Partnership preferences, economic drivers, and health consequences of Gambian men's interactions with foreign tourists

The study investigated partnership preferences, economic drivers, and health consequences of Gambian men's interactions with foreign tourists. Research outputs include a topic guide for in-depth interviews; informed consent forms for face-to-face interviews, focus group discussion and survey; and a survey dataset

What are.. Discrete Choice Experiments

Mr Mathew Quaife makes a presentation on economics and choices.He emphasizes that choices must be made amidst scarce resource

Modelling the effect of market forces on the impact of introducing human immunodeficiency virus pre‐exposure prophylaxis among female sex workers

Pre-exposure prophylaxis (PrEP) to prevent human immunodeficiency virus (HIV) enables female sex workers (FSWs) to protect themselves from HIV without relying on clients using condoms. Yet, because PrEP reduces HIV risk, financial incentives to not use condoms may lead to risk compensation: reductions in condom use and/or increases in commercial sex, and may reduce the price of unprotected sex. In this analysis, we integrate market forces into a dynamic HIV transmission model to assess how risk compensation could change the impact of PrEP among FSWs and clients. We parameterise how sexual behavior may change with PrEP use among FSWs using stated preference data combined with economic theory. Our projections suggest the impact of PrEP is sensitive to risk compensatory behaviors driven by changes in the economics of sex work. Condom substitution could reduce the impact of PrEP on HIV incidence by 55%, while increases in the frequency of commercial sex to counter decreases in the price charged for unprotected sex among PrEP users could entirely mitigate the impact of PrEP. Accounting for competition between PrEP users and nonusers exacerbates this further. Alternative scenarios where increases in unprotected sex among PrEP users are balanced by decreases in non-PrEP users have the opposite effect, resulting in PrEP having much greater impact. Intervention studies need to determine how HIV prevention products may change the economics of sex work and provision of unprotected sex to enable a better understanding of their impact

HIV prevention is not all about HIV - using a discrete choice experiment among women to model how the uptake and effectiveness of HIV prevention products may also rely on pregnancy and STI protection.

INTRODUCTION: In sub-Saharan Africa, considerable HIV-burden exists among women. Anti-retroviral (ARV) based prevention products could decrease this burden, and their uptake could be increased if they also protect against pregnancy and sexually transmitted infections (STI). METHODS: A discrete choice experiment (DCE) was undertaken in South Africa (2015) through a household survey of adult females (n = 158) and adolescent girls (n = 204) who self-reported HIV-negative status. The DCE was used to project the uptake (percentage using product) of oral pre-exposure prophylaxis (PrEP), vaginal rings, and injectable long-lasting ARV agents among these women, and how uptake could depend on whether these products protect against pregnancy or STI acquisition. Uptake estimates were used to model how each product could decrease a women's HIV acquisition risk. RESULTS: In adolescent women, there will be limited uptake ( 14% of women will remain unprotected and > 31% of the baseline acquisition risk will remain. CONCLUSIONS: Incorporating multiple prevention components into new ARV-based prevention products may increase their uptake and impact among women

Modelling the effect of market forces on the impact of introducing HIV pre-exposure prophylaxis among female sex workers

HIV pre-exposure prophylaxis (PrEP) enables female sex workers (FSWs) to protect themselves from HIV without relying on clients using condoms. Yet, because PrEP reduces HIV risk, financial incentives to not use condoms may lead to risk compensation: reductions in condom use and/or increases in commercial sex, and may reduce the price of unprotected sex. In this analysis, we integrate market forces into a dynamic HIV transmission model to assess how risk compensation could change the impact of PrEP among FSWs and clients. We parameterise how sexual behaviour may change with PrEP use among FSWs using stated preference data combined with economic theory. Our projections suggest the impact of PrEP is sensitive to risk compensatory behaviours driven by changes in the economics of sex work. Condom substitution could reduce the impact of PrEP on HIV incidence by 55%, while increases in the frequency of commercial sex to counter decreases in the price charged for unprotected sex among PrEP users could entirely mitigate the impact of PrEP. Accounting for competition between PrEP users and non-users exacerbates this further. Alternative scenarios where increases in unprotected sex among PrEP users are balanced by decreases in non-PrEP users have the opposite effect, resulting in PrEP having much greater impact. Intervention studies need to determine how HIV prevention products may change the economics of sex work and provision of unprotected sex to enable a better understanding of their impact

Using Choice Experiments to Improve Equity in Access to Socially Marketed HIV Prevention Products

Designing strategies to introduce new HIV prevention technologies requires balancing equitable access with sustainable distribution, particularly in resource constrained settings with high HIV prevalence. This paper explores how knowledge of preference heterogeneity can guide the equitable targeting of HIV prevention products using differentiated advertising and product placement to balance increased access with sustainability. A discrete choice experiment elicited 1016 women's preferences for distribution of HIV prevention products in South Africa. Qualitative research guided the experimental design which considered distribution outlet, collection method, advertising message, and price. A range of choice models, including random parameters logit, latent class and latent class random parameters logit models, were compared for fit. A latent class model showed the best fit and distinguished two classes of women: Class 1 were significantly more likely to be cohabiting and unemployed, who preferred products advertised for HIV prevention distributed through clinics and were highly price sensitive. Class 2 significantly preferred distribution through pharmacies and advertising around women's empowerment, while price was not a key factor. This analysis suggests that equity in access to new products could be advanced through exploiting preference heterogeneity between groups. The identified groups can be then used to design social marketing differentiated distribution strategies. Distributing free products promoted for HIV prevention could discourage ‘leakage’ of highly subsidised products to women with some capacity to pay, while priced products marketed for women's empowerment through pharmacies could encourage cost recovery with minimal reductions in coverage among employed women

Preferences for ARV-based HIV prevention methods among men and women, adolescent girls and female sex workers in Gauteng Province, South Africa: a protocol for a discrete choice experiment.

INTRODUCTION: For the past few decades, condoms have been the main method of HIV prevention. Recent advances in antiretroviral (ARV)-based prevention products have substantially changed the prevention landscape, yet little is known about how popular these products will be among potential users, or whether new methods might be used in conjunction with, or instead of, condoms. This study will use a discrete choice experiment (DCE) to (1) explore potential users' preferences regarding HIV prevention products, (2) quantify the importance of product attributes and (3) predict the uptake of products to inform estimates of their potential impact on the HIV epidemic in South Africa. We consider preferences for oral pre-exposure prophylaxis; a vaginal microbicide gel; a long-acting vaginal ring; a SILCS diaphragm used in concert with gel; and a long-acting ARV-based injectable. METHODS AND ANALYSIS: This study will gather data from 4 populations: 200 women, 200 men, 200 adolescent girls (aged 16-17 years) and 200 female sex workers. The DCE attributes and design will be developed through a literature review, supplemented by a thematic analysis of qualitative focus group discussions. Extensive piloting will be carried out in each population through semistructured interviews. The final survey will be conducted using computer tablets via a household sample (for women, men and adolescents) and respondent-driven sampling (for female sex workers), and DCE data analysed using a range of multinomial logit models. ETHICS AND DISSEMINATION: This study has been approved by the University of the Witwatersrand Human Research Ethics Committee and the Research Ethics Committee at the London School of Hygiene and Tropical Medicine. Findings will be presented to international conferences and peer-reviewed journals. Meetings will be held with opinion leaders in South Africa, while results will be disseminated to participants in Ekurhuleni through a public meeting or newsletter