Selected Publications

PDRI Co-Director, Harsha Thirumurthy, coauthored an article inJAMA Network Open exploring how COVID-19 lockdowns influenced the economic well-being, food security, and sexual behavior of vulnerable populations in low- and middle-income countries. Findings from a survey in Kenya show lockdowns were associated with declines in employment, income, and numbers of sexual partners, suggesting negative economic impacts and temporarily reduced HIV risk in vulnerable populations.

HIV testing coverage in sub-Saharan Africa is lower among men than women. We investigated the impact of a peer-delivered U = U (undetectable equals untransmittable) message on men’s HIV testing uptake through a cluster randomized trial with individual mobile clinic days as a unit of randomisation.

On standard of care (SOC) days, peer promoters informed men about the availability of HIV testing at the mobile clinic. On intervention days, peer promoters delivered U = U messages. We used logistic regression adjusting for mobile clinic location, clustering by study day, to determine the percentage of invited men who tested for HIV at the mobile clinic.

Peer promoters delivered 1048 invitations over 12 days. In the SOC group, 68 (13%) of 544 men invited tested for HIV (3, 4.4% HIV-positive). In the U = U group, 112 (22%) of 504 men invited tested for HIV (7, 6.3% HIV-positive). Men in the U = U group had greater odds of testing for HIV (adjusted odds ratio = 1.89, 95% CI 1.21-2.95; p = 0.01).

Tailored, peer-delivered messages that explain the benefits of HIV treatment in reducing HIV transmission can increase men’s HIV testing uptake.

Frequent retesting for HIV among persons at increased risk of HIV infection is critical to early HIV diagnosis of persons and delivery of combination HIV prevention services. There are few evidence-based interventions for promoting frequent retesting for HIV. We sought to determine the effectiveness of financial incentives and deposit contracts in promoting quarterly HIV retesting among adults at increased risk of HIV.

HIV testing is a crucial first step to accessing HIV prevention and treatment services and to achieving the UNAIDS target of 95% of people living with HIV being aware of their status by 2030. Combined implementation of facility-based and community-based approaches has helped to achieve high levels of HIV testing coverage in many countries including those in sub-Saharan Africa.

Approaches such as index testing and self-testing help to reach individuals at higher risk of acquiring HIV, men, and those less likely to use health facilities or community-based services. However, as the proportion of people living with HIV who are aware of their HIV status has risen, the challenge of reaching those who remain undiagnosed or those who are at high risk of acquiring HIV has grown.

Demand generation and novel testing approaches will be necessary to reach undiagnosed people living with HIV and to promote frequent retesting among key and priority populations.

Background: HIV-positive women suffer a high burden of mental disorders due in part to gender-based violence (GBV). Comorbid depression and posttraumatic stress disorder (PTSD) are typical psychiatric consequences of GBV. Despite attention to the HIV-GBV syndemic, few HIV clinics offer formal mental healthcare. This problem is acute in sub-Saharan Africa, where the world’s majority of HIV-positive women live and prevalence of GBV is high.

Methods and findings: We conducted a randomized controlled trial at an HIV clinic in Kisumu, Kenya. GBV-affected HIV-positive women with both major depressive disorder (MDD) and PTSD were randomized to 12 sessions of interpersonal psychotherapy (IPT) plus treatment as usual (TAU) or Wait List+TAU. Nonspecialists were trained to deliver IPT inside the clinic. After 3 months, participants were reassessed, and those assigned to Wait List+TAU were given IPT. The primary outcomes were diagnosis of MDD and PTSD (Mini International Neuropsychiatric Interview) at 3 months.

Secondary outcomes included symptom measures of depression and PTSD, intimate partner violence (IPV), and disability. A total of 256 participants enrolled between May 2015 and July 2016. At baseline, the mean age of the women in this study was 37 years; 61% reported physical IPV in the past week; 91% reported 2 or more lifetime traumatic events and monthly income was 18USD. Multilevel mixed-effects logistic regression showed that participants randomized to IPT+TAU had lower odds of MDD (odds ratio [OR] 0.26, 95% CI [0.11 to 0.60], p = 0.002) and lower odds of PTSD (OR 0.35, [0.14 to 0.86], p = 0.02) than controls. IPT+TAU participants had lower odds of MDD-PTSD comorbidity than controls (OR 0.36, 95% CI [0.15 to 0.90], p = 0.03).

Linear mixed models were used to assess secondary outcomes: IPT+TAU participants had reduced disability (-6.9 [-12.2, -1.5], p = 0.01), and nonsignificantly reduced work absenteeism (-3.35 [-6.83, 0.14], p = 0.06); partnered IPT+TAU participants had a reduction of IPV (-2.79 [-5.42, -0.16], p = 0.04). Gains were maintained across 6-month follow-up. Treatment group differences were observed only at month 3, the time point at which the groups differed in IPT status (before cross over). Study limitations included 35% attrition inclusive of follow-up assessments, generalizability to populations not in HIV care, and data not collected on TAU resources accessed.

Conclusions: IPT for MDD and PTSD delivered by nonspecialists in the context of HIV care yielded significant improvements in HIV-positive women’s mental health, functioning, and GBV (IPV) exposure, compared to controls.

Introduction Interventions informed by behavioural economics, such as planning prompts, have the potential to increase HIV testing at minimal or no cost. Planning prompts have not been previously evaluated for HIV testing uptake. We conducted a randomised clinical trial to evaluate the effectiveness of low-cost planning prompts to promote HIV testing among men.

Methods We randomised adult men in rural Ugandan parishes to receive a calendar planning prompt that gave them the opportunity to make a plan to get tested for HIV at health campaigns held in their communities. Participants received either a calendar showing the dates when the community health campaign would be held (control group) or a calendar showing the dates and prompting them to select a date and time when they planned to attend (planning prompt group). Participants were not required to select a date and time or to share their selection with study staff. The primary outcome was HIV testing uptake at the community health campaign.

There are limited data characterizing HIV retesting among high-risk adults in sub-Saharan Africa. From October-December 2018, we distributed recruitment cards offering health evaluations with HIV testing at venues frequented by individuals at-risk of HIV infection in Southwest Uganda. Those who attended were asked about their HIV testing history and risk factors: having >1 sexual partner, an HIV+ partner, STIs, and/or transactional sex.

We defined “highest risk” as ≥3 risk factors and “frequent testing” as ≥3 tests within the past year. Of 1,777 cards distributed, 1,482 (83%) adults came to clinic: median age was 26(IQR: 22-31), 598 (40%) were men, and 334 (23%) were HIV+. Of 1,148 HIV-negative adults, 338 (29%) were highest risk and 205 (18%) were frequent testers. Frequent testing was similar in women (19%) and men (16%, p = 0.22). Among women, those at highest risk were more likely to report any testing (90% vs. 81%, p = 0.01) and frequent testing (25% vs. 18%, p = 0.06) than those at lower risk. Among men, any testing and frequent testing were similar between risk levels.

Among adults recruited from high-risk venues in peri-urban Uganda, HIV risk behaviors were commonly reported, yet frequent retesting remained low. Interventions to promote retesting are needed, particularly among men.

Voluntary physical distancing is essential for preventing the spread of COVID-19. Political partisanship may influence individuals’ responsiveness to recommendations from political leaders.

Daily mobility during March 2020 was measured using location information from a sample of mobile phones in 3,100 US counties across 49 states. Governors’ Twitter communications were used to determine the timing of messaging about COVID-19 prevention.

Regression analyses examined how political preferences influenced the association between governors’ COVID-19 communications and residents’ mobility patterns. Governors’ recommendations for residents to stay at home preceded stay-at-home orders and led to a significant reduction in mobility that was comparable to the effect of the orders themselves.

Effects were larger in Democratic than Republican-leaning counties, a pattern more pronounced under Republican governors. Democratic-leaning counties also responded more to recommendations from Republican than Democratic governors.

Political partisanship influences citizens’ decisions to voluntarily engage in physical distancing in response to communications by their governor.

Background: Bridging the efficacy-effectiveness gap in HIV prevention and treatment requires policies that account for human behavior.

Setting: Worldwide.

Methods: We conducted a narrative review of the literature on HIV in the field of economics, identified common themes within the literature, and identified lessons for implementation science.

Results: The reviewed studies illustrate how behaviors are shaped by perceived costs and benefits across a wide range of health and non-health domains, how structural constraints shape decision-making, how information interventions can still be effective in the epidemic’s fourth decade, and how lessons from behavioral economics can be used to improve intervention effectiveness.

Conclusion: Economics provides theoretical insights and empirical methods that can guide HIV implementation science.

Importance  Interventions to reduce men’s alcohol use and risky sexual behaviors are essential for reducing new HIV infections in high-prevalence settings in sub-Saharan Africa. Prize-linked savings accounts can motivate savings and may decrease expenditures on risky behaviors, but few studies have examined the HIV prevention potential of such savings interventions among men.

Objective  To evaluate the effect of prize-linked savings accounts on savings behavior and expenditures on alcohol, gambling, and transactional sex among men in Kenya.

Design, Setting, and Participants  Randomized clinical trial among communities in Siaya County, Kenya. Participants were men 21 years or older who owned a mobile phone were engaged in fishing or transportation sector work, and were willing to open an account with a local bank; they were screened for eligibility between September 3 and October 5, 2018.

Interventions  Eligible participants were offered savings accounts endowed with 1000 Kenya shillings (US $10) and randomized (1:1) to receive weekly lottery-based rewards contingent on growth in savings balance or to a control group that received standard interest.

Main Outcomes and Measures  The primary outcome was an indicator of whether a participant saved any money in the bank account (intent-to-treat analysis) during the study period. Secondary outcomes included the total amount saved in the bank account, the total amount saved in all sources, and expenditures on alcohol, gambling, and transactional sex.

Results  A total of 425 men were screened, 329 (77.4%) met eligibility criteria, 300 (70.6%) were enrolled (with 152 randomized to the intervention group and 148 to the control group), and 270 of 300 (90.0%) opened bank accounts. Participants’ mean age was 33.7 years (interquartile range, 13.5 years), 84.3% (253 of 300) were married, and the mean weekly earnings were US $30 (interquartile range, US $23). During a mean (SD) follow-up of 9 (2) weeks, 37.3% (50 of 134) in the intervention group saved money in a bank account vs 27.2% (37 of 136) in the control group, although the difference was not statistically significant (odds ratio, 1.62; 95% CI, 0.96-2.74). The intervention group had higher growth in bank savings balances (US $10.26; 95% CI, US $5.00-US $58.20 vs US $4.87; 95% CI, US $0.67-US $9.00) and higher total savings from all sources (US $201; 95% CI, US $133-US $269 vs US $145; 95% CI, US $88-US $202), but neither difference was statistically significant. The intervention did not have a significant effect on alcohol, gambling, and transactional sex expenditures.

Conclusions and Relevance  Prize-linked savings accounts modestly increased savings among high-risk men in Kenya over a 9-week period, but the difference compared with standard-interest savings accounts was not significant. Testing of more powerful savings products is needed to assess whether such savings-led interventions can reduce men’s expenditures on alcohol, gambling, and transactional sex.

Greater awareness of HIV status and more frequent testing in high-risk populations are essential for realizing the promise of treatment as prevention and achieving the 90-90-90 targets of the Joint United Nations Programme on HIV/AIDS (that by 2020, 90% of people living with HIV will know their HIV status, 90% of people with diagnosed HIV will be on antiretroviral therapy [ART], and 90% of people receiving ART will be virally suppressed).¹ Yet in sub-Saharan Africa, nearly 20% of people living with HIV were unaware of their status in 2017.² Despite the scale-up of a clinic- and community-based models for providing HIV testing services, testing coverage remains suboptimal, particularly among men and other key populations.³ To close the testing gap and advance HIV prevention objectives, innovative approaches are needed to increase the uptake of HIV testing in sub-Saharan Africa.

A self-administered test for HIV allows individuals to collect their own sample and to perform a simple, rapid HIV antibody test in the absence of a health care practitioner.⁴ Several oral fluid-based or blood-based HIV tests have received prequalification from the World Health Organization and showed high sensitivity and specificity among lay users.⁴ Existing research shows high interest in and acceptability of HIV self-testing across a wide range of populations.^5–12 After the 2016 World Health Organization guidelines that recommended large-scale implementation of HIV self-testing, self-tests are becoming more widely available in governmental health facilities and retail outlets in several countries in sub-Saharan Africa with high HIV prevalence.⁴

Donor agencies and governments have heavily subsidized HIV self-tests for distribution in some countries, and private sector availability is emerging in parallel.¹³ However, the cost of self-tests and the price for consumers represent important obstacles to large-scale implementation of HIV self-testing. As countries seek to scale up HIV self-testing for priority populations, little evidence exists on the effect of alternative pricing and marketing strategies on self-testing demand. A growing body of evidence from low-income countries shows that demand for prevention technologies, such as antimalarial bed nets and water filtration solutions, is highly price sensitive.^14–19 Knowing the self-testing demand at various prices in the general population and key subgroups is important for setting appropriate subsidy levels for these self-tests and for understanding the demand for HIV prevention technologies in general. Moreover, with HIV self-testing, information is limited about the optimal distribution approaches for reaching untested individuals and messaging strategies for promoting the adoption of such new technologies. Estimating how demand is affected not only by prices but also by various distribution approaches and types of information provided to consumers can further inform HIV self-testing scale-up efforts.

We conducted a large community-based randomized clinical trial to examine the optimal pricing policies and distribution strategies for HIV self-testing in Zimbabwe.

If intrinsic motivations alone were enough to influence health behaviors, individuals would not smoke, all drivers would wear seat belts, and patients with chronic conditions would take their medications. Yet approximately half of patients prescribed single-drug therapy for hypertension discontinue their medications within a year,¹ even though presumably they want to avoid strokes and hopefully know that taking their medication is one way to reduce health risks.

To supplement the intrinsic motivations apparently insufficient to the task, economists and others have long proposed extrinsic motivations in the form of financial rewards. These rewards offer the added benefit of being immediate rather than the typically delayed intrinsic rewards of better health sometime in the future. Studies in varied health domains have revealed that financial incentives work well.

For example, a 2015 systematic review determined that to reduce smoking during pregnancy, financial or material incentives were more effective than other medical or behavioral strategies.² The use of incentives is also widespread. In 2018, 86% of US employers offered some financial incentives for healthy behavior,³ and in lower-income countries, conditional cash transfer programs rewarded utilization of preventive services.

Objective:

To assess the comparative effectiveness of alternative incentive-based interventions to promote HIV testing among men.

Design:

Randomized clinical trial.

Methods:

We enumerated four Ugandan parishes and enrolled men at least 18 years. Participants were randomized to six groups that received incentives of varying types and amount for HIV testing at a 13-day community health campaign. Incentive types were: gain-framed (control): participants were told they would receive a prize for testing; loss-framed: participants were told they had won a prize, shown several prizes, asked to select one, then told they would lose the prize if they did not test; lotteries: those who tested had a chance to win larger prizes. Each incentive type had a low and high amount (∼US$1 and US$5/participant). The primary outcome was HIV-testing uptake at the community health campaign.

Results:

Of 2532 participants, 1924 (76%) tested for HIV; 7.6% of those tested were HIV-positive. There was no significant difference in testing uptake in the two lottery groups (78%; P = 0.076) or two loss-framed groups (77%; P = 0.235) vs. two gain-framed groups (74%). Across incentive types, testing did not differ significantly in high-cost (76%) vs. low-cost (75%; P = 0.416) groups. Within low-cost groups, testing uptake was significantly higher in the lottery (80%) vs. gain-framed (72%; P = 0.009) group.

Conclusion:

Overall, neither offering incentives via lotteries nor framing incentives as losses resulted in significant increases in HIV testing compared with standard gain-framed incentives. However, when offering low-cost incentives to promote HIV testing, providing lottery-based rewards may be a better strategy than gain-framed incentive