The heterogeneous effects of HIV testing

Healthy, nudged, and wise: Experimental evidence on the role of information salience in reducing tobacco intake

We evaluate the performance of two behavioral interventions aimed at reducing tobacco consumption in an ultra-poor rural region of Bangladesh, where conventional methods like taxes and warning labels are infeasible. The first intervention asked participants to daily log their tobacco consumption expenditure. The second intervention placed two graphic posters with warnings about the harmful effects of tobacco consumption on tobacco users and their children in the sleeping quarters of the participating households. While both interventions reduced household tobacco consumption expenditure, male participants who logged their expenditure substituted cigarettes with cheaper smokeless tobacco. The reduction in tobacco intake is larger among males with a non-tobacco consuming spouse. Exploratory analysis reveals that risk-averse males who spent relatively more on tobacco responded more to the logbook intervention. More educated, patient males with children below age five responded better to the poster intervention. The findings suggest that in countries with multi-tiered tobacco excise tax structures, which incentivize downward substitution, extending complementary demand-side policies that worked elsewhere to the rural poor might be unwise. Instead, policies may leverage something as universal as parental concern for their children's health to promote better health decision-making.

Lau K, Miraldo M, Hauck K. Bandwagoning, free-riding and heterogeneity in influenza vaccine decisions: An online experiment

'Nudge'-based social norms messages conveying high population influenza vaccination coverage levels can encourage vaccination due to bandwagoning effects but also discourage vaccination due to free-riding effects on low risk of infection, making their impact on vaccination uptake ambiguous. We develop a theoretical framework to capture heterogeneity around vaccination behaviors, and empirically measure the causal effects of different messages about vaccination coverage rates on four self-reported and behavioral vaccination intention measures. In an online experiment, N = 1365 UK adults are randomly assigned to one of seven treatment groups with different messages about their social environment's coverage rate (varied between 10% and 95%), or a control group with no message. We find that treated groups have significantly greater vaccination intention than the control. Treatment effects increase with the coverage rate up to a 75% level, consistent with a bandwagoning effect. For coverage rates above 75%, the treatment effects, albeit still positive, stop increasing and remain flat (or even decline). Our results suggest that, at higher coverage rates, free-riding behavior may partially crowd out bandwagoning effects of coverage rate messages. We also find significant heterogeneity of these effects depending on the individual perceptions of risks of infection and of the coverage rates.

Does Venue of HIV Testing and Results Disclosure in the Context of a Research Study Affect Adolescent Health and Behavior? Results from a Study in Western Kenya

Ethical concerns about risks to minor adolescents participating in HIV prevention research is a barrier to their inclusion. One concern is whether HIV testing and results disclosure venue affects the health and behavior of adolescent participants. We assessed for differential effects on quality of life (QOL), depressive symptoms, and sexual behavior due to (1) testing venue (home or health facility) and (2) test result (HIV-positive, HIV-negative, indeterminate). We collected data at three timepoints (baseline, 2-month follow-up, 12-month follow-up) from 113 Kenyan adolescents aged 15-19 (51% female). We analyzed the data using linear mixed effects models for the QOL and depressive symptoms outcomes and a logistic model for the sexual behavior outcome. Results showed a small mental health benefit for adolescents tested for HIV at a health facility compared with home. There was little evidence that testing venue influenced sexual behavior or that test results moderated the effects of HIV testing across all outcomes. The decision to conduct HIV testing at home or a health facility may not be very consequential for adolescents' health and behavior. Findings underscore the need to critically examine assumptions about adolescent vulnerability to better promote responsible conduct of HIV prevention research with youth in sub-Saharan Africa.

Characteristics and Sexual Risk Behavior of Men Who Never Tested for HIV in Zambia

Compared with women and girls, proportionately fewer men and boys in sub-Saharan Africa receive HIV testing, treatment, and other services. This study determined factors associated with never testing for HIV and examined never testing as a predictor of sexual risk behavior among men in Zambia. The sample included 2,609 men aged 15 to 24 from the 2018 Zambia Demographic and Health Survey. Logistic regression results revealed that compared with men who ever tested for HIV, men who never tested were more likely to be younger, have less education, have no children, be unemployed, and belong to the low wealth bracket. They also had a higher likelihood of not using a condom at last sex but were less likely to have more than five lifetime sexual partners. HIV prevention programs can use sociodemographic characteristics to identify those who have a lower likelihood of testing for HIV. Prevention programs can use sociodemographic characteristics to develop profiles of those who may especially need to be targeted by initiatives to promote HIV testing. Awareness does not always engender behavior change; therefore, in addition to knowledge of HIV status, risk reduction should also be emphasized.

Adverse Selection in the Marriage Market: HIV Testing and Marriage in Rural Malawi

Asymmetric information in the marriage market may cause adverse selection and delay marriage if partner quality is revealed over time. Sexual safety is an important but hidden partner attribute, especially in areas where HIV is endemic. A model of positive assortative matching with both observable (attractiveness) and hidden (sexual safety) attributes predicts that removing the asymmetric information about sexual safety accelerates marriage and pregnancy for safe respondents, and more so if they are also attractive. Frequent HIV testing may enable safe people to signal and screen. Consistent with these predictions, we show that a high-frequency, "opt-out" HIV testing intervention changed beliefs about partner's safety and accelerated marriage and pregnancy, increasing the probabilities of marriage and pregnancy by 26 and 27 percent for baseline-unmarried women over 28 months. Estimates are larger for safe and attractive respondents. Conversely, a single-test intervention lacks these effects, consistent with other HIV testing evaluations in the literature. Our findings suggest that an endogenous response to HIV risk may explain why the HIV/AIDS epidemic has coincided with systematic marriage and pregnancy delays.

Sexual behaviour change following HIV testing services: a systematic review and meta-analysis

INTRODUCTION

Learning one's HIV status through HIV testing services (HTS) is an essential step toward accessing treatment and linking to preventive services for those at high HIV risk. HTS may impact subsequent sexual behaviour, but the degree to which this varies by population or is true in the setting of contemporary HIV prevention activities is largely unknown. As part of the 2019 World Health Organization Consolidated Guidelines on HTS, we undertook a systematic review and meta-analysis to determine the effect of HTS on sexual behaviour.

METHODS

We searched nine electronic databases for studies published between July 2010 and December 2019. We included studies that reported on at least one outcome (condom use [defined as the frequency of condom use or condom-protected sex], number of sex partners, HIV incidence, STI incidence/prevalence). We included studies that prospectively assessed outcomes and that fit into one of three categories: (1) those evaluating more versus less-intensive HTS, (2) those of populations receiving HTS versus not and (3) those evaluating outcomes after versus before HTS. We conducted meta-analyses using random-effects models.

RESULTS AND DISCUSSION

Of 29 980 studies screened, 76 studies were included. Thirty-eight studies were randomized controlled trials, 36 were cohort studies, one was quasi-experimental and one was a serial cross-sectional study. There was no significant difference in condom use among individuals receiving more-intensive HTS compared to less-intensive HTS (relative risk [RR]=1.03; 95% CI: 0.99 to 1.07). Condom use was significantly higher after receiving HTS compared to before HTS for individuals newly diagnosed with HIV (RR = 1.65; 95% CI: 1.36 to 1.99) and marginally significantly higher for individuals receiving an HIV-negative diagnosis (RR = 1.63; 95% CI: 1.01 to 2.62). Individuals receiving more-intensive HTS reported fewer sex partners at follow-up than those receiving less-intensive HTS, but the finding was not statistically significant (mean difference = -0.28; 95% CI: -3.66, 3.10).

CONCLUSIONS

Our findings highlight the importance of using limited resources towards HTS strategies that focus on early HIV diagnosis, treatment and prevention services rather than resources dedicated to supplementing or enhancing HTS with additional counselling or other interventions.

Perceived Knowledge of HIV-Negative Status Increases Condom Use Among Female Sex Workers in Zambian Transit Towns

Knowledge of HIV status is a necessary pre-condition for most HIV interventions, including treatment as well as biomedical and behavioral prevention interventions. We used data from a female sex worker (FSW) cohort in three Zambian transit towns to understand the effect that knowledge of HIV status has on FSWs' HIV risk-related sexual behaviors with clients. The cohort was formed from an HIV self-testing trial that followed participants for 4 months. Participants completed three rounds of data collection at baseline, 1 month, and 4 months where they reported their perceived knowledge of HIV status, number of clients on an average working night, and consistent condom use with clients. We measured the effect of knowledge of HIV status on participants' sexual behaviors by using linear regression models with individual fixed effects. The majority of the 965 participants tested for HIV at least once during the observation period (96%) and changed their knowledge of HIV status (79%). Knowledge of HIV status did not affect participants' number of clients, but it did affect their consistency of condom use. Compared with unknown HIV status, knowledge of HIV-negative status significantly increased participants' consistent condom use by 8.1% points [95% confidence interval (CI): 2.7–13.4, p = 0.003] and knowledge of HIV-positive status increased participants' consistent condom use by 6.1% points (95% CI: −0.1 to 12.9, p = 0.08); however, this latter effect was not statistically significant. FSWs in Zambia engaged in safer sex with clients when they learned their HIV status. The expansion of HIV testing programs may serve as a behavioral HIV prevention measure among FSWs.

Demand for self-tests: Evidence from a Becker-DeGroot-Marschak mechanism field experiment

Self-tests offer one approach for reducing frictions underlying low demand for preventive health inputs, yet there is little evidence on demand for self-tests. We used the Becker-DeGroot-Marschak mechanism-an incentive-compatible approach-to elicit exact willingness to pay (WTP) for HIV self-tests in a field experiment with 822 participants at 66 health clinics/pharmacies in Kenya. Our analysis reveals substantial demand at low prices and highly elastic demand at a wide range of prices above this range. We find few participants with nonpositive WTP. We examine correlates of WTP and discuss policy and research implications of our findings.

Bridging the Efficacy-Effectiveness Gap in HIV Programs: Lessons From Economics

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 nonhealth 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.

The effectiveness of using entertainment education narratives to promote safer sexual behaviors of youth: A meta-analysis, 1985-2017

BACKGROUND

Risky sexual behaviors are associated with the transmission of sexually transmitted infections (STIs) and unwanted pregnancies, both major health concerns for youth worldwide. This review studies the effectiveness of narrated mass media programs in promoting safer sexual practices among youth in developed and developing countries.

METHODS

Electronic and manual searches were conducted to identify experimental and quasi-experimental studies with robust counterfactual designs published between 1985 and the first quarter of 2017. Effect sizes were meta-analyzed using mixed-effects models.

RESULTS

Eight experimental and two quasi-experimental studies met our inclusion criteria. The aggregated sample size was 23,476 participants, with a median of 902 participants per study. Entertainment education narratives had small but significant effects for three sexual behaviors. It reduced the number of sexual partners [standardized mean difference, (SMD) = 0.17, 95% confidence interval (CI) = 0.02-0.33, three effect sizes], reduced unprotected sex (SMD = 0.08, 95% CI = 0.03-0.12, nine effect sizes), and increased testing and management for STIs (SMD = 0.29, 95% CI = 0.11-0.46, two effect sizes). The interventions were not effective in reducing inter-generational sex, measured through the age-gap with sexual partners (SMD = 0.06, 95% CI = -0.06-0.19, four effect sizes). Entertainment education had medium-size effects on knowledge outcomes (SMD = 0.67, 95% CI = 0.32-1.02, seven effect sizes), where a time-decay relationship is observed. No effects were found on attitudes.

CONCLUSION

Although mass media entertainment had small effects in promoting safer sexual practices, its economies of scales over face-to-face interventions suggest its potential to be a cost-effective tool above an audience threshold. The use of study participants from the general youth population and the use of mostly effectiveness trials mitigate concerns regarding its scalability. The overall paucity of high-quality studies affirms the need for strengthening the evidence base of entertainment education. Future research should be undertaken to understand the moderator effects for different subgroups and intervention characteristics.

Altruism in preventive health behavior: At-scale evidence from the HIV/AIDS pandemic

Preventive behavior with regards to disease transmission offers a promising context in which to provide empirical evidence on altruism in human populations. I examine the association between HIV status, own knowledge about status, and preventive health behavior using household survey data from over 200,000 individuals in 25 sub-Saharan African countries. I find that individuals who are HIV positive and have taken a standard HIV test are much more likely to engage in efforts to prevent HIV transmission than are individuals who are HIV negative and have taken a standard HIV test. Moreover, this difference is greater than the difference between HIV positives and HIV negatives for individuals who have not taken a standard HIV test. Consistent with an altruistic motivation, this double-difference is larger for individuals who are married than for individuals who are not married. These results appear to be the first evidence on the change in risky sexual behavior associated with HIV testing at scale and are consistent with altruism dominating any self-interested response to HIV testing.

Promotion and Persistence of HIV Testing and HIV/AIDS Knowledge: Evidence From a Randomized Controlled Trial in Ethiopia

We use data from a randomized controlled trial in Ethiopia and examine the causal effects of HIV/AIDS education, home-based voluntary HIV counseling and testing (VCT), and conditional cash transfers (CCT) for facility-based VCT on HIV/AIDS knowledge and demand for HIV testing. HIV/AIDS education significantly increases HIV/AIDS knowledge but has a limited effect on testing take-up. However, when HIV/AIDS education is combined with either home-based VCT or CCT for facility-based VCT, take-up increases substantially by about 63 and 57 percentage points, respectively. We also demonstrate evidence of persistence in test-taking behavior, where past HIV testing does not dampen demand for testing. Lastly, we find suggestive evidence that home-based VCT could be more effective at detecting HIV-positive cases relative to CCT for facility-based VCT. Our findings highlight the importance of geographic accessibility in the testing decision and persistence in demand for HIV testing. Copyright © 2016 John Wiley & Sons, Ltd.

Displacement of sexual partnerships in trials of sexual behavior interventions: A model-based assessment of consequences

We investigated the impact of the displacement of sexual activity from adherent recipients of an intervention to others within or outside a trial population on the results from hypothetical trials of different sexual behavior interventions. A short-term model of HIV-prevention interventions that lead to female rejection of male partnership requests showed the impact of displacement expected at the start of a trial. An agent-based model, with sexual mixing and other South African specific demographics, evaluated consequences of displacement for sexual behavior interventions targeting young females in South Africa. This model measured the cumulative incidence among adherent, non-adherent, control and non-enrolled females in a hypothetical trial of HIV prevention. When males made more than one attempt to seek a partnership, interventions reduced short-term HIV infection risk among adherent females, but increased it among non-adherent females as well as controls, non-enrolled (females eligible for the trial but not chosen to participate) and ineligible females (females that did not qualify for the trial due to age). The impact of displacement depends on the intervention and the adherence. In both models, the risk to individuals who are not members of the adherent intervention group will increase with displacement leading to a biased calculation for the effect estimates for the trial. Likewise, intent-to-treat effect estimates become nonlinear functions of the proportion adherent.

Factors that lead to changes in sexual behaviours after a negative HIV test: protocol for a prospective cohort study in Kinshasa

Background

Considering the high percentage of couples in which one or both members are HIV negative, the frequency of transmission among non-regular partners and the probabilities of non-disclosure, attention should be paid to people getting a negative HIV test at the Voluntary Counseling and Testing (VCT). Research has shown that a negative HIV test may be followed by a change in sexual behaviours. In Sub-Saharan Africa, where most HIV infections occur, there are few studies that have analysed the factors associated with changes in sexual risk behaviours after a negative HIV test at the VCT clinic. The aim of this project is to evaluate the specific factors associated with changes in sexual behaviours, three months after a negative result in an HIV test, and to analyse the effect of counseling and testing on HIV-related knowledge of participants in an outpatient centre of Kinshasa (Democratic Republic of Congo).

Methods and design

Prospective cohort study from December 2014 until March 2016. People 15–60 year old that received VCT at Monkole Hospital (Kinshasa) were followed three months after they got a negative HIV test. In a face-to-face interview, participants replied to a baseline and a follow-up research questionnaire on HIV-related knowledge, attitudes and behaviours. At follow-up respondents were also offered a new HIV test and additional HIV counseling. Four hundred and fifteen participants completed the baseline questionnaire and 363 (87 %) came back for their 3-month follow up.

Discussion

This is the first longitudinal study in the DRC that evaluates the factors associated with changes in sexual behaviours after a negative HIV test at the VCT. Participants attending the VCT services within a clinical setting are a good study population as they can be good transmitters of preventive information for other people with no access to health facilities.

How to sell a condom? The impact of demand creation tools on male and female condom sales in resource limited settings

Despite condoms being cheap and effective in preventing HIV, there remains an 8billion shortfall in condom use in risky sex-acts. Social marketing organisations apply private sector marketing approaches to sell public health products. This paper investigates the impact of marketing tools, including promotion and pricing, on demand for male and female condoms in 52 countries between 1997 and 2009. A static model differentiates drivers of demand between products, while a dynamic panel data estimator estimates their short- and long-run impacts. Products are not equally affected: female condoms are not affected by advertising, but highly affected by interpersonal communication and HIV prevalence. Price and promotion have significant short- and long-run effects, with female condoms far more sensitive to price than male condoms. The design of optimal distribution strategies for new and existing HIV prevention technologies must consider both product and target population characteristics.

Antiretroviral therapy and demand for HIV testing: Evidence from Zambia

This paper examines the effects of antiretroviral therapy (ART) on demand for HIV testing and of ART-induced testing on demand for risky sexual behavior. I provide a model of sexual behavior decision-making under uncertainty and estimate the structural parameters of the model using nationally representative survey data from Zambia on HIV testing decisions before and after the introduction of ART. The empirical results indicate that although the introduction of ART appears to have increased HIV testing rates by upwards of 50 percent, the ART allocation process may have limited the prevention benefit of ART-induced testing. Simulation results show that eliminating this prevention inefficiency while holding the supply of ART constant would increase the prevention impact of ART-induced testing more than four-fold. More generally, the analysis indicates that existing studies which examine "universal" testing or quasi-experimental testing programs understate the efficacy of standard voluntary counseling and testing programs.

The indirect impact of antiretroviral therapy: Mortality risk, mental health, and HIV-negative labor supply

To reduce the burden of the HIV/AIDS epidemic, international donors recently began providing free antiretroviral therapy (ART) in parts of Sub-Saharan Africa. ART dramatically prolongs life and reduces infectiousness for people with HIV. This paper shows that ART availability increases work time for HIV-negative people without caretaker obligations, who do not directly benefit from the medicine. A difference-in-difference design compares people living near and far from ART, before and after treatment becomes available. Next we explore the possible reasons for this pattern. Although we cannot pinpoint the mechanism, we find that ART availability substantially reduces subjective mortality risk and improves mental health. These results show an undocumented economic consequence of the HIV/AIDS epidemic and an important externality of medical innovation. They also provide the first evidence of a link between the disease environment and mental health.

Quasi-experiments to establish causal effects of HIV care and treatment and to improve the cascade of care

PURPOSE OF REVIEW

Randomized, population-representative trials of clinical interventions are rare. Quasi-experiments have been used successfully to generate causal evidence on the cascade of HIV care in a broad range of real-world settings.

RECENT FINDINGS

Quasi-experiments exploit exogenous, or quasi-random, variation occurring naturally in the world or because of an administrative rule or policy change to estimate causal effects. Well designed quasi-experiments have greater internal validity than typical observational research designs. At the same time, quasi-experiments may also have potential for greater external validity than experiments and can be implemented when randomized clinical trials are infeasible or unethical. Quasi-experimental studies have established the causal effects of HIV testing and initiation of antiretroviral therapy on health, economic outcomes and sexual behaviors, as well as indirect effects on other community members. Recent quasi-experiments have evaluated specific interventions to improve patient performance in the cascade of care, providing causal evidence to optimize clinical management of HIV.

SUMMARY

Quasi-experiments have generated important data on the real-world impacts of HIV testing and treatment and on interventions to improve the cascade of care. With the growth in large-scale clinical and administrative data, quasi-experiments enable rigorous evaluation of policies implemented in real-world settings.