HIV-1 incidence rates and risk factors in agricultural workers and dependents in rural Kenya: 36-month follow-up of the Kericho HIV cohort study

Men's understanding of three different measures of transactional sex: A cognitive interviewing study among men in Rakai, Uganda

Lack of valid and reliable measures and inconsistent transactional sex (TS) measurement has resulted in poor understanding of the practice, particularly among men. To improve TS measurement and facilitate comparison across studies, we examined how men comprehend and respond to three common TS measures. We conducted cognitive interviews with 25 sexually active adult men in Rakai, Uganda from November 2021-February 2022 and thematically analysed the data. Most men responded affirmatively to the three TS measures, but there was variation in responses across measures. The two measures that assessed relationship motivation and gendered norms of material provision for sex showed better comprehension and consistency than the measure without these components. For these two measures, a substantial proportion of men responded affirmatively but provided explanations related to gendered expectations of material provision rather than describing provision in a specific relationship which was not the intent of the measures. The measure developed by Wamoyi and colleagues appeared to most accurately measure TS. Our findings support TS measures that include a clear statement of motivation and account for gendered norms of giving and receiving. Given heterogeneity in TS measurement, this study enhances our understanding of common TS measures.

Hepatitis and tuberculosis testing are much less common than HIV testing among adults in Kisumu, Kenya: results from a cross-sectional assessment

Background

Kenya has a high burden of HIV, viral hepatitis, and tuberculosis. Screening is necessary for early diagnosis and treatment, which reduces morbidity and mortality across all three illnesses. We evaluated testing uptake for HIV, viral hepatitis, and tuberculosis in Kisumu, Kenya.

Methods

Cross-sectional data from adults aged 18–35 years who enrolled in a prospective HIV incidence cohort study from February 2017 to May 2018 were analyzed. A questionnaire was administered to each participant at screening for study eligibility to collect behavioral characteristics and to assess prior testing practices. Among participants without a history of previously-diagnosed HIV, multivariable robust Poisson regression was used to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for factors potentially associated with HIV testing in the 12 months prior to enrollment. A hierarchical model was used to test for differential access to testing due to spatial location.

Results

Of 671 participants, 52 (7.7%) were living with HIV, 308 (45.9%) were female, and the median age was 24 (interquartile range 21–28) years. Among 651 (97.0%) who had ever been tested for HIV, 400 (61.2%) reported HIV testing in the past 6 months, 129 (19.7%) in the past 6–12 months, and 125 (19.1%) more than one year prior to enrollment. Any prior testing for viral hepatitis was reported by 8 (1.2%) participants and for tuberculosis by 51 (7.6%). In unadjusted models, HIV testing in the past year was more common among females (PR 1.08 [95% CI 1.01, 1.17]) and participants with secondary education or higher (PR 1.10 [95% CI 1.02, 1.19]). In the multivariable model, only secondary education or higher was associated with recent HIV testing (adjusted PR 1.10 [95% CI 1.02, 1.20]). Hierarchical models showed no geographic differences in HIV testing across Kisumu subcounties.

Conclusions

Prior HIV testing was common among study participants and most had been tested within the past year but testing for tuberculosis and viral hepatitis was far less common. HIV testing gaps exist for males and those with lower levels of education. HIV testing infrastructure could be leveraged to increase access to testing for other endemic infectious diseases.

Transactional sex and HIV infection among commercial farm workers in South Africa

Background

High prevalence of HIV infection has been reported among commercial farm workers in South Africa, but studies of the role of transactional sex in this epidemic is limited.

Objective

This study seeks to examine the association between transactional sex and HIV infection among commercial farm workers in South Africa.

Methods

This is a cross-sectional secondary data analysis of the Integrated Biological and Behavioural Surveillance Survey by the International Organization of Migration among farm workers in Mpumalanga and Limpopo Provinces, South Africa in 2010. The study included 2,758 sexually active farm workers. The outcome variable was HIV infection while the main explanatory variable was engagement in transactional sex. Other explanatory variables were sex, age, marital status, number of sex partners, food security, recent history of sexually transmitted infection, condom use at last sex with non-regular partner, history of sexual violence and migration status. Bivariate and multivariable logistic regression analyses were done to obtain unadjusted and adjusted odds ratios of the association between transactional sex and HIV infection.

Results

Engagement in transactional sex was common (19%) but not significantly associated with HIV infection (OR 1.1; CI 0.57-2.44). Female sex (1.93; 1.60-2.32), age 25 to 44 years, recent STI (OR 1.37; CI 1.18-1.58) and sexual violence (OR 1.39; CI 1.19-1.63) were significant risk factors for HIV infection.

Conclusion

Risky sexual behaviours were common among the farmworker population. HIV prevention interventions should include behavioural change communication and improved access to healthcare for STI and HIV treatment.

Modeling and mapping the burden of disease in Kenya

Precision public health approaches are crucial for targeting health policies to regions most affected by disease. We present the first sub-national and spatially explicit burden of disease study in Africa. We used a cross-sectional study design and assessed data from the Kenya population and housing census of 2009 for calculating YLLs (years of life lost) due to premature mortality at the division level (N = 612). We conducted spatial autocorrelation analysis to identify spatial clusters of YLLs and applied boosted regression trees to find statistical associations between locational risk factors and YLLs. We found statistically significant spatial clusters of high numbers of YLLs at the division level in western, northwestern, and northeastern areas of Kenya. Ethnicity and household crowding were the most important and significant risk factors for YLL. Further positive and significantly associated variables were malaria endemicity, northern geographic location, and higher YLL in neighboring divisions. In contrast, higher rates of married people and more precipitation in a division were significantly associated with less YLL. We provide an evidence base and a transferable approach that can guide health policy and intervention in sub-national regions afflicted by disease burden in Kenya and other areas of comparable settings.

Transactional sex and risk for HIV infection in sub-Saharan Africa: a systematic review and meta-analysis

INTRODUCTION

Young women aged 15 to 24 years in sub-Saharan Africa continue to be disproportionately affected by HIV. A growing number of studies have suggested that the practice of transactional sex may in part explain women's heightened risk, but evidence on the association between transactional sex and HIV has not yet been synthesized. We set out to systematically review studies that assess the relationship between transactional sex and HIV among men and women in sub-Saharan Africa and to summarize the findings through a meta-analysis.

METHODS

The search strategy included 8 databases, hand searches in 10 journals, and searches across 17 websites and portals for organizations as informed by expert colleagues. A systematic review of cross-sectional and longitudinal studies was carried out for studies on women and men who engage in transactional sex published up through 2014. Random effects meta-analysis was used to further examine the relationship between transactional sex and prevalent HIV infection across a subset of studies with the same exposure period. Analyses were conducted separately for men and women.

RESULTS

Nineteen papers from 16 studies met our inclusion criteria. Of these 16 studies, 14 provided data on women and 10 on men. We find a significant, positive, unadjusted or adjusted association between transactional sex and HIV in 10 of 14 studies for women, one of which used a longitudinal design (relative risk (RR)=2.06, 95% confidence interval (CI): 1.22 -3.48). Out of 10 studies involving men, only 2 indicate a positive association between HIV and transactional sex in unadjusted or adjusted models. The meta-analysis confirmed general findings from the systematic review (unadjusted meta-analysis findings are significant for women (n=4; pooled odds ratio (OR)=1.54, 95% CI: 1.04-2.28; I2=42.5%, p=0.156), but not for men (n=4; pooled OR=1.47, 95% CI: 0.85-2.56; I2=50.8%, p=0.107).

CONCLUSIONS

Transactional sex is associated with HIV among women, whereas findings for men were inconclusive. Given that only two studies used a longitudinal approach, there remains a need for better measurement of the practice of transactional sex and additional longitudinal studies to establish the causal pathways between transactional sex and HIV.

The Number and Complexity of Pure and Recombinant HIV-1 Strains Observed within Incident Infections during the HIV and Malaria Cohort Study Conducted in Kericho, Kenya, from 2003 to 2006

Characterization of HIV-1 subtype diversity in regions where vaccine trials are conducted is critical for vaccine development and testing. This study describes the molecular epidemiology of HIV-1 within a tea-plantation community cohort in Kericho, Kenya. Sixty-three incident infections were ascertained in the HIV and Malaria Cohort Study conducted in Kericho from 2003 to 2006. HIV-1 strains from 58 of those individuals were full genome characterized and compared to two previous Kenyan studies describing 41 prevalent infections from a blood bank survey (1999–2000) and 21 infections from a higher-risk cohort containing a mix of incident and prevalent infections (2006). Among the 58 strains from the community cohort, 43.1% were pure subtypes (36.2% A1, 5.2% C, and 1.7% G) and 56.9% were inter-subtype recombinants (29.3% A1D, 8.6% A1CD, 6.9% A1A2D, 5.2% A1C, 3.4% A1A2CD, and 3.4% A2D). This diversity and the resulting genetic distance between the observed strains will need to be addressed when vaccine immunogens are chosen. In consideration of current vaccine development efforts, the strains from these three studies were compared to five candidate vaccines (each of which are viral vectored, carrying inserts corresponding to parts of gag, pol, and envelope), which have been developed for possible use in sub-Saharan Africa. The sequence comparison between the observed strains and the candidate vaccines indicates that in the presence of diverse recombinants, a bivalent vaccine is more likely to provide T-cell epitope coverage than monovalent vaccines even when the inserts of the bivalent vaccine are not subtype-matched to the local epidemic.

Kericho CLinic-based ART Diagnostic Evaluation (CLADE): design, accrual, and baseline characteristics of a randomized controlled trial conducted in predominately rural, district-level, HIV clinics of Kenya

Background

Prospective clinical trial data regarding routine HIV-1 viral load (VL) monitoring of antiretroviral therapy (ART) in non-research clinics of Sub-Saharan Africa are needed for policy makers.

Methods

CLinic-based ART Diagnostic Evaluation (CLADE) is a randomized, controlled trial (RCT) evaluating feasibility, superiority, and cost-effectiveness of routine VL vs. standard of care (clinical and immunological) monitoring in adults initiating dual nucleoside reverse transcriptase inhibitor (NRTI)+non-NRTI ART. Participants were randomized (1:1) at 7 predominately rural, non-research, district-level clinics of western Kenya. Descriptive statistics present accrual patterns and baseline cohort characteristics.

Results

Over 15 months, 820 adults enrolled at 7 sites with 86–152 enrolled per site. Monthly site enrollment ranged from 2–92 participants. Full (100%) informed consent compliance was independently documented. Half (49.9%) had HIV diagnosed through voluntary counseling and testing. Study arms were similar: mostly females (57.6%) aged 37.6 (SD = 9.0) years with low CD4 (166 [SD = 106]) cells/m³). Notable proportions had WHO Stage III or IV disease (28.7%), BMI <18.5 kg/m² (23.1%), and a history of tuberculosis (5.6%) or were receiving tuberculosis treatment (8.2%) at ART initiation. In the routine VL arm, 407/409 (99.5%) received baseline VL (234,577 SD = 151,055 copies/ml). All participants received lamivudine; 49.8% started zidovudine followed by 38.4% stavudine and 11.8% tenofovir; and, 64.4% received nevirapine as nNRTI (35.6% efavirenz).

Conclusions

A RCT can be enrolled successfully in rural, non-research, resource limited, district-level clinics in western Kenya. Many adults presenting for ART have advanced HIV/AIDS, emphasizing the importance of universal HIV testing and linkage-to-care campaigns.

Trial Registration

ClinicalTrials.gov NCT01791556

Investigation of HIV Incidence Rates in a High-Risk, High-Prevalence Kenyan Population: Potential Lessons for Intervention Trials and Programmatic Strategies

Cost-effective HIV prevention programs should target persons at high risk of HIV acquisition. We conducted an observational HIV incidence cohort study in Kisumu, Kenya, where HIV prevalence is triple that of the national rate. We used referral and venue-sampling approaches to enroll HIV-negative persons for a 12-month observational cohort, August 2010 to September 2011, collected data using computer-assisted interviews, and performed HIV testing quarterly. Among 1292 eligible persons, 648 (50%) were excluded for HIV positivity and other reasons. Of the 644 enrollees, 52% were women who were significantly older than men (P<.01). In all, 7 persons seroconverted (incidence rate [IR] per 100 person-years=1.11; 95% confidence interval [CI] 0.45-2.30), 6 were women; 5 (IR=3.14; 95% CI 1.02-7.34) of whom were ≤25 years. Most new infections occurred in young women, an observation consistent with other findings in sub-Saharan Africa that women aged ≤25 years are an important population for HIV intervention trials in Africa.

Novel directions in HIV-1 vaccines revealed from clinical trials

PURPOSE OF REVIEW

Considerable HIV-1 vaccine development efforts have been deployed over the past decade. Put into perspective, the results from efficacy trials and the identification of correlates of risk have opened large and unforeseen avenues for vaccine development.

RECENT FINDINGS

The Thai efficacy trial, RV144, provided the first evidence that HIV-1 vaccine protection against HIV-1 acquisition could be achieved. The correlate of risk analysis showed that IgG antibodies against the gp120 V2 loop inversely correlated with a decreased risk of infection, whereas Env-specific IgA directly correlated with risk. Further clinical trials will focus on testing new envelope subunit proteins formulated with adjuvants capable of inducing higher and more durable functional antibody responses (both binding and broadly neutralizing antibodies). Moreover, vector-based vaccine regimens that can induce cell-mediated immune responses in addition to humoral responses remain a priority.

SUMMARY

Future efficacy trials will focus on prevention of HIV-1 transmission in heterosexual population in Africa and MSM in Asia. The recent successes leading to novel directions in HIV-1 vaccine development are a result of collaboration and commitment among vaccine manufacturers, funders, scientists and civil society stakeholders. Sustained and broad collaborative efforts are required to advance new vaccine strategies for higher levels of efficacy.

Risk factors for HIV-1 infection in a longitudinal, prospective cohort of adults from the Mbeya Region, Tanzania

BACKGROUND

To control the global HIV epidemic, targeted interventions to reduce the incidence of HIV infections are urgently needed until an effective HIV vaccine is available. This study describes HIV-1 incidence and associated risk factors in a general population cohort of adults from Mbeya region, Tanzania, who participated in a vaccine preparedness study.

METHODS

We conducted a closed prospective cohort study with 6-monthly follow-up from 2002 to 2006 enrolling adults from the general population. HIV-1 incidence and risk factors for HIV-1 acquisition were analyzed using Cox regression.

RESULTS

We observed 2578 seronegative participants for a mean period of 3.06 person years (PY) (7471 PY in total). Overall HIV-1 incidence was 1.35 per 100 PY (95% confidence interval [CI], 1.10-1.64/100 PY). The highest overall HIV-1 incidence was found in females from Itende village (1.55 per 100 PY; 95% CI, 0.99-2.30/100 PY); the highest age-specific incidence was observed in semiurban males aged 30 to 34 years (2.75 per 100 PY; 95% CI, 0.75-7.04). HIV-1 acquisition was independently associated with female gender (hazard ratio [HR], 1.64; 95% CI, 1.05-2.57), younger age at enrollment (age 18-19 versus 35-39 years: HR, 0.29; 95% CI, 0.11-0.75), alcohol consumption (almost daily versus none: HR, 2.01; 95% CI, 1.00-4.07), education level (secondary school versus none: HR, 0.39; 95% CI, 0.17-0.89), and number of lifetime sex partners (more than five versus one: HR, 2.22; 95% CI, 1.13-4.36).

CONCLUSIONS

A high incidence of HIV was observed in this cohort, and incident infection was strongly associated with young age, alcohol consumption, low school education level, and number of sex partners. Targeted interventions are needed to address the elevated risk associated with these factors.

HIV vaccines: current status worldwide and in Africa

Since HIV-1 was identified, development of a preventive vaccine has been a major goal. Significant progress toward that goal has been made by 2010. In macaques, a vigorous T effector cell response has protected some animals from disease caused by simian immunodeficiency virus (SIV). Broadly, neutralizing human anti-HIV antibodies have been isolated and their structures, and targets are rapidly being elucidated. For the first time an AIDS vaccine has shown modest protective efficacy in a human clinical trial. To reach the final goal, there is a need for a coordinated global effort, including a range of approaches including novel high-throughput screening techniques, X-ray crystallography, and monoclonal antibody isolation, analysis of T cell responses and their impact on disease progression, human epidemiology, as well as targeted studies in nonhuman primates. African research teams as well as cohorts of healthy volunteers and HIV-infected individuals have contributed to HIV vaccine research and development in many important ways. It is essential that this work continue to speed the development and deployment of a vaccine suitable for African populations.

Male circumcision for HIV prevention: current research and programmatic issues

Randomized controlled trials in sub-Saharan Africa have shown that adult male circumcision reduces the risk of HIV acquisition in men by about 60%. In this article, we review recent data on the association of male circumcision and HIV/sexually transmitted infection in men and women. This includes a summary of data showing some evidence of an effect of male circumcision against genital ulcer disease, HSV-2 infection, human papillomavirus and Trichomonas vaginalis, but not Chlamydia trachomatis or Neisseria gonorrhoea in men. Longitudinal studies among HIV discordant couples suggest that male circumcision may provide some direct long-term benefit to women, which may start after complete wound healing. Circumcision may also protect against HIV acquisition in men who have sex with men (MSM) and those who practice unprotected anal intercourse (either exclusively or predominantly), although these data are not consistent. To date, there is little evidence from the few studies available of either unsafe practices or reported increases in risky behaviour, or adverse changes in sexual satisfaction and function. As countries in southern and eastern Africa scale up services, operational research will likely be useful to iteratively improve programme delivery and impact while identifying the best methods of integrating safe male circumcision services into HIV prevention strategies and strengthening health systems.