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All cohorts are conditioned on survival to a study's baseline. The validity of estimates drawn from these cohorts of survivors may be compromised if those who die prior to enrollment have different covariate structures than survivors. In this research note, we used data from the "HAALSI Cohort" (Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa) of older adults in rural South Africa and a "Mortality Cohort" of individuals who would have been eligible for HAALSI but died before they had the opportunity to enroll, drawing on complete population mortality data from the Agincourt Health and Socio-Demographic Surveillance System. We simulated the prevalence of cognitive impairment under different assumptions about the prevalence of such impairment in the Mortality Cohort. We constructed a random forest classification model to predict cognitive impairment in the Mortality Cohort and compared it with observed estimates in the HAALSI Cohort. The prevalence of cognitive impairment was sensitive to assumptions about the prevalence in the Mortality Cohort. The predictive model revealed meaningfully higher predicted probability of cognitive impairment in a counterfactual scenario with no prebaseline deaths. Researchers should consider prebaseline mortality in the interpretation of prevalence estimates, especially when the magnitude of prebaseline deaths is likely large.

Background: Blended digital mental health interventions combining technology with human support are more effective than stand-alone treatments. However, limited research has examined how to train and supervise personnel delivering human support components. The Kuamsha app, a gamified digital intervention for adolescent depression based on behavioral activation, was designed to be paired with low-intensity telephone-based peer support. A structured training and supervision program for peer supporters was codeveloped through workshops with mental health professionals and youth with lived experience of mental health challenges in South Africa and Uganda. To the best of our knowledge, this is the first study to evaluate a structured peer mentor model within a digital mental health intervention in low- and middle-income countries.

Objective: This study assessed the feasibility, acceptability, and fidelity of a training and supervision program for peer supporters delivering a digital mental health intervention in South Africa and Uganda.

Methods: We conducted a mixed methods evaluation of the peer mentor program. Quantitative metrics assessed the feasibility of recruitment, retention, and attendance among peer mentors (n=13, South Africa; n=4, Uganda), as well as training acceptability. Fidelity, adherence, and competence were scored at the session level and converted to percentages of the maximum possible score. Linear mixed-effects regression models with a random intercept for provider and site estimated adjusted marginal means (95% CI). In-depth interviews and focus group discussions explored program acceptability and implementation factors.

Results: The peer mentor training and supervision program was feasible and acceptable in both settings, with high recruitment (South Africa: n=13/19, 68%; Uganda: 4/4, 100%), retention (South Africa: 9/13, 69%; Uganda: 4/4, 100%), and training attendance rates (89%‐92% in South Africa and 100% in Uganda), alongside qualitative reports of high satisfaction. All peer mentors met a minimum posttraining competency threshold (≥50%), with median competency scores of 70.7% (IQR 45.8%‐78.2%) in South Africa and 75.4% (IQR 73.8%‐77.3%) in Uganda. Independent ratings of recorded calls indicated high overall fidelity in South Africa (84.7%, 95% CI 80.3%‐89.0%) and Uganda (87.7%, 95% CI 83.4%‐92.1%). Adherence was higher in Uganda than South Africa (adjusted mean difference [AMD] 13.30 percentage points, 95% CI 8.99‐17.61; P<.001), as was competence (AMD 4.88 percentage points, 95% CI 1.23‐8.53; P=.009). The AMD in overall fidelity (3.06 percentage points, 95% CI −0.98 to 7.10) was not statistically significant (P=.14). The qualitative findings emphasized the value of ongoing supervision and capacity development, interactive training approaches, and blended delivery models.

Conclusions: Locally adapted training and supervision models can strengthen peer mentor capabilities to support digital interventions. Adequate supervisory capacity and incentive structures are critical to sustain engagement, retention, and fidelity. In settings with frequent network disruptions, periodic in-person contact between peer mentors and supervisors may enhance fidelity. Future research should examine how peer mentor fidelity influences user engagement and mental health outcomes.

Introduction and methods: In a cohort study, enrolling new households annually during 2016–2018, we estimated the B. pertussis attack rate using serology and PCR, identified factors associated with seroconversion, and described antibody changes over time. Nasopharyngeal swabs were collected biweekly for 6–10 months annually, with cases defined as individuals testing PCR-positive at least once. Seroconversion was defined as a ≥4-fold increase in anti-pertussis toxin IgG concentration between consecutive blood draws. Logistic regression was used to identify factors associated with seroconversion among PCR-positive individuals.

Results: Among 1509 participants, the serology attack rate was 5.8% (87/1509), 6.2% (94/1509) by PCR, and 9.6% (145/1509) combining both methods. Among PCR-positive cases, 38.3% (36/94) seroconverted, with a mean time to seroconversion of 2.9 months (range: 3 weeks–5.9 months). Younger participants (5–18 years) (adjusted odds ratio (aOR) 6.8, 95% confidence interval (CI) 1.3–35.1) and those with episode durations of ≥7 days (aOR 13.3, 95% CI 3.4–51.1) were more likely to seroconvert. Among the seroconverted, 75.0% (27/36) maintained antibody concentrations >40 IU/ml for at least 12 months post-infection.

Discussion: Almost 10% of participants had B. pertussis infection during follow-up. Less than half of individuals with PCR-confirmed infection seroconverted but maintained elevated antibodies for at least one-year post-infection.

Background: The COVID-19 pandemic has impacted the provision and utilisation of health care services with varying magnitude across settings due to spatial temporal variation in the burden of COVID-19 cases and the roll-out of local COVID-19 response policies. This study assesses changes in the provision and utilisation of health care services for three major chronic health conditions (HIV/AIDS, hypertension, and diabetes) over the pre-COVID-19 and COVID-19 pandemic periods in a rural South African sub-district of Agincourt.

Methods: Segmented interrupted time series regression models are applied to assess changes in the number of medication collection visits and new diagnoses for HIV/AIDS, hypertension, and diabetes from 1 January 2018 to 30 September 2021 covering the pre- COVID-19 period and the first three waves of the COVID-19 pandemic.

Results: The number of medication collection visits for HIV/AIDS, hypertension, and diabetes dropped following the imposition of level 5 lockdown. Despite some improvements over the course of the pandemic, by the end of the third wave in September 2021, visits remained below the pre-COVID-19 era. The number of clinic visits for new diagnoses of HIV/AIDS and hypertension also fell after the introduction of level 5 lockdown. Although the number of new visits for HIV/AIDS bounced back to the pre-COVID-19 trends by the end of the third wave, the number of visits for new hypertension diagnoses remained significantly lower than expected. Referrals for collection of medications from the Central Chronic Medicines Dispensing and Distribution (CCMDD) programme, as an alternative to collection from clinics, increased exponentially over the course of the pandemic.

Conclusions: Although the increased adoption of the CCMDD programme can in part account for decreased medication collection visits which persisted well after lockdown measures were lifted, marked reductions in the number of newly diagnosed cases of hypertension warrant concern. A deeper assessment of the appropriateness of referrals to the CCMDD programme as well as the longer-term effects on morbidity and mortality of missed treatment and/or delayed diagnosis is needed for a more granular understanding of the true ramifications of the COVID-19 pandemic and associated lockdown policies in the Agincourt subdistrict and other rural African settings.

Background: Cash transfers are a promising but understudied intervention that may protect cognitive function in adults. Although South Africa has a rapidly ageing population, little is known about the nature of association between cash transfers and cognitive function in this setting. Objectives We leveraged age-eligibility expansions to South Africa's Child Support Grant (CSG) to investigate the association between duration of CSG eligibility and cognitive function of biological mothers of child beneficiaries in South Africa.

Methods: We analysed 2014/2015 baseline data from 944 women, aged 40–59 years with at least one CSG-eligible child, enrolled in the population-representative HAALSI cohort in Agincourt, South Africa. Duration of CSG eligibility for each mother was calculated based on the birth dates of all their children and the CSG age-eligibility expansion years (2003–2012). Cognitive function was measured using a cognitive battery administered at the HAALSI baseline interview. Linear regression was used to estimate the association between duration of CSG eligibility, dichotomized as low (≤10 years) and high (>10 years) eligibility, and cognitive function z-scores of the mothers.

Results: High vs. low duration of CSG eligibility, was associated with higher cognitive function z-scores in the full sample [β: 0.15 SD units; 95% CI: 0.04, 0.26; p-value = 0.01]. In mothers with one to four lifetime children, but not five or more, high vs. low duration of CSG eligibility, was associated with higher cognitive function z-scores [β: 0.19 SD units; 95% CI: 0.05, 0.34, p-value = 0.02].

Conclusion: Government cash transfers given to support raising children may confer substantial protective effects on the subsequent cognitive function of mothers. Further studies are needed to understand how parity may influence this relationship. Our findings bring evidence to policymakers for designing income supplementation programmes to promote healthy cognitive ageing in low-income settings.

Evidence on cash transfers as a population-level intervention to support healthy cognitive aging in low-income settings is sparse. We assessed the effect of a cash transfer intervention on cognitive aging outcomes in older South African adults. We leveraged the overlap in the sampling frames of a Phase 3 randomized cash transfer trial [HIV Prevention Trial Network (HPTN) 068, 2011-2015] and an aging cohort [Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community (HAALSI), 2014-2022] in rural Mpumalanga Province, South Africa. In 2011/12, young women and their primary caregivers were randomly assigned 1:1 to receive a monthly cash transfer or control. In 2014/2015, 862 adults aged 40+ y living in trial households were enrolled in the HAALSI cohort, with cognitive data collected in three waves over 7 y. We estimated the impact of the intervention on rate of memory decline and dementia probability scores. Memory decline in the cash transfer arm was 0.03 SD units (95% CI: 0.002, 0.05) slower per year than in the control arm. Dementia probability scores were three percentage points lower in the cash transfer arm than the control arm (β = -0.03; 95% CI: -0.05, -0.001). Effects were consistent across subgroups. A modestly sized household cash transfer delivered over a short period in mid- to later-life led to a meaningful slowing of memory decline and reduction in dementia probability 7 y later. Cash transfer programs could help stem the tide of new dementia cases in economically vulnerable populations in the coming decades.

Objective: Biological markers of stress have been associated with HIV progression and pathogenesis but not with HIV incidence. We sought to determine if elevated stress-responsive biomarkers would be associated with incident HIV among adolescent girls and young women (AGYW).

Design: We conducted a case-cohort study within the HIV Prevention Trials Network (HPTN) 068 study among 949 AGYW in South Africa. Cases were AGYW who tested HIV-positive during the eight-year follow-up. Unmatched controls were randomly selected from the HIV-negative population at enrollment.

Methods: Dried blood spots from cases and controls were tested from enrollment (2011-2012) for C-reactive protein (CRP), herpes simplex virus type-1 (HSV-1) antibody titers, and cytomegalovirus (CMV) antibody titers. Cox proportional hazards models estimated the association between each biomarker and time to incident HIV.

Results: Compared to AGYW with the lowest CRP levels, those with medium and high CRP levels had a higher hazard ratio (HR) of incident HIV (HR: 1.45, 95% CI: 0.95, 2.21; HR: 1.50, 95% CI: 0.98,2.30, respectively), although not statistically significant. The relative hazard of incident HIV was also higher among AGYW who were CMV seropositive vs. seronegative (low antibodies HR: 2.18, 95% CI: 1.2,3.87; medium HR: 2.25, 95% CI: 1.28,3.95; high HR: 1.78, 95% CI: 0.99,3.21). Those with the highest HSV-1 antibody levels experienced an increased hazard of HIV compared to those who were HSV-1 seronegative (HR: 1.58, 95% CI: 1.03,2.44).

Conclusions: Biological stress may increase AGYW’s susceptibility to HIV acquisition through changes in immune function, viral infection, and increased biological vulnerability to disease.

Introduction: Aging populations across sub-Saharan Africa are rapidly expanding, leading to an increase in the burden of Alzheimer's disease and related dementias (ADRD). Cash transfer interventions are one plausible mechanism to combat ADRD at a population-level in low-income settings. We exploited exogenous variation in eligibility for South Africa's Child Support Grant (CSG) to estimate the longitudinal association between potential CSG benefit and cognitive trajectories in rural mothers with <10 children (n = 1090).

Methods: South Africa's CSG delivers monthly cash payments to primary caregivers, predominantly mothers, to offset the costs associated with child rearing. This study implemented a quasi-experimental design using data (2014–2022) from a rural, low-income cohort in the Agincourt research area, South Africa. We fit linear mixed effects models and generalized linear models to estimate the association of potential CSG benefit per eligible child with memory decline and dementia probability, respectively. We stratified all models by the mother's total number of children (1–4 and 5–9) and examined effect modification by household wealth and the mother's education level.

Results: Having above median CSG per eligible child was associated with higher baseline memory scores (β = 0.12 SD units, 95% CI = 0.02, 0.22) but steeper memory decline (β = −0.02 SD units, 95% CI = −0.04, -0.00) compared to below median CSG. Within stratified analyses, this effect was primarily observed among mothers with 5–9 children. No associations were observed between potential CSG per eligible child and dementia probability.

Conclusions: Our findings support the use of large-scale cash transfers as a promising intervention to promote healthy cognitive aging in mid-life women within rural, low-income settings. However, we found evidence that the CSG in its current structure may not be sufficient support for women to sustain measurable cognitive benefits over the long-term.

Objective: To compare the causes of death for women who died during pregnancy and within the first 42 days postpartum with those of women who died between >42 days and within 1 year postpartum.

Design: Open population cohort (Health and Demographic Surveillance Systems).

Setting: Ten Health and Demographic Surveillance Systems (HDSS) in The Gambia, Kenya, Malawi, Tanzania, Ethiopia and South Africa.

Population: 2114 deaths which occurred within 1 year of the end of pregnancy where a verbal autopsy interview was conducted from 2000 to 2019.

Methods: InterVA5 and InSilicoVA verbal autopsy algorithms were used to attribute the most likely underlying cause of death, which were grouped according to adapted International Classification of Diseases-Maternal Mortality categories. Multinomial regression was used to compare differences in causes of deaths within 42 days versus 43–365 days postpartum adjusting for HDSS and time period (2000–2009 and 2010–2019).

Main outcome measures: Cause of death and the verbal autopsy Circumstances of Mortality Categories (COMCATs).

Results: Of 2114 deaths, 1212 deaths occurred within 42 days postpartum and 902 between 43 and 365 days postpartum. Compared with deaths within 42 days, deaths from HIV and TB, other infectious diseases, and non-communicable diseases constituted a significantly larger proportion of late pregnancy-related deaths beyond 42 days postpartum, and health system failures were important in the circumstances of those deaths. The contribution of HIV and TB to deaths beyond 42 days postpartum was greatest in Southern Africa. The causes of pregnancy-related mortality within and beyond 42 days postpartum did not change significantly between 2000–2009 and 2010–2019.

Conclusions: Cause of death data from the extended postpartum period are critical to inform prevention. The dominance of HIV and TB, other infectious and non-communicable diseases to (late) pregnancy-related mortality highlights the need for better integration of non-obstetric care with ante-, intra- and postpartum care in high-burden settings.

Purpose: To assess the relationship between school environment and health and behavior outcomes.

Methods: Data are from baseline and first follow-up of the HIV Prevention Trials Network (HPTN) 068 longitudinal trial established in 2012 of adolescent girls and young women in rural Mpumalanga Province, South Africa. Data from 2212 participants are included. We measured the association between four school environment domains: school resources, school safety, negative personal experiences, and school connectedness, and several health and behavior outcomes: depressive symptoms, low attendance, recent pregnancy, recent unprotected sex, transactional sex, and having an older romantic partner. We used a g-computation approach to estimate risk differences (RD) for the longitudinal relationship between the school environment (measured at the individual and school level) on individual health and behavior outcomes, controlling for baseline covariates.

Results: The mean age of participants at baseline was 15.4; mean age at first follow-up was 16.6. Individual baseline perceptions of an unsafe school environment (RD = 3.1 %, 95 % CI: 1.3–5.2 %) and more frequent negative experiences (RD = 4.0 %, 95 % CI: 2.0–5.9 %) were associated with higher absolute risk of depressive symptoms at follow-up. There was an overall trend toward higher risk of pregnancy, unprotected sex, and having an older partner among those who reported fewer school resources, lack of school safety, more negative personal experiences, and lack of school connectedness.

Conclusions: Our findings provide evidence of an overall trend toward higher risk of depression, pregnancy, unprotected sex, and having an older partner among those reporting a worse school environment across four school environment domains.