Leveraging data science and machine learning for urban climate adaptation in two major African cities: a HE2AT Center study protocol.

INTRODUCTION: African cities, particularly Abidjan and Johannesburg, face challenges of rapid urban growth, informality and strained health services, compounded by increasing temperatures due to climate change. This study aims to understand the complexities of heat-related health impacts in these cities. The objectives are: (1) mapping intraurban heat risk and exposure using health, socioeconomic, climate and satellite imagery data; (2) creating a stratified heat-health forecast model to predict adverse health outcomes; and (3) establishing an early warning system for timely heatwave alerts. The ultimate goal is to foster climate-resilient African cities, protecting disproportionately affected populations from heat hazards. METHODS AND ANALYSIS: The research will acquire health-related datasets from eligible adult clinical trials or cohort studies conducted in Johannesburg and Abidjan between 2000 and 2022. Additional data will be collected, including socioeconomic, climate datasets and satellite imagery. These resources will aid in mapping heat hazards and quantifying heat-health exposure, the extent of elevated risk and morbidity. Outcomes will be determined using advanced data analysis methods, including statistical evaluation, machine learning and deep learning techniques. ETHICS AND DISSEMINATION: The study has been approved by the Wits Human Research Ethics Committee (reference no: 220606). Data management will follow approved procedures. The results will be disseminated through workshops, community forums, conferences and publications. Data deposition and curation plans will be established in line with ethical and safety considerations.

Impacts of heat exposure in utero on long-term health and social outcomes: a systematic review.

BACKGROUND: Climate change, particularly global warming, is amongst the greatest threats to human health. While short-term effects of heat exposure in pregnancy, such as preterm birth, are well documented, long-term effects have received less attention. This review aims to systematically assess evidence on the long-term impacts on the foetus of heat exposure in utero. METHODS: A search was conducted in August 2019 and updated in April 2023 in MEDLINE(PubMed). We included studies on the relationship of environmental heat exposure during pregnancy and any long-term outcomes. Risk of bias was assessed using tools developed by the Joanna-Briggs Institute, and the evidence was appraised using the GRADE approach. Synthesis without Meta-Analysis (SWiM) guidelines were used. RESULTS: Eighteen thousand six hundred twenty one records were screened, with 29 studies included across six outcome groups. Studies were mostly conducted in high-income countries (n = 16/25), in cooler climates. All studies were observational, with 17 cohort, 5 case-control and 8 cross-sectional studies. The timeline of the data is from 1913 to 2019, and individuals ranged in age from neonates to adults, and the elderly. Increasing heat exposure during pregnancy was associated with decreased earnings and lower educational attainment (n = 4/6), as well as worsened cardiovascular (n = 3/6), respiratory (n = 3/3), psychiatric (n = 7/12) and anthropometric (n = 2/2) outcomes, possibly culminating in increased overall mortality (n = 2/3). The effect on female infants was greater than on males in 8 of 9 studies differentiating by sex. The quality of evidence was low in respiratory and longevity outcome groups to very low in all others. CONCLUSIONS: Increasing heat exposure was associated with a multitude of detrimental outcomes across diverse body systems. The biological pathways involved are yet to be elucidated, but could include epigenetic and developmental perturbations, through interactions with the placenta and inflammation. This highlights the need for further research into the long-term effects of heat exposure, biological pathways, and possible adaptation strategies in studies, particularly in neglected regions. Heat exposure in-utero has the potential to compound existing health and social inequalities. Poor study design of the included studies constrains the conclusions of this review, with heterogenous exposure measures and outcomes rendering comparisons across contexts/studies difficult. TRIAL REGISTRATION: PROSPERO CRD 42019140136.

Final 192-Week Efficacy and Safety Results of the ADVANCE Trial, Comparing 3 First-line Antiretroviral Regimens.

Background: ADVANCE compared 3 World Health Organization-recommended first-line regimens in participants with HIV who were antiretroviral naive. Methods: This randomized, open-label, noninferiority trial enrolled participants living with HIV with no antiretroviral exposure in the previous 6 months to 1 of the following arms: tenofovir alafenamide (TAF) / emtricitabine (FTC) + dolutegravir (DTG) (2 tablets), tenofovir disoproxil fumarate (TDF) / FTC + DTG (2 tablets), or a fixed-dose combination of TDF / FTC / efavirenz (EFV) (1 tablet). We report the final safety and efficacy data up to 192 weeks. Results: Repeat consent from the original 351 participants randomized to each arm was obtained from 230 participants (66%) in the TAF/FTC + DTG arm, 209 (60%) in the TDF/FTC + DTG arm, and 183 (52%) in the TDF/FTC/EFV arm. At 192 weeks, 213 (61%) of the original 351 participants in the TAF/FTC + DTG arm, 195 (56%) in the TDF/FTC + DTG arm, and 172 (49%) in the TDF/FTC/EFV arm had confirmed RNA <50 copies/mL, with low virologic failure in all groups and no significant integrase inhibitor mutations in any arm. Mean weight gain was 8.9 kg (SD, 7.1) in the TAF/FTC + DTG arm, 5.9 kg (SD, 7.1) in the TDF/FTC + DTG arm, and 3.2 kg (SD, 8.1) in the TDF/FTC/EFV arm at 192 weeks from baseline and was greatest among women, those taking TAF, and those with lower baseline CD4 counts. The weight trajectory slowed after week 96. There were few clinical events and minor laboratory changes and differences among arms after 96 weeks. There were no significant differences in treatment-emergent hypertension or pregnancy outcomes by arm. Conclusions: High viral suppression was seen across arms, with no resistance to DTG. Weight gain continued but slowed after 96 weeks, with few clinical events or laboratory changes.

Too hot to thrive: a qualitative inquiry of community perspectives on the effect of high ambient temperature on postpartum women and neonates in Kilifi, Kenya.

OBJECTIVE: To understand community perspectives on the effects of high ambient temperature on the health and wellbeing of neonates, and impacts on post-partum women and infant care in Kilifi. DESIGN: Qualitative study using key informant interviews, in-depth interviews and focus group discussions with pregnant and postpartum women (n = 22), mothers-in-law (n = 19), male spouses (n = 20), community health volunteers (CHVs) (n = 22) and stakeholders from health and government ministries (n = 16). SETTINGS: We conducted our research in Kilifi County in Kenya's Coast Province. The area is largely rural and during summer, air temperatures can reach 37˚C and rarely go below 23˚C. DATA ANALYSIS: Data were analyzed in NVivo 12, using both inductive and deductive approaches. RESULTS: High ambient temperature is perceived by community members to have direct and indirect health pathways in pregnancy and postpartum periods, including on the neonates. The direct impacts include injuries on the neonate's skin and in the mouth, leading to discomfort and affecting breastfeeding and sleeping. Participants described babies as "having no peace". Heat effects were perceived to be amplified by indoor air pollution and heat from indoor cooking fires. Community members believed that exclusive breastfeeding was not practical in conditions of extreme heat because it lowered breast milk production, which was, in turn, linked to a low scarcity of food and time spend by mothers away from their neonates performing household chores. Kangaroo Mother Care (KMC) was also negatively affected. Participants reported that postpartum women took longer to heal in the heat, were exhausted most of the time and tended not to attend postnatal care. CONCLUSIONS: High ambient temperatures affect postpartum women and their neonates through direct and indirect pathways. Discomfort makes it difficult for the mother to care for the baby. Multi-sectoral policies and programs are required to mitigate the negative impacts of high ambient temperatures on maternal and neonatal health in rural Kilifi and similar settings.

Protocol of an individual participant data meta-analysis to quantify the impact of high ambient temperatures on maternal and child health in Africa (HE2AT IPD).

INTRODUCTION: Globally, recognition is growing of the harmful impacts of high ambient temperatures (heat) on health in pregnant women and children. There remain, however, major evidence gaps on the extent to which heat increases the risks for adverse health outcomes, and how this varies between settings. Evidence gaps are especially large in Africa. We will conduct an individual participant data (IPD) meta-analysis to quantify the impacts of heat on maternal and child health in sub-Saharan Africa. A detailed understanding and quantification of linkages between heat, and maternal and child health is essential for developing solutions to this critical research and policy area. METHODS AND ANALYSIS: We will use IPD from existing, large, longitudinal trial and cohort studies, on pregnant women and children from sub-Saharan Africa. We will systematically identify eligible studies through a mapping review, searching data repositories, and suggestions from experts. IPD will be acquired from data repositories, or through collaboration with data providers. Existing satellite imagery, climate reanalysis data, and station-based weather observations will be used to quantify weather and environmental exposures. IPD will be recoded and harmonised before being linked with climate, environmental, and socioeconomic data by location and time. Adopting a one-stage and two-stage meta-analysis method, analytical models such as time-to-event analysis, generalised additive models, and machine learning approaches will be employed to quantify associations between exposure to heat and adverse maternal and child health outcomes. ETHICS AND DISSEMINATION: The study has been approved by ethics committees. There is minimal risk to study participants. Participant privacy is protected through the anonymisation of data for analysis, secure data transfer and restricted access. Findings will be disseminated through conferences, journal publications, related policy and research fora, and data may be shared in accordance with data sharing policies of the National Institutes of Health. PROSPERO REGISTRATION NUMBER: CRD42022346068.

A WHO-led global strategy to control greenhouse gas emissions: a call for action.

BACKGROUND: Climate change, driven by anthropogenic greenhouse gas emissions, is among the greatest threats to human health. The World Health Organisation (WHO), has led global efforts to respond to emerging public health threats including the control of hazardous substances such as tobacco, alcohol, lead and asbestos, with remarkable health gains. BODY: Despite WHO's clear messaging on the enormous and growing health risks of climate change, greenhouse gases are not yet classified as hazardous substances, requiring control through a global strategy or framework. Additionally, WHO has not classified disease attributable to climate change as a result of the promulgation of these hazards as a Public Health Emergency of International Concern (PHEIC), despite the serious and preventable health risks it poses globally. Several historical precedents set the stage for WHO to declare excess greenhouse gases as health hazards, including the control of ozone-depleting substances and breast-milk substitutes where the public benefit of control exceeded the potential benefit of their promulgation. In addition, WHO's undertaking within the International Health Regulations to protect global health, providing imperative to declare climate change a PHEIC, with Tedros Adhanom Ghebreyesus, director-general of WHO, declaring: "The climate crisis is a health crisis, fuelling outbreaks, contributing to higher rates of noncommunicable diseases, and threatening to overwhelm our health workforce and health infrastructure". Importantly, the health sector, perhaps more than other sectors, has successfully overcome formidable, vested interests in combatting these threats to health. CONCLUSION: It is thus imperative that WHO make full use of their credibility and influence to establish a global framework for the control of greenhouse gases through the declaration of excess greenhouse gas emissions as a hazardous substance, and declaring climate change a PHEIC. Who else is better placed to drive the considerable societal transformation needed to secure a liveable future?

More Frequent HIV Viral Load Testing With Point-Of-Care Tests Detects Elevated Viral Load Earlier in Postpartum HIV-Positive Women in a Randomized Controlled Trial in Two Clinics in Johannesburg, South Africa.

BACKGROUND: Elevated maternal HIV viral load (VL) increases vertical transmission risk for breastfeeding children. This randomized controlled trial in Johannesburg primarily evaluated whether 3-monthly point-of-care testing, with laboratory-based standard-of-care testing (arm 2), compared with 6-monthly laboratory-based VL testing (arm 1) in postpartum women living with HIV receiving first-line tenofovir-emtricitabine-efavirenz antiretroviral treatment improved VL suppression, factors associated with nonsuppression, and drug resistance in those with virologic failure. METHODS: Mother-child pairs were enrolled July 2018-April 2019 at the child's 6/10/14-week clinic visit. Women were randomized 1:1 to arm 1 or 2. Trained staff performed point-of-care VL testing using the Cepheid's Xpert HIV-1 VL assay. We fitted a generalized linear mixed model with VL suppression (<50 copies/mL (cps/mL) and <1000 cps/mL) at enrollment and 6, 12, and 18 months postpartum as the outcome and indicator variables for time, study site, study arm, and interaction variables. The final model tested for a difference by study arm, pooling across time points. RESULTS: Of 405 women enrolled (204 arm 1 and 201 arm 2), 249 (61%) remained in follow-up through 18 months. There was no difference in VL suppression between arms at 6, 12, or 18 months. VL suppression rate (<50 cps/mL) at 18 months was 64.8% in arm 1 and 63.0% in arm 2 (P = 0.27). On bivariate analysis, there was an association with late antenatal booking and being in arm 2 for nonsuppressed VL, but no significant association with breastfeeding. HIV drug resistance was found in 12 of 23 participants (52.2%). CONCLUSION: We found no significant difference in VL suppression with more frequent VL testing in postpartum women living with HIV receiving first-line efavirenz-based antiretroviral treatment.

Increasing global temperatures threaten gains in maternal and newborn health in Africa: A review of impacts and an adaptation framework.

Anatomical, physiologic, and socio-cultural changes during pregnancy and childbirth increase vulnerability of women and newborns to high ambient temperatures. Extreme heat can overwhelm thermoregulatory mechanisms in pregnant women, especially during labor, cause dehydration and endocrine dysfunction, and compromise placental function. Clinical sequelae include hypertensive disorders, gestational diabetes, preterm birth, and stillbirth. High ambient temperatures increase rates of infections, and affect health worker performance and healthcare seeking. Rising temperatures with climate change and limited resources heighten concerns. We propose an adaptation framework containing four prongs. First, behavioral changes such as reducing workloads during pregnancy and using low-cost water sprays. Second, health system interventions encompassing Early Warning Systems centered around existing community-based outreach; heat-health indicator tracking; water supplementation and monitoring for heat-related conditions during labor. Building modifications, passive and active cooling systems, and nature-based solutions can reduce temperatures in facilities. Lastly, structural interventions and climate financing are critical. The overall package of interventions, ideally selected following cost-effectiveness and thermal modeling trade-offs, needs to be co-designed and co-delivered with affected communities, and take advantage of existing maternal and child health platforms. Robust-applied research will set the stage for programs across Africa that target pregnant women. Adequate research and climate financing are now urgent.

High prevalence of SARS-CoV-2 antibodies in pregnant women after the second wave of infections in the inner-city of Johannesburg, Gauteng Province, South Africa.

OBJECTIVES: After South Africa's second wave of COVID-19, this study estimated the SARS-CoV-2 seroprevalence among pregnant women in inner-city Johannesburg, South Africa. METHODS: In this cross-sectional survey, 500 pregnant women who were non-COVID-19-vaccinated (aged ≥12 years) were enrolled, and demographic and clinical data were collected. Serum samples were tested using the Wantai SARS-CoV-2 spike antibody enzyme-linked immunosorbent assay and Roche Elecsys® anti-SARS-CoV-2 nucleocapsid antibody assays. Seropositivity was defined as SARS-CoV-2 antibodies on either (primary) or both (secondary) assays. Univariate Poisson regression assessed risk factors associated with seropositivity. RESULTS: The median age was 27.4 years, and HIV prevalence was 26.7%. SARS-CoV-2 seroprevalence was 64.0% (95% confidence interval [CI]: 59.6-68.2%) on the primary and 54% (95% CI: 49.5-58.4%) on the secondary measure. Most (96.6%) women who were SARS-CoV-2-seropositive reported no symptoms. On the Roche assay, we detected lower seroprevalence among women living with HIV than women without HIV (48.9% vs 61.7%, P-value = 0.018), and especially low levels among women living with HIV with a clusters of differentiation 4 <350 cells/ml compared with women without immune suppression (22.2% vs 56.4%, prevalence rate ratio = 0.4; 95% CI: 0.2-0.9; P-value = 0.046). CONCLUSION: Pregnant women attending routine antenatal care had a high SARS-CoV-2 seroprevalence after the second wave in South Africa, and most had asymptomatic infections. Seroprevalence surveys in pregnant women present a feasible method of monitoring the course of the pandemic over time.

Differentiated HIV services for transgender people in four South African districts: population characteristics and HIV care cascade.

INTRODUCTION: Transgender people in South Africa are disproportionately affected by HIV, discrimination and stigma. Access to healthcare and health outcomes are poor. Although integrating gender-affirming healthcare with differentiated HIV prevention, care and treatment services has shown improvement in HIV service uptake and health outcomes among transgender people, evidence is lacking on the implementation of differentiated service delivery models in southern Africa. This article describes a differentiated service delivery model across four South African sites and transgender individuals who access these services. We assess whether hormone therapy (HT) is associated with continued use of pre-exposure prophylaxis (PrEP) and viral load suppression. METHODS: In 2019, differentiated healthcare centres for transgender individuals opened in four South African districts, providing gender-affirming healthcare and HIV services at a primary healthcare level. Routine programme data were collected between October 2019 and June 2021. Descriptive statistics summarized patient characteristics and engagement with HIV prevention and treatment services. We conducted a multivariate logistic regression analysis to determine whether HT was associated with viral load suppression and PrEP continued use. RESULTS: In the review period, we reached 5636 transgender individuals through peer outreach services; 86% (4829/5636) of them accepted an HIV test and 62% (3535/5636) were linked to clinical services. Among these, 89% (3130/3535) were transgender women, 5% (192/3535) were transgender men and 6% (213/3535) were gender non-conforming individuals. Of those who received an HIV test, 14% (687/4829) tested positive and 91% of those initiated antiretroviral treatment. Viral load suppression was 75% in this cohort. PrEP was accepted by 28% (1165/4142) of those who tested negative. Five percent (161/3535) reported ever receiving HT through the public healthcare system. Service users who received HT were three-fold more likely to achieve viral load suppression. We did not find any association between HT and continued use of PrEP. CONCLUSIONS: A differentiated HIV and gender-affirming service delivery model at a primary healthcare level is feasible and can enhance service access in South Africa. HT can improve HIV clinical outcomes for transgender people. As trust is established between the providers and population, uptake of HIV testing and related services may increase further.

Public Health Measures to Address the Impact of Climate Change on Population Health-Proceedings from a Stakeholder Workshop.

BACKGROUND: The World Health Organization identified climate change as the 21st century's biggest health threat. This study aimed to identify the current knowledge base, evidence gaps, and implications for climate action and health policymaking to address the health impact of climate change, including in the most underserved groups. METHODS: The Horizon-funded project ENBEL ('Enhancing Belmont Research Action to support EU policy making on climate change and health') organised a workshop at the 2021-European Public Health conference. Following presentations of mitigation and adaptation strategies, seven international researchers and public health experts participated in a panel discussion linking climate change and health. Two researchers transcribed and thematically analysed the panel discussion recording. RESULTS: Four themes were identified: (1) 'Evidence is key' in leading the climate debate, (2) the need for 'messaging about health for policymaking and behaviour change' including health co-benefits of climate action, (3) existing 'inequalities between and within countries', and (4) 'insufficient resources and funding' to implement national health adaptation plans and facilitate evidence generation and climate action, particularly in vulnerable populations. CONCLUSION: More capacity is needed to monitor health effects and inequities, evaluate adaptation and mitigation interventions, address current under-representations of low- or middle-income countries, and translate research into effective policymaking.

How do high ambient temperatures affect infant feeding practices? A prospective cohort study of postpartum women in Bobo-Dioulasso, Burkina Faso.

OBJECTIVE: To examine the effects of high ambient temperature on infant feeding practices and childcare. DESIGN: Secondary analysis of quantitative data from a prospective cohort study. SETTING: Community-based interviews in the commune of Bobo-Dioulasso, Burkina Faso. Exclusive breastfeeding is not widely practised in Burkina Faso. PARTICIPANTS: 866 women (1:1 urban:rural) were interviewed over 12 months. Participants were interviewed at three time points: cohort entry (when between 20 weeks' gestation and 22 weeks' postpartum), three and nine months thereafter. Retention at nine-month follow-up was 90%. Our secondary analysis focused on postpartum women (n=857). EXPOSURE: Daily mean temperature (°C) measured at one weather station in Bobo-Dioulasso. Meteorological data were obtained from publicly available archives (TuTiempo.net). PRIMARY OUTCOME MEASURES: Self-reported time spent breastfeeding (minutes/day), exclusive breastfeeding of infants under 6 months (no fluids other than breast milk provided in past 24 hours), supplementary feeding of infants aged 6-12 months (any fluid other than breast milk provided in past 24 hours), time spent caring for children (minutes/day). RESULTS: The population experienced year-round high temperatures (daily mean temperature range=22.6°C-33.7°C). Breastfeeding decreased by 2.3 minutes/day (95% CI -4.6 to 0.04, p=0.05), and childcare increased by 0.6 minutes/day (0.06 to 1.2, p=0.03), per 1°C increase in same-day mean temperature. Temperature interacted with infant age to affect breastfeeding duration (p=0.02), with a stronger (negative) association between temperature and breastfeeding as infants aged (0-57 weeks). Odds of exclusive breastfeeding very young infants (0-3 months) tended to decrease as temperature increased (OR=0.88, 0.75 to 1.02, p=0.09). There was no association between temperature and exclusive breastfeeding at 3-6 months or supplementary feeding (6-12 months). CONCLUSIONS: Women spent considerably less time breastfeeding (~25 minutes/day) during the hottest, compared with coolest, times of the year. Climate change adaptation plans for health should include advice to breastfeeding mothers during periods of high temperature.

Climate change knowledge, concerns and experiences in secondary school learners in South Africa.

Climate change poses a major threat to the future of today's youth. Globally, young people are at the forefront of climate change activism. Their ability to engage, however, depends on the level of knowledge of climate change and concern about the topic. We sought to examine levels of knowledge and concerns about climate change among youth in South Africa, and their experiences of heat exposure. Ten questions on climate change knowledge, concerns and experiences were nested within a cross-sectional survey conducted in a cluster randomised trial among 924 secondary school learners in 14 public schools in low-income Western Cape areas. Learners' mean age was 15.8 years and they were predominately female. While 72.0% of respondents knew that climate change leads to higher temperatures, only 59.7% agreed that human activity is responsible for climate change, and 58.0% believed that climate change affects human health. Two thirds (68.7%) said that climate change is a serious issue and 65.9% indicated action is needed for prevention. Few learners indicated climate change events had affected them, although many reported difficulties concentrating during hot weather (72.9%). Female learners had lower knowledge levels than male learners, but more frequent heat-related symptoms. Learners scoring high on knowledge questions expressed the most concern about climate change and had the highest heat impacts. Many youth seem unaware that climate change threatens their future. Heat-related symptoms are common, likely undermining educational performance, especially as temperatures escalate. More is needed to mainstream climate change into South African school curricula.

The Effect of High and Low Ambient Temperature on Infant Health: A Systematic Review.

Children, and particularly infants, have physiological, anatomic, and social factors that increase vulnerability to temperature extremes. We performed a systematic review to explore the association between acute adverse infant outcomes (children 0-1 years) and exposure to high and low ambient temperatures. MEDLINE (Pubmed), Embase, CINAHL Plus, and Global Health were searched alongside the reference lists of key papers. We included published journal papers in English that assessed adverse infant outcomes related to short-term weather-related temperature exposure. Twenty-six studies met our inclusion criteria. Outcomes assessed included: infant mortality (n = 9), sudden infant death syndrome (n = 5), hospital visits or admissions (n = 5), infectious disease outcomes (n = 5), and neonatal conditions such as jaundice (n = 2). Higher temperatures were associated with increased risk of acute infant mortality, hospital admissions, and hand, foot, and mouth disease. Several studies identified low temperature impacts on infant mortality and episodes of respiratory disease. Findings on temperature risks for sudden infant death syndrome were inconsistent. Only five studies were conducted in low- or middle-income countries, and evidence on subpopulations and temperature-sensitive infectious diseases was limited. Public health measures are required to reduce the impacts of heat and cold on infant health.

How Climate Change May Threaten Progress in Neonatal Health in the African Region.

Climate change is likely to have wide-ranging impacts on maternal and neonatal health in Africa. Populations in low-resource settings already experience adverse impacts from weather extremes, a high burden of disease from environmental exposures, and limited access to high-quality clinical care. Climate change is already increasing local temperatures. Neonates are at high risk of heat stress and dehydration due to their unique metabolism, physiology, growth, and developmental characteristics. Infants in low-income settings may have little protection against extreme heat due to housing design and limited access to affordable space cooling. Climate change may increase risks to neonatal health from weather disasters, decreasing food security, and facilitating infectious disease transmission. Effective interventions to reduce risks from the heat include health education on heat risks for mothers, caregivers, and clinicians; nature-based solutions to reduce urban heat islands; space cooling in health facilities; and equitable improvements in housing quality and food systems. Reductions in greenhouse gas emissions are essential to reduce the long-term impacts of climate change that will further undermine global health strategies to reduce neonatal mortality.

Ambient temperature during pregnancy and risk of maternal hypertensive disorders: A time-to-event study in Johannesburg, South Africa.

Hypertensive disorders in pregnancy are a leading cause of maternal and perinatal mortality and morbidity. We evaluate the effects of ambient temperature on risk of maternal hypertensive disorders throughout pregnancy. We used birth register data for all singleton births (22-43 weeks' gestation) recorded at a tertiary-level hospital in Johannesburg, South Africa, between July 2017-June 2018. Time-to-event analysis was combined with distributed lag non-linear models to examine the effects of mean weekly temperature, from conception to birth, on risk of (i) high blood pressure, hypertension, or gestational hypertension, and (ii) pre-eclampsia, eclampsia, or HELLP (hemolysis, elevated liver enzymes, low platelets). Low and high temperatures were defined as the 5th and 95th percentiles of daily mean temperature, respectively. Of 7986 women included, 844 (10.6%) had a hypertensive disorder of which 432 (51.2%) had high blood pressure/hypertension/gestational hypertension and 412 (48.8%) had pre-eclampsia/eclampsia/HELLP. High temperature in early pregnancy was associated with an increased risk of pre-eclampsia/eclampsia/HELLP. High temperature (23 °C vs 18 °C) in the third and fourth weeks of pregnancy posed the greatest risk, with hazard ratios of 1.76 (95% CI 1.12-2.78) and 1.79 (95% CI 1.19-2.71), respectively. Whereas, high temperatures in mid-late pregnancy tended to protect against pre-eclampsia/eclampsia/HELLP. Low temperature (11°) during the third trimester (from 29 weeks' gestation) was associated with an increased risk of high blood pressure/hypertension/gestational hypertension, however the strength and statistical significance of low temperature effects were reduced with model adjustments. Our findings support the hypothesis that high temperatures in early pregnancy increase risk of severe hypertensive disorders, likely through an effect on placental development. This highlights the need for greater awareness around the impacts of moderately high temperatures in early pregnancy through targeted advice, and for increased monitoring of pregnant women who conceive during periods of hot weather.

Associations between ambient temperature and risk of preterm birth in Sweden: A comparison of analytical approaches.

BACKGROUND: Evidence indicates that high temperatures are a risk factor for preterm birth. Increasing heat exposures due to climate change are therefore a concern for pregnant women. However, the large heterogeneity of study designs and statistical methods across previous studies complicate interpretation and comparisons. We investigated associations of short-term exposure to high ambient temperature with preterm birth in Sweden, applying three complementary analytical approaches. METHODS: We included 560,615 singleton live births between 2014 and 2019, identified in the Swedish Pregnancy Register. We estimated weekly mean temperatures at 1-km2 spatial resolution using a spatiotemporal machine learning methodology, and assigned them at the residential addresses of the study participants. The main outcomes of the study were gestational age in weeks and subcategories of preterm birth (<37 weeks): extremely preterm birth (<28 weeks), very preterm birth (from week 28 to <32), and moderately preterm birth (from week 32 to<37). Case-crossover, quantile regression and time-to-event analyses were applied to estimate the effects of short-term exposure to increased ambient temperature during the week before birth on preterm births. Furthermore, distributed lag nonlinear models (DLNM) were applied to identify susceptibility windows of exposures throughout pregnancy in relation to preterm birth. RESULTS: A total of 1924 births were extremely preterm (0.4%), 2636 very preterm (0.5%), and 23,664 moderately preterm (4.2%). Consistent across all three analytical approaches (case-crossover, quantile regression and time-to-event analyses), higher ambient temperature (95th vs 50th percentile) demonstrated increased risk of extremely preterm birth, but associations did not reach statistical significance. In DLNM models, we observed no evidence to suggest an increased effect of high temperature on preterm birth risk. Even so, a suggested trend was observed in both the quantile regression and time-to-event analyses of a higher risk of extremely preterm birth with higher temperature during the last week before birth. CONCLUSIONS: In Sweden, with high quality data on exposure and outcome, a temperate climate and good quality ante-natal health care, we did not find an association between high ambient temperatures and preterm births. Results were consistent across three complementary analytical approaches.

The economics of sex work and major sporting events: Learning from the 2010 FIFA World Cup in South Africa.

Risk-taking in sex work is related to financial gains from condom-protected and condomless-acts alongside vulnerabilities, including socio-economic factors, which influence the safety of sex workers. Large international sporting events have been shown to significantly impact the economies of host countries, but there is a dearth of studies that examine how major sporting events may affect the economics of sex work and the risks taken by sex workers and clients. This study examines the determinants of the price of commercial sex alongside the price premium for and correlates of, condomless sex before, during and after the 2010 world cup in South Africa. We analysed data from three phases of repeated cross-sectional surveys with sex workers. Bivariate and multivariable logistic regression models were fitted to examine the predictors of condomless sex. We also fitted fixed-effect regression models to examine the determinants of the price of commercial sex across each survey phase. Findings suggest that the price of sex was higher during the world cup compared to before and after, whilst the price premium for condomless-sex increased from 36% before the world cup to 40% (p-value<0.001) and 57% (p-value<0.001) during and after the world cup, respectively. Across the survey phases, anal, oral or masturbation sex were more likely to be supplied without a condom compared to vaginal sex. The type of sex was the primary determinant of the price of sex across all phases. We show indicative evidence that the 2010 world cup was associated with an increase in the price of sex and supply of condomless-sex. Although these findings should be interpreted as associations rather than causal relationships, we recommend that countries with substantial sex-worker populations that host major events shouldexplicitly consider the context and structures of sex work, and promote client-focused safe-sex-interventions that explicitly consider the economic pressures faced by sexworkers to provide riskier acts, to minimise health impacts.

Physiological mechanisms of the impact of heat during pregnancy and the clinical implications: review of the evidence from an expert group meeting.

Many populations experience high seasonal temperatures. Pregnant women are considered vulnerable to extreme heat because ambient heat exposure has been linked to pregnancy complications including preterm birth and low birthweight. The physiological mechanisms that underpin these associations are poorly understood. We reviewed the existing research evidence to clarify the mechanisms that lead to adverse pregnancy outcomes in order to inform public health actions. A multi-disciplinary expert group met to review the existing evidence base and formulate a consensus regarding the physiological mechanisms that mediate the effect of high ambient temperature on pregnancy. A literature search was conducted in advance of the meeting to identify existing hypotheses and develop a series of questions and themes for discussion. Numerous hypotheses have been generated based on animal models and limited observational studies. There is growing evidence that pregnant women are able to appropriately thermoregulate; however, when exposed to extreme heat, there are a number of processes that may occur which could harm the mother or fetus including a reduction in placental blood flow, dehydration, and an inflammatory response that may trigger preterm birth. There is a lack of substantial evidence regarding the processes that cause heat exposure to harm pregnant women. Research is urgently needed to identify what causes the adverse outcomes in pregnancy related to high ambient temperatures so that the impact of climate change on pregnant women can be mitigated.

HIV Incidence Among Pregnant and Nonpregnant Women in the FACTS-001 Trial: Implications for HIV Prevention, Especially PrEP Use.

BACKGROUND: During pregnancy and postpartum period, the sexual behaviors of women and their partners change in ways that may either increase or reduce HIV risks. Pregnant women are a priority population for reducing both horizontal and vertical HIV transmission. SETTING: Nine sites in 4 South African provinces. METHODS: Women aged 18-30 years were randomized to receive pericoital tenofovir 1% gel or placebo gel and required to use reliable modern contraception. We compared HIV incidence in women before, during, and after pregnancy and used multivariate Cox Proportional hazards models to compare HIV incidence by pregnancy status. RESULTS: Rates of pregnancy were 7.1 per 100 woman-years (95% confidence interval [CI]: 6.3 to 8.1) and highest in those who reported oral contraceptive use (25.1 per 100 woman-years; adjusted hazard ratio 22.97 higher than other women; 95% CI: 5.0 to 105.4) or had 2 children. Birth outcomes were similar between trial arms, with 59.8% having full-term live births. No difference was detected in incident HIV during pregnancy compared with nonpregnant women (2.1 versus 4.3%; hazard ratio = 0.56, 95% CI: 0.14 to 2.26). Sexual activity was low in pregnancy and the early postpartum period, as was consistent condom use. CONCLUSIONS: Pregnancy incidence was high despite trial participation being contingent on contraceptive use. We found no evidence that rates of HIV acquisition were elevated in pregnancy when compared with those in nonpregnant women. Risks from reductions in condom use may be offset by reduced sexual activity. Nevertheless, high HIV incidence in both pregnant and nonpregnant women supports consideration of introducing antiretroviral-containing pre-exposure prophylaxis for pregnant and nonpregnant women in high HIV prevalence settings.