SA-MRC/Wits Agincourt Unit (Research Outputs/Publications)
Permanent URI for this collectionhttps://hdl.handle.net/10539/37309
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Item Mortality in children aged <5 years with severe acute respiratory illness in a high HIVprevalence urban and rural areas of South Africa, 2009–2013(2021-08-12) Oluwatosin A Ayeni; Sibongile Walaza; Stefano Tempia; Michelle Groome; Kathleen Kahn; Shabir A Madhi; Adam L Cohen; Jocelyn Moyes; Marietjie Venter; Marthi Pretorius; Florette Treurnicht; Orienka Hellferscee; Anne von Gottberg; Nicole Wolter; Cheryl CohenBackground: Severe acute respiratory illness (SARI) is an important cause of mortality in young children, especially in children living with HIV infection. Disparities in SARI death in children aged <5 years exist in urban and rural areas. Objective: To compare the factors associated with in-hospital death among children aged <5 years hospitalized with SARI in an urban vs. a rural setting in South Africa from 2009-2013. Methods: Data were collected from hospitalized children with SARI in one urban and two rural sentinel surveillance hospitals. Nasopharyngeal aspirates were tested for ten respiratory viruses and blood for pneumococcal DNA using polymerase chain reaction. We used multivariable logistic regression to identify patient and clinical characteristics associated with in-hospital death. Results: From 2009 through 2013, 5,297 children aged <5 years with SARI-associated hospital admission were enrolled; 3,811 (72%) in the urban and 1,486 (28%) in the rural hospitals. In-hospital case-fatality proportion (CFP) was higher in the rural hospitals (6.9%) than the urban hospital (1.3%, p<0.001), and among HIV-infected than the HIV-uninfected children (9.6% vs. 1.6%, p<0.001). In the urban hospital, HIV infection (odds ratio (OR):11.4, 95% confidence interval (CI):5.4-24.1) and presence of any other underlying illness (OR: 3.0, 95% CI: 1.0-9.2) were the only factors independently associated with death. In the rural hospitals, HIV infection (OR: 4.1, 95% CI: 2.3-7.1) and age <1 year (OR: 3.7, 95% CI: 1.9-7.2) were independently associated with death, whereas duration of hospitalization ≥5 days (OR: 0.5, 95% CI: 0.3-0.8) and any respiratory virus detection (OR: 0.4, 95% CI: 0.3-0.8) were negatively associated with death. Conclusion: We found that the case-fatality proportion was substantially higher among children admitted to rural hospitals and HIV infected children with SARI in South Africa. While efforts to prevent and treat HIV infections in children may reduce SARI deaths, further efforts to address health care inequality in rural populations are needed.Item Human respiratory syncytial virus diversity and epidemiology among patients hospitalized with severe respiratory illness in South Africa, 2012–2015(2015) Ziyaad Valley-Omar; Stefano Tempia; Orienka Hellferscee; Sibongile Walaza; Ebrahim Variava6; Halima Dawood; Kathleen Kahn; Meredith McMorrow; Marthi Pretorius; Senzo Mtshali; Ernest Mamorobela; Nicole Wolter; Marietjie Venter; Anne von Gottberg; Cheryl Cohen; Florette K. TreurnichtBackground: We aimed to describe the prevalence of human respiratory syncytial virus (HRSV) and evaluate associations between HRSV subgroups and/or genotypes and epidemiologic characteristics and clinical outcomes in patients hospitalized with severe respiratory illness (SRI). Methods: Between January 2012 and December 2015, we enrolled patients of all ages admitted to two South African hospitals with SRI in prospective hospital-based syndromic surveillance. We collected respiratory specimens and clinical and epidemiological data. Unconditional random effect multivariable logistic regression was used to assess factors associated with HRSV infection. Results: HRSV was detected in 11.2% (772/6908) of enrolled patients of which 47.0% (363/772) were under the age of 6 months. There were no differences in clinical outcomes of HRSV subgroup A-infected patients compared with HRSV subgroup B-infected patients but among patients aged <5 years, children with HRSV subgroup A were more likely be coinfected with Streptococcus pneumoniae (23/208 11.0% vs. 2/90, 2.0%; adjusted odds ratio 5.7). No significant associations of HRSV A genotypes NA1 and ON1 with specific clinical outcomes were observed. Conclusions: While HRSV subgroup and genotype dominance shifted between seasons, we showed similar genotype diversity as noted worldwide. We found no association between clinical outcomes and HRSV subgroups or genotypes.Item Coronavirus Host Genomics Study: South Africa (COVIGen-SA)(2022-10-06) Andrew K. May; Heather Seymour; Harriet Etheredge; Heather Maher; Marta C. Nunes; ShabirA.Madhi; SimisoM. Sokhela; W. D. FrancoisVenter; Neil Martinson; Firdaus Nabeemeeah; Cheryl Cohen; Jocelyn Moyes; Sibongile Walaza; Stefano Tempia; Jackie Kleynhans; Anne von Gottberg; Jeremy Nel; Halima Dawood; Ebrahim Variava; Stephen Tollman; Kathleen Kahn; KobusHerbst; EmilyB.Wong; CarolineT.Tiemessen; Alex van Blydenstein; Lyle Murray; Michelle Venter; June Fabian; Miche´le RamsayHowever, continental Africans are yet to be adequately represented in such studies despite the importance of genetic factors in understanding Africa’s response to the pandemic. We describe the development of a research resource for coronavirus host genomics studies in South Africa known as COVIGen-SA—a multicollaborator strategic partnership designed to provide harmonised demographic, clinical, and genetic information specific to Black South Africans with COVID-19. Over 2,000 participants have been recruited to date. Preliminary results on 1,354 SARS-CoV-2 positive participants from four participating studies showed that 64.7% were female, 333 had severe disease, and 329 were people living with HIV. *rough this resource, we aim to provide insights into host genetic factors relevant to African-ancestry populations, using both genome-wide association testing and targeted sequencing of important genomic loci. *is project will promote and enhance partnerships, build skills, and develop resources needed to address the COVID-19 burden and associated risk factors in South African communities.Item SARS-CoV-2 Seroprevalence after Third Wave of Infections, South Africa(2022-05) Jackie Kleynhans; Stefano Tempia; Nicole Wolter; Anne von Gottberg; Jinal N. Bhiman; Amelia Buys; Jocelyn Moyes; Meredith L. McMorrow; Kathleen Kahn; F. Xavier Gómez-Olivé; Stephen Tollman; Neil A. Martinson; Floidy Wafawanaka; Limakatso Lebina; Jacques D. du Toit; Waasila Jassat; Mzimasi Neti; Marieke Brauer; Cheryl CohenBy November 2021, after the third wave of severe acute respiratory syndrome coronavirus 2 infections in South Africa, seroprevalence was 60% in a rural community and 70% in an urban community. High seroprevalence before the Omicron variant emerged may have contributed to reduced illness severity observed in the fourth wave.Item COVID-19 vaccine hesitancy in rural South Africa: Deepening understanding to increase uptake and access(2022-05-22) Kathleen Kahn; Audrey Pettifor; Palesa Mataboge; Nicole K Kelly; Duduzile P Mashinini; Harish Nair; Harry Campbell; Cheryl Cohen; F Xavier Gómez-Olivé; Stephen TollmanBackground: To date, COVID-19 vaccine coverage in the African region falls far too short of global goals. Increasing vaccination rates requires understanding barriers to vaccination so that effective interventions that sensitively and effectively address barriers to vaccination can be implemented. Methods: To assess COVID-19 vaccination levels and identify major barriers to vaccine uptake we conducted a population-based, cross-sectional survey among 1662 adults 18 and older from August 25 to October 29 2021 in the Agincourt Health and Socio-Demographic Surveillance System (AHDSS) area, Mpumalanga, South Africa. Results: Half of participants reported receiving a COVID-19 vaccine (50.4%) with 41.1% being fully vaccinated and 9.3% being partially vaccinated; 49.6% were unvaccinated. More women than men were vaccinated (55.5% vs 42.8%, P < 0.001), and older age groups were more likely to be vaccinated than younger age groups (P < 0.001). Among the unvaccinated, 69.0% planned to get vaccinated as soon as possible, while 14.7% reported definitely not wanting the vaccine. Major barriers to vaccination included lacking information on eligibility (12.3%) or where to get vaccinated (13.0%), concerns about side effects (12.5%), and inconvenient hours and locations for vaccination (11.0%). Confidence in the safety and efficacy of COVID-19 vaccines was higher among those vaccinated than unvaccinated (75.3% vs 51.2%, 75.8% vs 51.0%, both P < 0.001, respectively). Conclusions: Increasing vaccination in South Africa beyond current levels will require a concerted effort to address concerns around vaccine safety and increase confidence in vaccine efficacy. Clarifying eligibility and ensuring access to vaccines at times and places that are convenient to younger populations, men, and other vulnerable groups is necessary.Item SARS-CoV-2 incidence, transmission and reinfection in a rural and an urban setting: results of the PHIRST-C cohort study, South Africa, 2020-2021(2021-12-04) Cheryl Cohen; Jackie Kleynhans; Anne von Gottberg; Meredith L McMorrow; Nicole Wolter; Jinal N Bhiman; Jocelyn Moyes; Jacques du Toit; Mignon du Plessis; Francesc Xavier Gómez-Olivé; Fatimah S Dawood; Thulisa Mkhencele; Kaiyun Sun; Cécile Viboud; Maimuna Carrim; Amelia Buys; Neil A Martinson; Kathleen Kahn; Stephen Tollman; Limakatso Lebina; Floi WafawanakaBackground: By August 2021, South Africa experienced three SARS-CoV-2 waves; the second and third associated with emergence of Beta and Delta variants respectively. Methods: We conducted a prospective cohort study during July 2020-August 2021 in one rural and one urban community. Mid-turbinate nasal swabs were collected twice-weekly from household members irrespective of symptoms and tested for SARS-CoV-2 using real-time reverse transcription polymerase chain reaction (rRT-PCR). Serum was collected every two months and tested for anti-SARS-CoV-2 antibodies. Results: Among 115,759 nasal specimens from 1,200 members (follow-up rate 93%), 1976 (2%) were SARS-CoV-2-positive. By rRT-PCR and serology combined, 62% (749/1200) of individuals experienced ≥1 SARS-CoV-2 infection episode, and 12% (87/749) experienced reinfection. Of 662 PCR-confirmed episodes with available data, 15% (n=97) were associated with ≥1 symptom. Among 222 households, 200 (90%) had ≥1 SARS-CoV-2-positive individual. Household cumulative infection risk (HCIR) was 25% (213/856). On multivariable analysis, accounting for age and sex, index case lower cycle threshold value (OR 3.9, 95%CI 1.7-8.8), urban community (OR 2.0,95%CI 1.1-3.9), Beta (OR 4.2, 95%CI 1.7-10.1) and Delta (OR 14.6, 95%CI 5.7-37.5) variant infection were associated with increased HCIR. HCIR was similar for symptomatic (21/110, 19%) and asymptomatic (195/775, 25%) index cases (p=0.165). Attack rates were highest in individuals aged 13-18 years and individuals in this age group were more likely to experience repeat infections and to acquire SARS-CoV-2 infection. People living with HIV who were not virally supressed were more likely to develop symptomatic illness, and shed SARS-CoV-2 for longer compared to HIV-uninfected individuals. Conclusions: In this study, 85% of SARS-CoV-2 infections were asymptomatic and index case symptom status did not affect HCIR, suggesting a limited role for control measures targeting symptomatic individuals. Increased household transmission of Beta and Delta variants, likely contributed to successive waves, with >60% of individuals infected by the end of follow-up.Item The economic burden of RSV-associated illness in children aged < 5 years, South Africa 2011–2016.(2022-06-21) Jocelyn Moyes; Stefano Tempia; Sibongile Walaza; Meredith L. McMorrow3; Florette Treurnicht4 Nicole Wolter; Anne von Gottberg; Kathleen Kahn6; Adam L Cohen; Halima Dawood; Ebrahim Variava; Cheryl CohenIntroduction Data on the economic burden of RSV-associated illness will inform decisions on the programmatic implementation of maternal vaccines and monoclonal antibodies. We estimated these costs in fine age bands to allow more accurate cost-effectiveness models to account for limited duration of protection conferred by short or long acting interventions. Methods We conducted a costing study at sentinel sites across South Africa to estimate out-of-pocket and indirect costs for RSV-associated mild and severe illness. We collected facility-specific costs for staffing, equipment, services, diagnostic tests and treatment. Using case-based data we calculated a patient day equivalent (PDE) for RSV-associated hospitalisations or clinic visits; the PDE was multiplied by the number of days of care to provide a case-cost to the healthcare system. We estimated the costs in 3-month age intervals in children aged <1 years and as a single group for children aged 1-4 years. We then applied our data to a modified version of the World Health Organization tool for estimating mean annual national cost burden, including medically and non-medically attended RSV-associated illness. Results The estimated mean annual cost of RSV-associated Illness in children aged <5 years was United States dollars ($)137 204 393, of which 81% ($111 742 713) were healthcare system incurred, 6% ($8 881 612) were out of pocket expenses and 13% ($28 225 801) were indirect costs. Thirty-three percent ($45 652 677/$137 204 393) of the total cost in children aged <5 years was in the <3-month age group, of which 52% ($71 654 002) were healthcare system incurred. The costs of non-medically attended cases increased with age from $3 307 218 in the <3-month age group to $8 603 377 in the 9-11-month age group. Conclusion Among children <5 years of age with RSV in South Africa, the highest cost burden was in young infants; therefore, interventions against RSV targeting this age group are important to reduce the health and cost burden of RSV-associated illness.Item The attributable fraction of respiratory syncytial virus among patients of different age with influenza-like illness and severe acute respiratory illness in a high HIV prevalence setting, South Africa, 2012-2016 Running title: The attributable fraction of RSV in South Africa (all ages), South Africa 2012- 2016(2022-11-22) Jocelyn Moyes; Stefano Tempia; Sibongile Walaza; Meredith L. McMorrow; Adam L. Cohen; Florette Treurnicht; Orienka Hellferscee; Nicole Wolter; Anne Von Gottberg; Halima Dawood; Ebrahim Variava; Kathleen Kahn; Shabir A. Madhi; Cheryl CohenIntroduction The detection of respiratory syncytial virus (RSV) in upper airway samples does not necessarily infer causality of illness. Calculating the attributable fraction (AF) of RSV in clinical syndromes could refine disease burden estimates. Methods Using unconditional logistic regression models, we estimated the AF of RSV-associated influenza-like illness (ILI) and severe-acute respiratory illness (SARI) cases by comparing RSVdetection prevalence among ILI and SARI cases to those of healthy controls in South Africa, 2012-2016. The analysis, stratified by HIV serostatus, was conducted in the age categories <1, 1-4, 5-24, 25-44, 45-64, ≥65 years. Results We included 12,048 individuals: 2,687 controls, 5,449 ILI cases and 5,449 SARI cases. RSVAFs for ILI were significant in <1, 1-4, 5-24, 25-44-year age groups: 84.9%(95% confidence interval (CI) 69.3%-92.6%), 74.6%(95%CI 53.6%-86.0%), 60.8%(95%CI 21.4%-80.5%) and 64.1%(95%CI 14.9%-84.9%), respectively. Similarly, significant RSV-AFs for SARI were 95.3%(95%CI 91.1%-97.5) and 83.4%(95%CI 70.9-90.5) in the <1 and 1-4-year age groups respectively. In HIV-infected persons, RSV was significantly associated with ILI cases versus controls in individuals aged 5-44 years. Conclusion High RSV-AFs in young children confirm RSV detection is associated severe respiratory illness in South African children, specifically infants. These estimates will assist with refining burden estimates and cost effectiveness modelsItem Incidence and Transmission Dynamics of Bordetella pertussis Infection in Rural and Urban Communities, South Africa, 2016‒2018(2023-02-02) Fahima Moosa; Stefano Tempia; Jackie Kleynhans; Meredith McMorrow; Jocelyn Moyes; Mignon du Plessis; Maimuna Carrim; Florette K. Treurnicht; Orienka Helfersee; Thulisa Mkhencele; Azwifarwi Mathunjwa; Neil A. Martinson; Kathleen Kahn; Limakatso Lebina; Floidy Wafawanaka; Cheryl Cohen; Anne von Gottberg; Nicole WolterWe conducted 3 prospective cohort studies (2016–2018), enrolling persons from 2 communities in South Africa. Nasopharyngeal swab specimens were collected twice a week from participants. Factors associated with Bordetella pertussis incidence, episode duration, and household transmission were determined by using Poisson regression, Weibull accelerated time-failure, and logistic regression hierarchical models, respectively. Among 1,684 participants, 118 episodes of infection were detected in 107 participants (incidence 0.21, 95% CI 0.17–0.25 infections/100 person-weeks). Children <5 years of age who had incomplete vaccination were more likely to have pertussis infection. Episode duration was longer for participants who had higher bacterial loads. Transmission was more likely to occur from male index case-patients and persons who had >7 days infection duration. In both communities, there was high incidence of B. pertussis infection and most cases were colonized.Item Unmasking Pneumococcal Carriage in a High Human Immunodeficiency Virus (HIV) Prevalence Population in two Community Cohorts in South Africa, 2016–2018: The PHIRST Study(2022-07-19) Maimuna Carrim; Stefano Tempia; Deus Thindwa; Neil A Martinson; Kathleen Kahn; Stefan Flasche; Orienka Hellferscee; Florette K Treurnicht; Meredith L McMorrow; Jocelyn Moyes; Thulisa Mkhencele; Azwifarwi Mathunjwa; Jackie Kleynhans; Limakatso Lebina; Katlego Mothlaoleng; Floidy Wafawanaka; Francesc Xavier Gómez-Olivé; Cheryl Cohen; Anne von Gottberg; Nicole WolterBackground Longitudinal pneumococcus colonization data in high human immunodeficiency virus (HIV) prevalence settings following pneumococcal conjugate vaccine introduction are limited. Methods In 327 randomly selected households, 1684 individuals were enrolled and followed-up for 6 to 10 months during 2016 through 2018 from 2 communities. Nasopharyngeal swabs were collected twice weekly and tested for pneumococcus using quantitative lytA real-time polymerase chain reaction. A Markov model was fitted to the data to define the start and end of an episode of colonization. We assessed factors associated with colonization using logistic regression. Results During the study period, 98% (1655/1684) of participants were colonized with pneumococcus at least once. Younger age (<5 years: adjusted odds ratio [aOR], 14.1; 95% confidence [CI], 1.8–111.3, and 5–24 years: aOR, 4.8, 95% CI, 1.9–11.9, compared with 25–44 years) and HIV infection (aOR, 10.1; 95% CI, 1.3–77.1) were associated with increased odds of colonization. Children aged <5 years had fewer colonization episodes (median, 9) than individuals ≥5 years (median, 18; P < .001) but had a longer episode duration (<5 years: 35.5 days; interquartile range, 17–88) vs. ≥5 years: 5.5 days (4–12). High pneumococcal loads were associated with age (<1 year: aOR 25.4; 95% CI, 7.4–87.6; 1–4 years: aOR 13.5, 95% CI 8.3–22.9; 5–14 years: aOR 3.1, 95% CI, 2.1–4.4 vs. 45–65 year old patients) and HIV infection (aOR 1.7; 95% CI 1.2–2.4). Conclusions We observed high levels of pneumococcus colonization across all age groups. Children and people with HIV were more likely to be colonized and had higher pneumococcal loads. Carriage duration decreased with age highlighting that children remain important in pneumococcal transmission.