Browsing by Author "Phillips, Andrew"

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    A quantitative assessment of the consistency of projections from five mathematical models of the HIV epidemic in South Africa: a model comparison study
    (2023-10-27) Moolla, Haroon; Phillips, Andrew; ten Brink, Debra; Mudimu, Edinah; Stover, John; Bansi-Matharu, Loveleen; Martin-Hughes, Rowan; Wulan, Nisaa; Cambiano, Valentina; Smith, Jennifer; Bershteyn, Anna; Meyer-Rath, Gesine; Jamieson, Lise; Johnson, Leigh F.
    Abstract Background Mathematical models are increasingly used to inform HIV policy and planning. Comparing estimates obtained using different mathematical models can test the robustness of estimates and highlight research gaps. As part of a larger project aiming to determine the optimal allocation of funding for HIV services, in this study we compare projections from five mathematical models of the HIV epidemic in South Africa: EMOD-HIV, Goals, HIV-Synthesis, Optima, and Thembisa. Methods The five modelling groups produced estimates of the total population, HIV incidence, HIV prevalence, proportion of people living with HIV who are diagnosed, ART coverage, proportion of those on ART who are virally suppressed, AIDS-related deaths, total deaths, and the proportion of adult males who are circumcised. Estimates were made under a “status quo” scenario for the period 1990 to 2040. For each output variable we assessed the consistency of model estimates by calculating the coefficient of variation and examining the trend over time. Results For most outputs there was significant inter-model variability between 1990 and 2005, when limited data was available for calibration, good consistency from 2005 to 2025, and increasing variability towards the end of the projection period. Estimates of HIV incidence, deaths in people living with HIV, and total deaths displayed the largest long-term variability, with standard deviations between 35 and 65% of the cross-model means. Despite this variability, all models predicted a gradual decline in HIV incidence in the long-term. Projections related to the UNAIDS 95–95-95 targets were more consistent, with the coefficients of variation below 0.1 for all groups except children. Conclusions While models produced consistent estimates for several outputs, there are areas of variability that should be investigated. This is important if projections are to be used in subsequent cost-effectiveness studies.
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    Effects of the COVID-19 pandemic on the outcomes of HIV-exposed neonates: a Zimbabwean tertiary hospital experience
    (BioMed Central, 2024-01-05) Gannon, Hannah; Chappell, Elizabeth; Ford, Deborah; Gibb, Diana M.; Chimwaza, Anesu; Manika, Ngoni; Wedderburn, Catherine J.; Nenguke, Zivai M.; Cowan, Frances M.; Gibb, Tom; Phillips, Andrew; Mushavi, Angela; Fitzgerald, Felicity; Heys, Michelle; Chimhuya, Simbarashe; Bwakura-Dangarembizi, Mutsa
    Abstract Introduction The COVID-19 pandemic has globally impacted health service access, delivery and resources. There are limited data regarding the impact on the prevention of mother to child transmission (PMTCT) service delivery in low-resource settings. Neotree ( www.neotree.org ) combines data collection, clinical decision support and education to improve care for neonates. Here we evaluate impacts of COVID-19 on care for HIV-exposed neonates. Methods Data on HIV-exposed neonates admitted to the neonatal unit (NNU) at Sally Mugabe Central Hospital, Zimbabwe, between 01/06/2019 and 31/12/2021 were analysed, with pandemic start defined as 21/03/2020 and periods of industrial action (doctors (September 2019-January 2020) and nurses (June 2020-September 2020)) included, resulting in modelling during six time periods: pre-doctors’ strike (baseline); doctors’ strike; post-doctors’ strike and pre-COVID; COVID and pre-nurses’ strike; nurses’ strike; post nurses’ strike. Interrupted time series models were used to explore changes in indicators over time. Results Of 8,333 neonates admitted to the NNU, 904 (11%) were HIV-exposed. Mothers of 706/765 (92%) HIV-exposed neonates reported receipt of antiretroviral therapy (ART) during pregnancy. Compared to the baseline period when average admissions were 78 per week (95% confidence interval (CI) 70–87), significantly fewer neonates were admitted during all subsequent periods until after the nurses’ strike, with the lowest average number during the nurses’ strike (28, 95% CI 23–34, p < 0.001). Across all time periods excluding the nurses strike, average mortality was 20% (95% CI 18–21), but rose to 34% (95% CI 25, 46) during the nurses’ strike. There was no evidence for heterogeneity (p > 0.22) in numbers of admissions or mortality by HIV exposure status. Fewer HIV-exposed neonates received a PCR test during the pandemic (23%) compared to the pre-pandemic periods (40%) (RR 0.59, 95% CI 0.41–0.84, p < 0.001). The proportion of HIV-exposed neonates who received antiretroviral prophylaxis during admission was high throughout, averaging between 84% and 95% in each time-period. Conclusion While antiretroviral prophylaxis for HIV-exposed neonates remained high throughout, concerning data on low admissions and increased mortality, similar in HIV-exposed and unexposed neonates, and reduced HIV testing, suggest some aspects of care may have been compromised due to indirect effects of the pandemic.