Browsing by Author "Gupta, Sunetra"

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    Application of sero- epidemiology data to inform interventions for HBV in Africa: should diagnosis and treatment replace catch-up vaccination?
    (Global Health, 2018) McNaughton, Anna L.; Lourenço, José; Armand Bester, Phillip; Mokaya, Jolynne; Lumley, Sheila F.; Forde, Donall; Maponga, Tongai G.; Katumba, Kenneth R.; Goedhals, Dominique; Gupta, Sunetra; Seeley, Janet; Newton, Robert; Ocama, Ponsiano; Matthews, Philippa C.
    International goals for hepatitis B virus (HBV) infection set ambitious targets for elimination by 2030. In populations with a high prevalence of infection, catch-up HBV vaccination of adults is sometimes deployed. An alternative approach of ‘test and treat’ could be applied as a population intervention for HBV. Methods: We used a systematic approach to determine the relationship between prevalence of HBV infection (HBsAg) and exposure (anti-HBc) in Africa. We applied a mathematical model to compare the impact of catch-up vaccination with a ‘test and treat’ strategy in a high prevalence setting. Findings: There is a strong relationship between the prevalence of HBsAg and anti- HBc (p<0·0001) across Africa, but the pattern differs between regions. Our data can be interactively visualised at https://hbv-geo.shinyapps.io/oxafricahbv/. In settings with high prevalence of infection, catch-up vaccination may have a transient effect. However, this intervention does not contribute to a sustained decline in prevalence, because a high proportion of adults are either already infected or immune as a result of prior exposure. In contrast, diagnosing and treating infection has a marked impact on reducing prevalence, equivalent to that of neonatal vaccination. Interpretation: We have developed a high-resolution picture of HBV epidemiology across Africa. In combination with robust neonatal vaccination programmes, testing and treating infection is likely to be of more benefit than catch-up vaccination. This alternative not only benefits the infected individual, but also has impact on transmission, thus contributing to sustained reductions in population prevalence.
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    Malaria hospitalisation in East Africa: age, phenotype and transmission intensity
    (BMC medicine, 2022) Kamau, Alice; Paton, Robert S.; Akech, Samuel; Mpimbaza, Arthur; Khazenzi, Cynthia; Ogero, Morris; Mumo, Eda; Alegana, Victor A.; Agweyu, Ambrose; Mturi, Neema; Mohammed, Shebe; Bigogo, Godfrey; Audi, Allan; Kapisi, James; Sserwanga, Asadu; Namuganga, Jane F.; Kariuki, Simon; Otieno, Nancy A.; Nyawanda, Bryan O.; Olotu, Ally; Salim, Nahya; Athuman, Thabit; Abdulla, Salim; Mohamed, Amina F.; Mtove, George; Reyburn, Hugh; Gupta, Sunetra; Lourenço, José; Bejon, Philip; Snow, Robert W.
    Understanding the age patterns of disease is necessary to target interventions to maximise costeffective impact. New malaria chemoprevention and vaccine initiatives target young children attending routine immunisation services. Here we explore the relationships between age and severity of malaria hospitalisation versus malaria transmission intensity. Methods: Clinical data from 21 surveillance hospitals in East Africa were reviewed. Malaria admissions aged 1 month to 14 years from discrete administrative areas since 2006 were identified. Each site-time period was matched to a model estimated community-based age-corrected parasite prevalence to provide predictions of prevalence in childhood (PfPR2–10). Admission with all-cause malaria, severe malaria anaemia (SMA), respiratory distress (RD) and cerebral malaria (CM) were analysed as means and predicted probabilities from Bayesian generalised mixed models. Results: 52,684 malaria admissions aged 1 month to 14 years were described at 21 hospitals from 49 site-time locations where PfPR2–10 varied from < 1 to 48.7%. Twelve site-time periods were described as low transmission (PfPR2–10 < 5%), five low-moderate transmission (PfPR2–10 5–9%), 20 moderate transmission (PfPR2–10 10–29%) and 12 high transmission (PfPR2–10 ≥ 30%). The majority of malaria admissions were below 5 years of age (69–85%) and rare among children aged 10–14 years (0.7–5.4%) across all transmission settings. The mean age of all-cause malaria hospitalisation was 49.5 months (95% CI 45.1, 55.4) under low transmission compared with 34.1 months (95% CI 30.4, 38.3) at high transmission, with similar trends for each severe malaria phenotype. CM presented among older children at a mean of 48.7 months compared with 39.0 months and 33.7 months for SMA and RD, respectively. In moderate and high transmission settings, 34% and 42% of the children were aged between 2 and 23 months and so within the age range targeted by chemoprevention or vaccines. Conclusions: Targeting chemoprevention or vaccination programmes to areas where community-based parasite prevalence is ≥10% is likely to match the age ranges covered by interventions (e.g. intermittent presumptive treatment in infancy to children aged 2–23 months and current vaccine age eligibility and duration of efficacy) and the age ranges of highest disease burden.