Malaria hospitalisation in East Africa: age, phenotype and transmission intensity
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
BMC medicine
Abstract
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.
Description
Keywords
Malaria, Age pattern, Parasite prevalence, Severe malaria, Anaemia, Cerebral malaria
Citation
Kamau, A., Paton, R. S., Akech, S., Mpimbaza, A., Khazenzi, C., Ogero, M., ... & Snow, R. W. (2022). Malaria hospitalisation in East Africa: age, phenotype and transmission intensity. BMC medicine, 20(1), 1-12. https://doi.org/10.1186/s12916-021-02224-w