20 August 2021 Vol 373, Issue 6557
Malaria infection and severe disease risks in Africa
By Robert S. Paton, Alice Kamau, Samuel Akech, Ambrose Agweyu, Morris Ogero, Charles Mwandawiro, Neema Mturi, Shebe Mohammed, Arthur Mpimbaza, Simon Kariuki, Nancy A. Otieno, Bryan O. Nyawanda, Amina F. Mohamed, George Mtove, Hugh Reyburn, Sunetra Gupta, Philip Bejon, José Lourenço, Robert W. Snow
Science20 Aug 2021 : 926-931 Full Access
Understanding how changes in community parasite prevalence alter the rate and age distribution of severe malaria is essential for optimizing control efforts. Paton et al. assessed the incidence of pediatric severe malaria admissions from 13 hospitals in East Africa from 2006 to 2020 (see the Perspective by Taylor and Slutsker). Each 25% increase in community parasite prevalence shifted hospital admissions toward younger children. Low rates of lifetime infections appeared to confer some immunity to severe malaria in very young children. Children under the age of 5 years thus need to remain a focus of disease prevention for malaria control.
The relationship between community prevalence of Plasmodium falciparum and the burden of severe, life-threatening disease remains poorly defined. To examine the three most common severe malaria phenotypes from catchment populations across East Africa, we assembled a dataset of 6506 hospital admissions for malaria in children aged 3 months to 9 years from 2006 to 2020. Admissions were paired with data from community parasite infection surveys. A Bayesian procedure was used to calibrate uncertainties in exposure (parasite prevalence) and outcomes (severe malaria phenotypes). Each 25% increase in prevalence conferred a doubling of severe malaria admission rates. Severe malaria remains a burden predominantly among young children (3 to 59 months) across a wide range of community prevalence typical of East Africa. This study offers a quantitative framework for linking malaria parasite prevalence and severe disease outcomes in children.