Malaria hospitalisation among children in Kilifi fall to near zero, research reveals.

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Children's malaria hospitalisation in Kilifi has dropped to near-zero in the last three decades, a study published by a Malaria Journal last month has revealed.

The study covers the last 35 years of clinical surveillance of paediatric malaria admissions in Kilifi in the longest continuous record of severe malaria surveillance anywhere in Africa, according to the researchers.

It tracked 69,165 paediatric admissions to Kilifi County Hospital between January 1990 and December 2024, drawing on children aged 1 month to 14 years who lived in the rural parts of the county.

The study, led by Dr Alice Kamau of the KEMRI-Wellcome Trust Research Programme and Professor Robert Snow of the University of Oxford, estimated malaria exposure using infection prevalence among children admitted for trauma, elective surgery, bites and neoplasms.

"We wanted to understand how malaria has changed over a long period of time. Kilifi gave us a unique opportunity because we have been following children continuously for more than 35 years," said Dr Kamau, the lead author.

The study revealed that in 1999, at the peak of the epidemic, malaria admissions reached 25.5 per cent per 1,000 children, annually and accounted for 53 per cent of all paediatric admissions that year.

By 2020–2024, that rate had collapsed to just 0.65 per 1,000 children per year, a decline the authors describe in the paper as bringing hospital admission with malaria among children in Kilifi to a point where it is "now uncommon."

The study results also reveal that overall community malaria prevalence declined from 35 per cent in the 1990s to 2 per cent in 2020–2024.

Between 2021 and 2024, the hospital recorded only 23 to 53 malaria admissions a year, accounting for less than five per cent of all paediatric admissions, a dramatic shift from the 1990s and early 2000s, when malaria made up more than 40 per cent of the children's ward.

Further,  cerebral malaria became proportionally more common than severe anaemia over time, even as the absolute number of both has fallen sharply. The ratio of cerebral malaria cases to severe anaemia cases rose from 0.33 before 2006 to 2.2 in the most recent period studied.

"As malaria transmission has fallen, young children are exposed much less often. They therefore have less opportunity to develop the partial immunity that comes with repeated exposure, so when they do get malaria, severe disease can occur at older ages. But importantly, we did not see the disease being shifted to older children; the overall burden of severe malaria continued to fall," Dr Kamau said.

The study also found that malaria-specific deaths among hospitalised children fell from 0.43 per 1,000 children annually between 1990 and 1996 to just 0.03 per 1,000 in 2020–2024, a 93 per cent drop.

''Among children admitted with a malaria diagnosis, 617 (2.9 per cent) died before discharge. ''Read part of the study.

The study also shows that transmission intensity and rates of malaria hospitalisation declined, with the median age of malaria hospitalisation raised from 19 months between 1990 and 1996 to 48 months between 2012 and 2019.

Children born within Kilifi today face a lower risk of malaria infection compared to those born during the 1990s. The annual burden of hospitalised paediatric malaria at Kilifi referral hospital has fallen over the years from thousands of cases to fewer than 100 per year.

Community-level transmission also fell just sharply. Researchers estimated malaria exposure in the surrounding population by testing children admitted for unrelated reasons such as trauma, elective surgery, or animal bites for malaria parasites in their blood.

The researchers point to two interventions as most likely responsible for the transformation: sustained coverage of long-lasting insecticide-treated bed nets and improved access to effective first-line treatment, particularly artemether-lumefantrine, which replaced older, failing drugs like chloroquine and sulfadoxine-pyrimethamine over the study period.