Malaria Cases in Western Kenya Drop 34% After New Vaccine Campaign

Malaria cases across the Lake Victoria basin and Western Kenya's highland-fringe counties have dropped by 34 per cent in the twelve months to June 2026, according to data from the Kenya National Malaria Programme. Health officials attribute the decline primarily to the scaled rollout of the R21/Matrix-M malaria vaccine developed by the University of Oxford and the Serum Institute of India, which Kenya was among the first countries globally to adopt at mass scale.

The campaign, which ran from September 2025 through March 2026, delivered 1.27 million vaccine doses to children aged six months to five years across Kisumu, Siaya, Homabay, Migori, Busia, Kakamega, and Vihiga counties. It was coordinated by the Ministry of Health in partnership with the World Health Organisation, UNICEF, and Gavi, the Vaccine Alliance. The four-dose schedule was administered through a combination of county health facilities and mobile outreach posts.

Why Western Kenya Was the Priority Target

Western Kenya accounts for roughly 40 per cent of all malaria cases nationally despite comprising only 17 per cent of the country's population. The region's proximity to Lake Victoria creates ideal breeding conditions for the Anopheles gambiae mosquito, and rainfall patterns intensified by El Nino events in 2023 and 2024 extended the transmission season significantly. Health workers reported overwhelmed paediatric wards in Kisumu County Referral Hospital during the 2024 peak season, with bed occupancy in malaria wards reaching 178 per cent at one point.

"We had children sleeping on the floor. Families were buying quinine on the street because we had run out. That was the reality before this campaign," said Dr Fredrick Ochieng, a paediatric officer at Jaramogi Oginga Odinga Teaching and Referral Hospital in Kisumu. "The change since the vaccine rollout has been remarkable. Our admissions are down and our severe malaria cases are down even more steeply."

National Malaria Programme Director Dr Wycliffe Sande said severe malaria cases — those requiring hospitalisation and intravenous artemisinin — had fallen by 51 per cent in vaccinated cohorts, a figure that exceeds the efficacy rates observed in clinical trials. He attributed the stronger-than-expected results to simultaneous improvements in insecticide-treated net distribution and indoor residual spraying coverage in the region.

A Model for the Continent

The Kenyan campaign is being closely watched by the African Union's Africa Centres for Disease Control and Prevention as a potential blueprint for continental malaria elimination. Rwanda and Uganda have sent technical delegations to observe Kenya's cold chain management system, which relies partly on Safaricom's rural 5G network to track vaccine inventory in real time, ensuring minimal wastage at the last mile.

Gavi Board Chair Dr Ngozi Okonjo-Iweala praised the campaign in a statement last month, noting that Kenya had achieved a 94 per cent first-dose uptake rate, among the highest for any new vaccine introduction in sub-Saharan Africa. Community health promoters, whose numbers were expanded under the government's universal health coverage programme, were credited with reducing vaccine hesitancy through door-to-door sensitisation.

For parents in the affected counties, the change has been palpable. Adhiambo Otieno, a mother of three in Siaya County, said she lost her first child to severe malaria in 2019. "My youngest two have been vaccinated and they have not had malaria once. That is something I could not have imagined a few years ago," she said. The Ministry of Health plans to extend the R21 vaccination programme to the coastal malaria belt — covering Kwale, Kilifi, and Taita-Taveta — in the next campaign cycle beginning October 2026.