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Julien Lanoo
Innovative housing designs that lower indoor temperatures and improve ventilation can help reduce the burden of infectious disease in sub-Saharan Africa, particularly as rising temperatures increase health risks in many regions. The findings, published in Nature Medicine, are based on a large cluster randomised trial of modified homes in rural Tanzania, highlighting the potential for low-cost, scalable housing improvements to improve health outcomes in high-risk settings.
After three years, the trial found substantial reductions in key childhood illnesses, including a 44% reduction in malaria, 30% reduction in diarrhoeal disease and 18% reduction in respiratory infections among households living in improved ‘Star homes’, designed to enhance ventilation and reduce indoor temperatures. Children under five living in Star homes were also taller for their age than those in traditional homes, suggesting broader improvements in child health.
“The Star Homes study clearly shows how improvements in house design – such as double-story buildings, cross-ventilation, mosquito screening, self-closing doors, clean water harvesting, improved pit latrines and improved cooking stoves – can make a major health impact by protecting children from malaria, diarrhoea and acute respiratory infections, the major causes of mortality in young children in sub-Saharan Africa,” said Prof Lorenz von Seidlein, of the Mahidol-Oxford Tropical Medicine Research Unit (MORU) in Bangkok and the University of Oxford.
Funded by the Hanako Foundation (Singapore) and developed through a long-established partnership between CSK Research Solutions (Tanzania), the Royal Danish Academy of Architecture and MORU (Thailand), Star Homes was a three-year cluster randomized controlled trial where households with children under 13 years of age in the Mtwara region in southern Tanzania, an area with a high malaria prevalence and high coverage of insecticide-treated nets, were randomly allocated to living in 110 Star Homes or in 513 traditional mud and thatched-roofed houses.
Malaria, diarrhoeal diseases and ARIs are three major causes of mortality in young children in sub-Saharan Africa. Malaria accounts annually for an estimated 610,000 lives lost. In 2024, 282 million malaria cases were reported worldwide, nine million more than in 2023, with 94% of cases and 95% of deaths occurring in Africa. Diarrhea is responsible for approximately 1.8 million childhood deaths in low- and middle-income countries (LMICs), of which approximately 375,000 occur in sub-Saharan Africa. ARIs contribute up to one-third of under-5 mortality – about 350,000 deaths in sub-Saharan Africa.
The transmission of these three preventable childhood killer diseases is closely associated with the home environment, where children spend most of their time, say researchers, who note that Star Homes provides ideas how to build better, healthier and more energy-efficient African homes as temperatures increase.
“Our Star Home design is intended to inspire those working in the building sector and with local communities to develop innovative designs for healthier homes. Major improvements in rural house design have the potential to make a substantial public health impact across hot, humid regions of Africa,” said Prof Seidlein.
“We must improve the climate comfort in African houses, relying on passive cooling rather than on air conditioning, which requires energy that is neither available nor affordable. After sunset, the upstairs space in the Star Home cools down rapidly, with optimized cross-ventilation ensuring a more comfortable climate during the night than in a traditional home and more comfortably allowing the use of bednets. With rising temperatures, such passive cooling is becoming increasingly essential. Not adapting to increasing temperatures is not an option,” said Prof Seidlein.