Health and Demographic Surveillance System

For decades, a health surveillance system in rural Gambia has tracked the births, deaths, and illnesses of entire communities, generating the long-term data that underpins world-leading trials on malaria vaccines, pneumonia jabs, and child nutrition. This matters because most clinical trials in low-resource settings lack the decades of background data needed to measure a vaccine’s real-world impact. Without a continuous record of who lives where, who gets sick, and who dies, researchers cannot tell whether a new intervention is working or whether they are simply seeing normal seasonal variation. The system also links health facility records with household data, creating a single, accurate source of information that researchers can trust. If the current upgrade succeeds—moving to electronic data collection and linking hospital records with the surveillance database—researchers across the unit will gain faster access to curated, consistent data. This will make it easier to run new trials, spot emerging disease trends, and attract external collaborators. The system itself is a piece of research infrastructure: it does not test a single hypothesis, but it quietly enables dozens of life-saving studies that would otherwise be impossible.