Globally, influenza has been responsible for more outbreaks than any other infectious disease over the past 23 years, followed by Middle East respiratory syndrome (MERS) and Ebola, finds an analysis of disease reports by the World Health Organization (WHO)1. The study also reveals the subjective way in which disease outbreaks are often reported, suggesting that this can affect how resources are allocated.

Public-health authorities use several data sources to track infectious-disease outbreaks, but the WHO’s Disease Outbreak News (DON) is one of the most influential. Global-health researcher Rebecca Katz at Georgetown University in Washington DC and her colleagues collected all 2,789 DON reports issued between 1996 and 2019 in a searchable database. The database includes the metadata pulled from each report, such as the location of the outbreak, type of disease and timeframe over which it progressed.