How Global Threats Posed by Disease Outbreaks Have Shifted Over Time

The distribution of outbreaks through time. (top) Number of reports per year, broken down to highlight the top four diseases, which are reported substantially more often than all others (see Table 1). (bottom) The proportion of total reports of a disease, across years, that occur in a given year, for the top 25 reported diseases in alphabetical order. Courtesy of Carlson et al., 2023, PLOS Global Public Health

The World Health Organization (WHO) notifies the global community about disease outbreaks through the Disease Outbreak News (DON). These online reports tell important stories about both outbreaks themselves and the high-level decision making that governs information sharing during public health emergencies. However, they have been used only minimally in global health scholarship to date.

Carlson, et al. (2023) collated all 2,789 of these reports from their first use through the start of the Covid-19 pandemic (January 1996 to December 2019), and develop an annotated database of the subjective and often inconsistent information they contain. They discovered that these reports are dominated by a mix of persistent worldwide threats (particularly influenza and cholera) and persistent epidemics (like Ebola virus disease in Africa or MERS-CoV in the Middle East), but also document important periods in history like the anthrax bioterrorist attacks at the turn of the century, the spread of chikungunya and Zika virus to the Americas, or even recent lapses in progress towards polio elimination.

The researchers present three simple vignettes that show how researchers can use these data to answer both qualitative and quantitative questions about global outbreak dynamics and public health response. However, they also found that the retrospective value of these reports is visibly limited by inconsistent reporting (e.g., of disease names, case totals, mortality, and actions taken to curtail spread). They conclude that sharing a transparent rubric for which outbreaks are considered reportable, and adopting more standardized formats for sharing epidemiological metadata, might help make the DON more useful to researchers and policymakers.

Reference: Carlson CJ, et al.The world health organization’s disease outbreak news: A retrospective database. PLOS. Jan. 25, 2023.