Transcribed Historic Data from the Last Recorded Smallpox Outbreaks in Somalia, 1976-1977

Smallpox, caused by the variola virus, was responsible for millions of deaths worldwide before its eradication was declared by the World Health Assembly in 1980. While modern disease outbreaks are modelled using contemporary data, the potential use of smallpox as a bioterrorist threat remains a concern, continuing to generate debate about the most effective modelling strategies to inform public health preparedness. Understanding how to control an eradicated disease like smallpox relies on the analysis of historical data. This study focuses on transcribed smallpox outbreak data from Somalia’s last recorded outbreaks (1976–1977), which were not only the final outbreaks in Somalia but also the last naturally occurring smallpox outbreaks in the world. The original handwritten records, obtained from the World Health Organization by a Public Health England (now UK Health Security Agency) study team, were digitized from PDF format into a Microsoft Excel worksheet through manual transcription. To ensure data accuracy and consistency, rigorous validation processes were applied. The resulting line-list dataset comprises 3,255 recorded cases of variola minor smallpox and includes key epidemiological variables: national case series number, age, sex, date of rash onset, date detected, village/locality, district, region, regional outbreak number, and national outbreak number. The primary goal of this project is to make these historical data globally accessible to epidemiologists and infectious disease modelers, enhancing our understanding of smallpox transmission dynamics in Somalia during the eradication period and informing strategies for potential future outbreaks in naïve populations. This data transcription forms part of a broader initiative, which also includes: 1. A descriptive epidemiological study characterizing smallpox cases and estimating incidence rates during the final outbreaks. 2. A modelling study estimating the basic reproduction number (R) for smallpox using two different disease dynamic models. By preserving and analyzing these historical data, this project provides valuable insights for infectious disease preparedness and response, bridging past experiences with future public health strategies.