Application of the Modified Grunow-Finke Risk Assessment Tool to the Sverdlovsk Anthrax Outbreak of 1979.

Introduction: The modified Grunow-Finke tool (mGFT) is an improved scoring system for distinguishing unnatural outbreaks from natural ones. The 1979 Sverdlovsk anthrax outbreak was due to the inhalation of anthrax spores from a military laboratory, confirmed by Russian President Boris Yeltsin in 1992. At the time the Soviet Union insisted that the outbreak was caused by meat contaminated by diseased animals. At the time there was no available risk assessment tool capable of thoroughly examine the origin of the outbreak.

Methods: This study aimed to retrospectively apply the mGFT to test its ability to correctly identify the origin of the Sverdlovsk anthrax outbreak of 1979 as unnatural, using data available up to 1992, before the disclosure of a laboratory leak. Data spanning from 1979 to 1992 were collected through literature reviews. Evidence related to each mGFT criterion was scored on a scale of 0 to 3 and independently reviewed by 3 assessors. These scores were then multiplied with a weighting factor and summed to obtain a maximum score. A final score exceeding 30 was indicative of an unnatural origin.

Results: The mGFT results assigned a total of 47 points to the Sverdlovsk anthrax outbreak, suggesting an unnatural origin with a 78% likelihood.

Conclusions: These findings align with the confirmed unnatural origin of the outbreak, highlighting the value of tools such as the mGFT in identifying unnatural outbreaks. Such tools integrate both intelligence evidence and biological evidence in the identification of unnatural outbreaks. The use of such tools for identifying unnatural outbreaks is limited. Outbreak investigation can be improved if risk assessment tools become integral to routine public health practice and outbreak investigations.