Human judgement forecasting tournaments: A feasibility study based on the COVID-19 pandemic with public health practitioners in England.

Objectives: To explore the viability of running human judgement forecasting tournaments with public health practitioners, and to gather initial data on forecasting accuracy and participant perceptions of forecasting. Study design: Quality improvement study comprising two COVID-19 forecasting tournaments using Brier Skill Score scoring and a follow-up participant questionnaire. Methods: Over two forecasting tournaments, public health registrars in the East Midlands, UK, assigned probabilities to future possible binary events relating to COVID-19. Participants also completed a questionnaire on their experiences of forecasting. Results: There were 17 participants in the first tournament and nine in the second tournament, with no new participants. In both tournaments, the majority of participants scored a Brier Skill Score above the benchmark of 0. The median Brier Skill Score improved slightly between the two tournaments. Participants reported luck and changing political climates as impacting their performance. Participants reported forecasting in their day job but had received no formal training to do so. Conclusions: Forecasting is an important public health skill, and human judgement forecasting tournaments can be run amongst public health practitioners with little time and resource requirements. Further research would help identify whether training, teamwork or other interventions can improve public health forecasting accuracy.

Outbreak of Shiga toxin-producing Escherichia coli O157 linked with consumption of a fast-food product containing imported cucumbers, United Kingdom, August 2020.

BACKGROUND: In August 2020, an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 occurred in the United Kingdom. Whole genome sequencing revealed that these cases formed a genetically distinct cluster. METHODS: Hypotheses generated from case interviews were tested in analytical studies, and results informed environmental sampling and food chain analysis. A case-case study used non-outbreak 'comparison' STEC cases; a case-control study used a market research panel to recruit controls. RESULTS: A total of 36 cases were identified; all cases reported symptom onset between August 3 and August 16, 2020. The majority of cases (83%) resided in the Midlands region of England and in Wales. A high proportion of cases reported eating out, with one fast-food restaurant chain mentioned by 64% (n = 23) of cases. Both the case-case study (adjusted odds ratio (aOR) 31.8, 95% confidence interval (CI) 1.6-624.9) and the case-control study (aOR 9.19, 95% CI 1.0-82.8) revealed statistically significant results, showing that the consumption of a specific fast-food product was independently associated with infection. CONCLUSIONS: Consumption of a specific fast-food product was a likely cause of this outbreak. The only ingredient specific to the product was cucumbers. The supply of cucumbers was immediately halted, and no further cases have been identified.