Syndromic surveillance to detect disease outbreaks using time between emergency department presentations.

OBJECTIVE: Early warning of disease outbreaks is paramount for health jurisdictions. The objective of the present study was to develop syndromic surveillance monitoring plans from routinely collected ED data with application to detecting disease outbreaks. METHODS: The study involved secondary data analysis of ED presentations to major public hospitals in Queensland and South Australia spanning 2017-2020. Monitoring plans were developed for all major Queensland and South Australian public hospitals using an adaptation of Exponentially Weighted Moving Averages - a process control method used in detecting anomalies in industrial production processes. The methods rely on setting a threshold (control limit) relating to the time between an event of interest (e.g. flu outbreak) using ED presentations as a signal to monitor. An outbreak is flagged as this time gets significantly smaller, and each event offers a decision point on whether an outbreak has occurred. The models incorporate differing levels of temporal memory to cover outbreaks of different sizes. RESULTS: The novel approach to real-time outbreak detection indicates outbreaks for individual hospitals coinciding with the first wave of the COVID-19 outbreak in Queensland and South Australia as well as the large 2017 and 2019 influenza seasons. CONCLUSION: Outbreak detection models demonstrate the ability to quickly flag an outbreak based on clinician-assigned ED diagnoses. An implemented syndromic surveillance approach can pick up geographic outbreaks quickly so they can be contained. Such capability can help with surveillance related to the current COVID-19 pandemic and potential future pandemics.

Characteristics of patients with COVID-19 hospitalised in South Australia during the first wave of the pandemic.

OBJECTIVE: To describe the first wave of hospitalisations of patients testing positive for COVID-19 in South Australia. METHODS: Pathology test results for COVID-19 between January and June 2020 were matched against state-wide ED and inpatient data sets. RESULTS: The impact of the first wave of COVID-19 on South Australian hospitals was 440 unique patients with COVID-19; median ED, hospital and ICU lengths of stay of 4.7 h, 9.8 days and 4.1 days, respectively; and a crude mortality rate of 0.23 deaths per 100 000 population (four deaths). CONCLUSION: The study sheds light on the characteristics of patients with COVID-19 hospitalised in South Australia.