Viral Respiratory Mapper - ACES ED Visits

The Viral Respiratory Mapper is a pair of tools that provide real-time situational awareness of emergency department visits and hospital admissions in Ontario for reasons that may be related to viral respiratory diseases, including COVID-19 and influenza. ACES, or Acute Care Enhanced Surveillance (ACES), is an Ontario-wide system that monitors hospital registration records in real time to identify potential disease outbreaks or other public health threats. It uses natural language processing to scan the words or phrases included in the “chief complaint” or "reason for admission" and to sort the records into "syndromes". Monitoring syndromes in real time can identify an outbreak much faster than is possible using laboratory results, but syndromes are not clinical diagnoses.

The two Viral Respiratory Mapper tools, viewed together, provide a comprehensive overview of respiratory disease presentation to acute hospitals in Ontario. The ED Visits tool (found below) is the earliest available hospital signal to identify potential respiratory viral spread in the population. It is not specific to disease, especially COVID-19, and may capture non-viral respiratory illnesses. As the earliest signal, it can be used to provide situational awareness of the potential patterns of spread for early interventions. The Admissions tool (available here) is a marker of severity of illness and typically lags behind visits. However, it is more respiratory disease specific, and has been developed to specifically identify potential COVID-19 admissions.

This tool displays real-time emergency department (ED) visits to Ontario hospitals for respiratory-related complaints (the RESP syndrome). It uses the percentage of outpatient visits to EDs for the RESP syndrome as a measure of activity levels. It compares the percentages to local cut-offs, developed for each respiratory season based on historical ACES data, that classify activity into one of 4 categories: seasonal, moderate, elevated and high. The system has been active for the past 7 seasons and has helped describe influenza and respiratory activity.

The tool pre-dates the COVID-19 pandemic, which has greatly affected traditional respiratory and influenza seasons and healthcare seeking behaviour. This was especially true in early 2020 and so the data in the tool does not represent the respiratory activity in hospitals; the Admissions Mapper provides better situational awareness for this period. The 2022/2023 influenza and respiratory season will still be full of unknowns given the ongoing COVID-19 pandemic and the tool will be subject to this constantly changing landscape for a third season. Users of the tools are asked to keep this mind when viewing the data and be careful in making inferences or assumptions based on it.

How to use the Viral Respiratory Mapper - ACES ED Visits: The main information in the ED Visits Mapper can be viewed by Public Health Unit (PHU) or Local Health Integration Network (LHIN). Switch between the two geography levels by clicking the “LHIN” and “PHU” buttons in the top left corner. On each page, the righthand side shows the overall respiratory level classification (seasonal, moderate, elevated or high) for Ontario and a map with the local classifications. Hovering over the region in the maps provides more information. The lefthand side shows a graph of the daily and 7-day moving average percentage of visits and their change from the previous period. The dashboard defaults to showing the most recent data (the last day for the graph and the last complete week for the map), but historical data can be viewed by clicking the season and week filter at the top left. There are also additional graphs (click “See More Data”) which show current and historical respiratory seasons for all of Ontario. More information about the tool and how to use it can be found within the dashboard by clicking the “Help and Notes” button.

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