Ontario Respiratory Virus Tool

The Ontario Respiratory Virus Tool provides comprehensive epidemiological information on respiratory virus activity in Ontario, including COVID-19, influenza, RSV, and other respiratory viruses. Explore respiratory virus data including case trends, outcomes (hospital bed occupancy, ICU bed occupancy, and deaths), laboratory testing, and outbreaks.   

Updates as of October 3, 2025:

• Weekly key highlights (October–March): Summarize respiratory virus activity, including antiviral resistance and genomics.
• Data source update: All lab testing data (2020–present) now sourced from OLIS for consistency; replaces previous sources.
• Data label alignment: COVID-19 data previously labeled as episodes will now be referred to as cases. Moving forward, both COVID-19 and influenza data will be presented as cases for simplicity and consistency. See the Technical Notes for details.
• Expanded indicators:
• ICU bed occupancy for influenza and RSV
• Hospital admissions for COVID-19, influenza and RSV.
• Combined bed occupancy view for COVID-19, influenza and RSV.

For a detailed description of the enhancements, please visit our news post: October 2025–26 Enhancements to the Ontario Respiratory Virus Tool.

Key findings for September 21 – 27, 2025 (surveillance week 39)

COVID-19

• Percent positivity was low (8.6%), but overall activity was lower than the previous week.
• Highest proportion in those <1 years (9.4%) and 65 years and older (10.3%).
• XFG.3 was the most dominant lineage identified by whole genome sequencing  (Sept 7–13)

Influenza

• Percent positivity was low (0.4%), and overall activity was similar to the previous week.
• Influenza A subtypes H1N1 and H3N2 are circulating at comparable levels. See Influenza Strain Details tab.
• No antiviral-resistant isolates identified in Ontario. See Influenza Strain Details tab.

RSV

• Percent positivity was low (0.2%), and overall activity was similar to the previous week.