COVID-19

The information on this dashboard comes from several sources.

Data for current respiratory season:

All data for the current respiratory season is extracted on Wednesdays for data up to the end of the previous surveillance week.

• Percent Positivity: Capacity Planning and Analytics Division (CPAD), Respiratory Testing Report
• Outbreaks: Ontario’s Integrated Public Health Information System (iPHIS).
• Hospital bed occupancy: Ministry of Health, SAS Visual Analytics Tool, COVID Regional Hospital and Hospital Utilization reports.
• Emergency department visits: Acute Care Enhanced Surveillance (ACES) system.

Historical data:

• Percent Positivity (Sep 2021–Aug 2024): Ontario Agency for Health Protection and Promotion (Public Health Ontario). Ontario respiratory virus tool, extracted March 20, 2024.
• COVID-19 outbreaks (Sep 2021–Jun 2024): Public Health Case and Contact Management (CCM) system, extracted June 27, 2024.
• Other outbreaks (Sep 2021–Aug 2024): Integrated Public Health Information System (iPHIS), extracted July 16, 2025.

• The dashboard is updated every Thursday throughout the respiratory season. Data refreshes dynamically but is usually complete by 4 p.m., depending on server times.
• Data are grouped by respiratory seasons, which follow public health surveillance weeks:
  • Each season runs from September 1 to August 31 of the following year.
  • Surveillance weeks run Sunday to Saturday.
  • Typically, the week that includes September 1 marks the start of each season (week 35).
  • The current season (2025–26) runs from August 24, 2025, to August 29, 2026.
  • Dates align with the FluWatch Public Health Agency of Canada surveillance week schedule (external link).
• Numbers may differ from other reports because of different data sources, methods, or extraction/update times.
• Data are continuously updated as more information becomes available and are therefore subject to change with future dashboard updates.
  • iPHIS is regularly updated, so numbers reflect the most recent data at the time of extraction.
  • Counts may increase or decrease after data cleaning, updates or corrections.
• All data (except hospital bed occupancy) include Halton Region residents only.
  • Hospital bed occupancy reflects usage in the four hospitals within Halton Region, regardless of where patients live.

The Snapshot tab gives a quick overview of current respiratory virus activity among Halton residents.
It shows four indicators for COVID-19, influenza, and RSV (respiratory syncytial virus).

1. Overall activity (based on percent positivity)

2. Percent positivity (combined for influenza A and B)

3. Active outbreaks

4. Hospital bed occupancy

Each week’s data is compared to the previous week. Changes are shown as:

• ↑ Higher (orange arrow): Activity increased
• = Similar (grey equals sign): Little or no change
• ↓ Lower (blue arrow): Activity decreased

The criteria for each indicator are explained below.

 1. Overall Activity

• Higher (↑): Activity level increased to a higher category 
• Similar (=): No change in activity level
• Lower (↓): Activity level decreased to a lower category

 2. Percent Positivity

• Any move from 0% = Higher
• Any move to 0% = Lower

If percent positivity in the previous week was below 10%:

• Higher (↑): Increase of 0.5 percentage points or more
• Similar (=): Change of less than 0.5 percentage points
• Lower (↓): Decrease of 0.5 percentage points or more

If percent positivity in the previous week was 10% or more 

• Higher (↑): Increase of 5% or more

• Similar (=): Change of less than 5%
• Lower (↓): Decrease of 5% or more

 3. Active Outbreaks

• Any move from 0 = Higher
• Any move to 0 = Lower
• Higher (↑): an increase of 2 or more outbreaks
• Similar (=): Change of less than 2 outbreaks
• Lower (↓): a decrease of 2 or more outbreaks

 4. Hospital Bed Occupancy

• If the average count in the previous week was under 25 beds:
  • Higher (↑): Increase of 5 or more beds
  • Similar (=): Change of less than 5 beds
  • Lower (↓): Decrease of 5 or more beds
• If the average count in the previous week was 25 or more beds:
  • Higher (↑): Increase of 20% or more
  • Similar (=): Change of less than 20%
  • Lower (↓): Decrease of 20% or more

• Percent positivity is the percentage of tests that are positive in a given week. It’s calculated by dividing the number of positive tests in a 7-day surveillance week by the total number of tests performed during a 7-day surveillance week.
• Tests are assigned to a surveillance week based on the date the specimen was collected.
• Each test is counted separately, even if the same person was tested more than once in a week or over time.
• Trends over time should be interpreted carefully, since testing methods and eligibility have changed.
• When testing numbers are low, percent positivity can fluctuate more and may be less reliable.
• Lab data are assigned to a public health unit based on the patient’s postal code. If that information is missing, the submitter’s postal code is used instead. This may occasionally result in a test being assigned to the wrong health unit.

• Outbreaks are assigned to a surveillance week based on the date they were reported to Public Health.
• The criteria for declaring an outbreak can change over time. The dashboard shows outbreaks as they were entered in iPHIS or CCM, based on the criteria in place at the time.
• Only outbreaks in institutional settings are shown. These include hospitals, correctional facilities, long-term care homes, and retirement homes.
• The “Other” category includes outbreaks caused by entero/rhinovirus, parainfluenza, metapneumovirus, measles, or unspecified respiratory infections. These do not involve COVID-19, influenza, or RSV.
•  Some outbreaks involve more than one respiratory virus (called multi-organism outbreaks).
• The dashboard counts each outbreak once, unless it involves more than one of COVID-19, influenza, or RSV.  For example:
  1. COVID-19 and metapneumovirus → counted as one COVID-19 outbreak
  2. COVID-19, metapneumovirus, and influenza → counted as two outbreaks (COVID-19 and influenza)
  3. Metapneumovirus and parainfluenza → counted as one “Other” outbreak
• Active outbreaks (shown as a line) include any outbreaks that were still ongoing for at least one day during the surveillance week, no matter when they began.
• New outbreaks (shown as bars) are only counted once in the week they are reported, even if they continue afterward.
• Because it takes time to declare outbreaks over and update records in iPHIS, active outbreak counts may temporarily appear higher until all updates and documentation are complete.

• Bed occupancy data for influenza and RSV is only available starting from November 2022.
• The data shows the average daily number of patients occupying a bed in Halton hospitals who have COVID-19, influenza, or RSV during each surveillance week. Since the number of occupied beds can change daily, this is an average across the week.
• Beds in Halton hospitals may be occupied by patients from anywhere, not just Halton residents. Halton residents hospitalized outside Halton are not shown.
• Patients might be in the hospital because of complications from COVID-19, influenza, or RSV, or they might be hospitalized for other reasons but test positive for one of these infections.
• If a patient is infected with more than one of these viruses (COVID-19, influenza, RSV), their hospital bed is counted separately in each relevant category.

• Visits are counted in the surveillance week based on the date the person visited the emergency department.
• The data includes visits by Halton residents to any emergency department in Ontario.
• Visits are automatically grouped by the main symptoms reported (“chief complaint”). Because this is based on symptoms, some visits classified as respiratory or influenza-like illness might not actually be confirmed respiratory infections.
• The percentage of visits for respiratory or influenza-like illness is calculated by dividing the number of visits in these categories by the total number of emergency visits during the surveillance week.

• Differences between respiratory seasons happen for many reasons, such as:
  1. Which virus strains are circulating
  2. How well vaccines match those strains
  3. Which age groups are most affected
  4. How severe the illnesses are
  5. How many people get vaccinated
• Changes in who is eligible for testing affect the number and proportion of tests done for viruses like influenza, COVID-19, and RSV.
• Measures to control viruses (like COVID-19 restrictions) can also change virus activity. For example, COVID-19 restrictions also reduced flu and RSV activity.
• Because of these factors, comparing disease activity between seasons should be done with extreme caution. Differences in viral activity, testing rules, case definitions, and containment measures limit how comparable the data is over time and need to be considered when interpreting this data. 

Viral wastewater testing is no longer conducted in Halton. Data from wastewater testing at the remaining sites in Ontario (all located outside Halton) can be found in the Public Health Agency of Canada’s Wastewater monitoring dashboard (external link).