COVID-19 case data: Glossary

Definitions of terms used on the COVID-19 case data graphs and tables.

7-day average
Each point on the "7-day average" line/chart is the average of the previous 7 days. This approach smooths out the data which makes it easier to understand general trends.
Active
The number of people who have tested positive and have not yet been changed to “resolved” or "deaths".
Cases per 100,000
The number of cases for every 100,000 people in the region. It is calculated by dividing the number of cases by the population, and then multiplying by 100,000. For example, if a region has a rate of 24 per 100,000 population, there are 24 cases for every 100,000 people.
Cumulative
The total number of cases or tests since we started counting them. Each day's total is added to the total of all previous days.
Deaths
The number of people with a confirmed case of covid 19 who died.
Effective reproduction number (Re)
An estimate of the average number of people 1 person will infect when they have covid 19 .
  • When Re is less than 1, the number of new cases are expected to decrease over time because 1 person will infect fewer than 1 other person.
  • When Re equals 1, the number of new cases will not change because 1 person infects 1 other person.
  • When Re is more than 1, the number of new cases are expected to increase. For example, if Re = 2, 1 person will infect 2 people. Those 2 people will then each infect another 2 people, and so on.
  • When Re is equal to or greater than 1, effective control measures are needed to reduce the spread, otherwise, the average number of new cases will keep growing.
Re can be translated into projections about how quickly the number of daily cases will increase or decrease. For example:
  • When Re equals 1.2, the number of new cases can be projected to increase by 33% in the next 7 days
  • When Re equals 0.8, the number of new cases is projected to decrease by 29% in the next 7 days
Hospitalized
The total number of people in the hospital because of covid 19, which includes people in an Intensive Care Unit (ICU) and people not in an ICU.
In ICU
This number includes patients who are in an Intensive Care Unit (ICU) levels 2 and 3 flex, neonatal, pediatric and adult. It includes people who are on ventilators and people who are not.
In ICU with a ventilator
This is the number of people in the ICU who are on a ventilator, which helps them breathe, because they cannot breathe on their own.
Likely source of infection
Close contact
Individuals who likely caught covid 19 from an infected person that they were physically close to.
Community spread
A case is considered “community spread” when someone tests positive but we cannot trace the source because the person:
  • did not travel
  • did not knowingly have contact with another infected person
  • is not associated with an outbreak
Outbreak setting
Individuals who caught covid 19 in a specific shared space or setting such as a workplace, long-term care home or daycare.
Travel
Individuals who travelled outside of Ontario within 14 days before their symptoms began.
Other
Information on the source of infection is currently pending or unspecified.
Percent positive
The proportion of lab tests processed that had a positive result. It is calculated by dividing the number of tests with a positive result by the total number of tests processed in a day, and then multiplying by 100.
Resolved
Cases are classified as “resolved” if they are:
  • reported as “recovered” in Ontario’s Case and Contact Management system (CCM)
  • not hospitalized and are 14 days past the day symptoms began or (if no symptoms) they tested positive
  • currently hospitalized and have a status of “closed” in CCM (indicating Public Health Unit follow-up is complete) and are 14 days past the day symptoms began or (if no symptoms) they tested positive
Cases are not classified as “resolved” if they result in death.
There was a spike in resolved cases on March 30 because the reporting changed. Before March 30, “resolved” was called “recovered” and only included people who tested positive for covid 19 but had since had two negative tests in a row, at least 24 hours apart.
Total cases
The number of cases since January 15, 2020. This number includes cases that have been changed to “resolved” or “deaths”.
Total tested
We changed how we report "total tested" on April 15:
  • Current definition (from April 15 on): the total number of tests completed
  • Definition until April 14: the total number of people tested