Flu Report: About the Flu Report

Questions

Answers

How often is the Flu Report updated and where does the data come from?
The Flu Report displays flu data provided by the Public Health Agency of Canada (PHAC). PHAC collects flu activity information from each of the provinces and territories. This information is reviewed and tabulated, a process taking about a week to complete. Every Friday, PHAC posts a summary of flu activity and statistical information pertaining to the previous week (Sunday to Saturday). The data displayed is therefore about a week old and is not a forecast of flu activity.

Information about symptoms, prevention, the international flu situation and flu travel tips also comes from PHAC. Unless otherwise indicated, all flu data comes from PHAC.

Any further questions about the data provided in the Flu Report or about H1N1 please visit FightFlu.ca or your doctor.
What do the Flu Activity Levels mean?
Below are the Influenza Activity Levels Definitions for the 2011-2012 Flu Season:

1 = No activity: no laboratory-confirmed influenza detections in the reporting week, however, sporadically occurring ILI may be reported

2 = Sporadic: sporadically occurring sporadically occurring ILI and lab confirmed influenza detection(s) with no outbreaks detected within the influenza surveillance region†

3 = Localized:
(1) evidence of increased ILI* and
(2) lab confirmed influenza detection(s) together with
(3) outbreaks in schools, hospitals, residential institutions and/or other types of facilities occurring in less than 50% of the influenza surveillance region†

4 = Widespread:
(1) evidence of increased ILI* and
(2) lab confirmed influenza detection(s) together with
(3) outbreaks in schools, hospitals, residential institutions and/or other types of facilities occurring in greater than or equal to 50% of the influenza surveillance region†

* More than just sporadic as determined by the provincial/territorial epidemiologist.

† Influenza surveillance regions within the province or territory as defined by the provincial/territorial epidemiologist.

Flu Terms

Influenza-like illness (ILI) - Acute onset of respiratory illness with fever and cough and with one or more of the following - sore throat, arthralgia, myalgia, or prostration which is likely due to influenza. In children under 5, gastrointestinal symptoms may also be present. In patients under 5 or 65 and older, fever may not be prominent.

Outbreaks:
- Schools: Greater than 10% absenteeism (or absenteeism that is higher (e.g. >5-10%) than expected level as determined by school or public health authority) which is likely due to ILI.
- Hospitals and residential institutions: two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case.
- Other: two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case; i.e. workplace, closed communities.
What does the week number mean (i.e.: Week 35)?
The numbering of the weeks begins in January with Week 1 and Week 52 comes at the end of December.

For statistical purposes, the Flu Season officially begins in September and ends at the end of August. The first week of the 2011/2012 Flu Season was week 35.