The Ontario Ministry of Health and Long-Term Care have set case definition criteria for outbreaks:
Influenza in LTCH/RH and Other Congregate Living Settings
Suspect Influenza Outbreak:
- Two or more patient/resident cases of acute respiratory infections (ARI)with symptom onset within 48 hours and an epidemiological link (e.g., same unit/floor/service area) suggestive of transmission within the setting AND testing is not available or all negative.
Confirmed Influenza Outbreak:
Two or more patient/resident cases of test-confirmed acute respiratory infections (ARI)2 with symptom onset within 48 hours and an epidemiological link (e.g. same unit/floor/service area) suggestive of transmission within the setting.
OR
Three or more patient/resident cases of ARI with symptom onset within 48 hours and an epidemiological link suggestive of transmission within the setting AND testing is not available or all negative.
Client Case Definition:
- Two or more new symptoms for the individual.
Clinical Compatible Signs & Symptoms:
- Fever/abnormal temperature
- Dry cough
- Productive cough
- Headache
- Nasal congestion
- Congestion/sneezing
- Sore Throat/hoarseness
- Muscle aches
- Malaise/fatigue
For more information, refer to Ministry of Health and Long-Term Care documents:
- Appendix 1: Case Definitions and Disease-Specific Information Disease: Influenza August 2024 or as current
- Recommendations for Outbreak Prevention and Control in Institutions and Congregate Living Settings, October 2024 or as current
Forms
Fax in Lab Confirmed Influenza Cases Form within 24 hrs. of identification of influenza as the causative.
Thinking about using antivirals?
Antiviral medication is recommended for the management of institutional outbreaks of influenza A and/or influenza B. Antiviral medications may be used for both the prevention (i.e., chemoprophylaxis) and early treatment of influenza infection. Antivirals play a key role in outbreak management and control. The use of antiviral medication, in conjunction with other outbreak IPAC measures, can quickly bring influenza outbreaks in health care facilities under control.
For more information, refer to the following documents:
- Ministry of Health and Long-Term Care:
- Appendix 1: Case Definitions and Disease-Specific Information Disease: Influenza August 2024 or as current
- Recommendations for Outbreak Prevention and Control in Institutions and Congregate Living Settings, April 2024 or as current
- Public Heath Ontario:
- Antiviral Medications for Seasonal Influenza, September 2023 or as current
Who in the facility should receive antiviral treatment during a flu outbreak?
All clients that have flu like symptoms should be treated with antiviral medication. It is ideal to initiate treatment within the first 48 hours after first symptom onset for maximum effectiveness.
Refer to the “Use of Antivirals for Prevention and Treatment of Clients During Influenza Outbreaks in Long-Term Care Homes/Retirement Homes” for more information.
Who in the facility should receive antiviral prophylaxis during a flu outbreak?
Any clients who are asymptomatic, on the affected unit, should receive prophylaxis immediately, regardless of vaccination status. Antiviral prophylaxis has been shown to be approximately 70% to 90% effective in preventing influenza. Antiviral prophylaxis should not be used to replace the seasonal flu vaccine because it can promote resistance to antiviral medications or reduce antiviral medication availability for those who are severely ill.
Any clients who are asymptomatic, on non-affected units, may be prophylaxed; this decision will be assessed on a case-by-case basis with the facility’s Medical Director and the WECHU. Non-vaccinated staff are also required to start antiviral prophylaxis prior to working their next shift or exclude themselves from the home for the duration of the outbreak.
How long should antiviral medication be given to clients and staff during an influenza outbreak?
Antiviral medication should be continued for 14 days or for 7 days after the onset of symptoms in the last person infected, whichever is longer.