Influenza

Key Messages

  • Immunization against seasonal influenza has been shown to reduce the number of hospitalizations and deaths.
Local Epidemiology

To obtain the latest statistics on influenza and other circulating respiratory viruses:

Note: the incidence of laboratory confirmed cases of influenza and other respiratory viruses in the community is greatly under-reported because the majority of persons with influenza-like illness (ILI) do not require or seek medical care, and do not undergo (are not eligible for) laboratory testing.
Signs and Symptoms

Symptoms: include, but are not limited to:

  • New or worsening cough
  • Shortness of breath
  • Fever (may be absent in the elderly or immunocompromised)
  • Sore throat
  • Headache
  • Myalgia
  • Lethargy
  • Gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea) in some children

Duration of illness: In most people, illness resolves within five to seven days. Complications are most common in the very young and the elderly; the mortality rate from influenza is highest in the elderly.
Infection Prevention and Control (IPAC) Measures

Key IPAC measure to prevent transmission in clinical office settings:

  • Provide self-screening signage at the entrance to the clinic
  • Ask ill individuals presenting for care to wear a surgical mask.
  • Triage persons with febrile respiratory illnesses into a separate waiting room (or exam room) or keep at least 2 metres away from other patients.
  • Make 70% alcohol-based hand-rub (ABHR), masks and tissues available in the waiting room.
  • Clean and disinfect horizontal surfaces in patient care areas between patients.
  • Clean and disinfect high-touch surfaces frequently throughout the day.
  • Make personal protective equipment (PPE: gloves, face shields, masks) and ABHR available for staff at point of care.
  • Emphasize to staff the importance of hand hygiene including when leaving exam rooms.
  • Recommend that all clinical office staff receive their seasonal influenza immunization as soon as it is available (i.e., before the start of the influenza season)

Mode of transmission:

Influenza virus particles are easily spread by contact and droplets which are released from infected persons when they sneeze, cough, or talk.

Period of communicability:

People become infectious 24 hours prior to onset of symptoms; viral shedding in nasal secretions usually peaks during the first three days of illness and ceases within seven days but can be prolonged in young children, the elderly and those who are immunocompromised.

For more information about IPAC:

Guidelines for all healthcare settings: 
Diagnosis / Laboratory testing
  • Laboratory testing for influenza is not available to community-based healthcare providers in Ontario, except through the Canadian Sentinel Practitioner Surveillance Network. Benefits of joining this network include:
    • Receiving influenza testing results for your patients
    • Contributing to influenza surveillance in the community
    • Contributing to understanding how well the influenza vaccine works each year
an NP swab
Reporting to Public Health

Report all suspected and confirmed respiratory outbreaks in institutions (e.g., hospitals, LTCH, retirement homes, shelters) to Ottawa Public Health by calling 613-580-2424 extension 26325. After hours, on weekends, or holidays: call 3-1-1 and ask to speak to the public health on call.
Management of Patients

Recommendations for Antiviral Therapy of Seasonal Influenza (2025) are provided by Ontario Health.

For institutional outbreaks, including long-term care and retirement homes, please see the section on Management of Institutional Outbreaks.
Management of Institutional Outbreaks

Report all suspected and confirmed respiratory outbreaks in institutions (e.g., hospitals, LTCH, retirement homes, shelters) to Ottawa Public Health by calling 613-580-2424 ex 26325 or call 3-1-1 during evenings, weekends and holidays. Ottawa Public Health will assist you with outbreak management.

Access OPH resources on Long-Term Care Facilities and Retirement Homes Outbreaks.

Other resources for outbreak management:
Immunization
Please visit our Influenza vaccine information for health professionals page for more information.  
Patient Information

Patient information is available at: 
Physician Resources

Laboratory Testing:

Surveillance reports:

Infection Prevention and Control:

Prescribing antivirals for influenza:

Outbreak management:

Immunization:

Contact Us

If you want to notify Ottawa Public Health about a suspected or confirmed respiratory outbreak in an institution, please contact us at 613-580-2424, extension 26325 or call 3-1-1 during evenings, weekends and holidays and ask to speak to public health on call.

Contact Us