Public Health Agency of Canada: Flu (seasonal influenza):
- Symptoms and treatment
- Spread, prevention and risks
- Get your flu vaccine (flu shot)
- Travel health advice
Ministry of Health:
Public Health Ontario:
Caring for Kids:
Flu
The influenza virus or "flu" is a respiratory illness that spreads most frequently in the fall and winter. The flu spreads from person-to-person through coughing, sneezing or having face-to-face contact (e.g., talking). While anyone can get the flu, the very young, the elderly and people with certain medical conditions are at higher risk of complications. The best way to prevent getting sick with the flu is to get the seasonal flu vaccine every year.
There are three main types of the influenza virus: A, B, and C. Types A and B are usually the viruses detected during the flu season, which usually runs between November and March each year.
For more information, view local Influenza activity on our respiratory dashboard page.
More information about the flu/influenza
Seasonal influenza: report to the Health Unit within one business day by fax (705-482-0670) or phone at 705-474-1400 or toll free at 1-800-563-2808, ext. 5229 if seasonal influenza is suspected or confirmed as per Ontario Regulation 135/18 and amendments under the Health Protection and Promotion Act, R.S.O., c.H.7.
Novel influenza: report to Health Unit immediately by fax (705-482-0670) and phone at 705-474-1400 or toll free at 1-800-563-2808, ext. 5229 if novel influenza is suspected or confirmed as per Ontario Regulation 135/18 and amendments under the Health Protection and Promotion Act, R.S.O., c.H.7.
After hours, weekends, and holidays, call 705-474-1400 then press 0 to speak with the Answering Service. The on-call CDC Public Health Nurse will get back to you as soon as possible.
Should one go to childcare, school, or work if they have the flu?
Ill individuals should remain home until they do not have a fever, do not develop any new symptoms, and symptoms have been improving for at least 24 hours (48 hours for nausea, vomiting, and/or diarrhea).
Follow the direction of your healthcare provider, or occupational health at your workplace.
The flu vaccine (flu shot) is the best way to prevent the flu/influenza. See our Walk-in Clinics page for more information about flu shots, COVID-19 and RSV vaccines.
COVID-19
Efforts to slow the spread of COVID-19 still matter. Get the latest guidance to help keep yourself and loved ones healthy.
See What's Circulating
Our Respiratory Dashboard offers a local snapshot of outbreak activity related to the flu, COVID-19, and other respiratory viruses.
Get the Facts.
Have a judgement-free conversation and get accurate vaccine information from Doctors at VaxFacts.
Healthcare provider information
Influenza vaccination should be offered annually to anyone six months of age and older who does not have a contraindication to the vaccine.
Influenza vaccination is particularly recommended for:
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- people at high risk of severe disease, influenza-related complications, or hospitalization
- people capable of transmitting influenza to those at high risk, including health care workers
- people who provide essential community services
- people whose occupational or recreational activities increase their risk of exposure to avian influenza A(H5N1) viruses
- Adults and children nine years of age and older should receive one dose of influenza vaccine each year.
- Children six months to less than nine years of age who have never received influenza vaccine in a previous influenza season should be given two doses of influenza vaccine in the current season.
- Children six months to less than nine years of age who have been vaccinated with at least one dose of seasonal influenza vaccine in any previous season should receive one dose of influenza vaccine per season thereafter.
See additional information below:
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- Influenza vaccines: Canadian Immunization Guide
- Health Care Provider Fact Sheet: Influenza Immunization for Individuals ≥65 years of age
- Health Care Provider Fact Sheet: Influenza Immunization for Individuals 6 months to 64 years of age
- National Advisory Committee on Immunization: Statement on seasonal influenza vaccines for 2026-2027
- Ministry of Health: Universal Influenza Immunization Program (UIIP)
The decision to initiate antiviral therapy should include a clinical assessment of the patient’s signs and symptoms, along with consideration of their severity of illness, risk factor(s) for developing influenza-related complications, elapsed time from the onset of symptoms and epidemiologic factors (e.g., prevalence and strain of influenza virus circulating in the community).
Antiviral therapy should be started as soon as possible for individuals indicated for treatment, ideally within 48 hours of symptom onset for the greatest clinical benefit. Antiviral therapy beyond 48 hours of symptom onset may also be considered in selected circumstances as described in the Ontario Health Document: Recommendations for Antiviral Therapy of Seasonal Influenza
Additional Resources include:
- Association of Medical Microbiology and Infectious Disease Canada: Use of antiviral drugs for seasonal influenza: Foundation document for practitioners - Update 2019.
- Canadian Paediatric Society: The use of antiviral drugs for influenza: Guidance for practitioners.
Infection prevention and control
Routine practices along with droplet and contact precautions are recommended. See Public Health Ontario's Best Practices for Routine Practices and Additional Precautions for additional information.
Public Health Ontario Laboratory performs confirmatory testing for influenza, see Respiratory Viruses (including influenza) for additional information.
Public Health Ontario:
Public Health Agency of Canada:
Public Health Ontario:
Public Health Agency of Canada:
Contact our Communicable Disease Control (CDC) program at 705-474-1400 or toll free at 1-800-563-2808, ext. 5229, or by email to cdc@healthunit.ca for more information.
Last updated: Sep 2026, by CDC