Canada’s 2026 flu season is getting underway, with federal health officials introducing updated methods for tracking influenza activity and reminding people to arrange their annual vaccination before seasonal transmission increases.
The Public Health Agency of Canada’s FluWatch+ program began using a revised national approach in September 2026 to classify influenza, COVID-19 and respiratory syncytial virus activity.
The system uses laboratory test positivity and historical seasonal data to place activity into categories ranging from low to very high.
The change is designed to make weekly comparisons between provinces and territories more consistent.
Federal activity levels may still differ from figures published by provincial and territorial health authorities because local jurisdictions can use their own surveillance methods and thresholds.
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What the flu season data will show
The federal respiratory virus surveillance report tracks laboratory-confirmed influenza detections, test positivity, outbreaks in high-risk settings and influenza-associated hospitalizations.
It also includes information from FluWatchers, a national volunteer program in which participants report symptoms such as cough and fever.
Those reports can provide an early signal of respiratory illness in the community, although they do not confirm that a person has influenza.
Federal surveillance data are an estimate of activity rather than a complete count of all infections.
Many people with flu symptoms are never tested, and reporting delays can cause numbers to change in later updates.
One benchmark used by the federal report is a 5-per-cent influenza test-positivity threshold.
A seasonal influenza epidemic is declared when that threshold is exceeded and at least 15 influenza detections are reported during the week.
What is different about the 2026-2027 vaccine
The National Advisory Committee on Immunization continues to recommend annual influenza vaccination for everyone aged six months and older who does not have a contraindication.
The 2026-2027 vaccine program is based on strains selected for the Northern Hemisphere season, including updated influenza A(H3N2), A(H1N1)pdm09 and influenza B components.
Canada’s available products include standard-dose, cell-based and high-dose vaccines, depending on age, product authorization and regional supply.
NACI recommends that adults aged 65 and older be offered a high-dose or adjuvanted influenza vaccine when available.
If those products are not available, an age-appropriate influenza vaccine should still be used.
Vaccination is especially important for young children, pregnant people, older adults, people with chronic medical conditions and residents of long-term-care or other congregate settings.
Health-care workers, household contacts of people at higher risk and regular child-care providers are also among the groups prioritized by NACI.
Timing matters for families
People aged nine and older generally require one flu vaccine dose each season.
Children aged six months to under nine years who have never received an influenza vaccine need two doses in the same season, given at least four weeks apart.
Children in that age range who have received at least one influenza vaccine dose in a previous season generally need only one dose this year.
Federal flu vaccine information says the vaccine can be administered at the same appointment as other vaccines, including COVID-19 vaccines.
It generally takes about two weeks for the flu vaccine to provide its best protection.
Flu vaccination does not protect against COVID-19, RSV or avian influenza A(H5N1), so people should follow the separate recommendations that apply to those illnesses.
What Canadians should watch next
FluWatch+ will continue publishing weekly information through respiratory virus monitoring in Canada as testing, outbreaks and hospitalizations develop across the country.
The National Microbiology Laboratory will also characterize a sample of influenza viruses collected during the season to assess how closely circulating strains match the vaccine components.
Those strain-characterization results were not yet available in the federal report when the 2026-2027 surveillance period began.
Vaccine coverage estimates are expected later in the season, while effectiveness estimates are typically released in the spring after sufficient data have been collected.
For individuals, the practical steps remain straightforward: arrange a seasonal flu vaccine, stay home when sick, improve ventilation where possible, wash hands regularly and consider wearing a well-fitting mask in crowded indoor settings when respiratory illness is circulating.
Anyone who develops severe symptoms, has difficulty breathing, becomes unusually drowsy or is at high risk of complications should seek medical advice.
Provincial and territorial health authorities remain the best source for local clinic availability, eligibility details and treatment guidance.
Frequently Asked Questions
When does Canada’s 2026-2027 flu season begin?
Federal surveillance for the 2026-2027 season is underway in the fall of 2026, with weekly monitoring of influenza detections, test positivity, outbreaks and hospitalizations.
Who should get a flu vaccine in Canada?
NACI recommends annual influenza vaccination for everyone aged six months and older who does not have a contraindication, with particular priority for people at higher risk of complications.
How many flu vaccine doses do children need?
Children aged six months to under nine years receiving influenza vaccine for the first time generally need two doses at least four weeks apart. Previously vaccinated children in that age group generally need one dose.
Can the flu vaccine be given with a COVID-19 vaccine?
Yes. The Government of Canada says influenza vaccines may be given at the same time as other vaccines, including COVID-19 vaccines.
How long does it take for a flu vaccine to work?
The vaccine generally takes about two weeks to provide its best protection.
Fact-Checked: Key details were checked against current Public Health Agency of Canada, FluWatch+ and National Advisory Committee on Immunization information for the 2026-2027 season.
Disclaimer: Local vaccine availability, eligibility and treatment advice may differ by province or territory; consult your health-care provider or local public health authority.