Last updated: December 7, 2023

To help stop the spread of respiratory viruses, including COVID-19, anyone who feels sick should stay home and complete the self-assessment tool to learn more about what to do next. Continue to follow public health measures and stay up-to-date with your vaccinations.


Influenza virus, also known as the flu, is a virus that spreads very easily that can infect the nose, throat, and lungs. It is caused by influenza A and B viruses. Each year in Canada, about 5 to ten per cent of adults and 20 to 30 per cent of children are infected with influenza, usually in the late fall and winter months.

Influenza is spread by droplets made when people with the virus cough, sneeze or talk. These droplets can then land in the mouths, noses or eyes of people who are nearby (within two metres). It has also been found that some respiratory viruses, including influenza, can spread through very small droplets called aerosols which can hang in the air for longer periods of time. Less commonly, a person may also get influenza when they touch a surface or object that has the virus on it and then touch their own mouth, eyes, or nose.

It can take from one to four days to develop the influenza illness after being infected with the virus. People with influenza may infect others beginning from one day before symptoms start until about five days after becoming sick. Children and people with weak immune systems may spread the virus for a longer period of time.


It can be hard to tell the difference between flu symptoms and other respiratory viruses, such as COVID-19.

The most common symptoms include:

  • Fever
  • Cough
  • Muscle aches and pain

Other flu symptoms can include:

  • Headache
  • Chills
  • Loss of appetite
  • Feeling tired
  • Sore throat
  • Runny or stuffy nose
  • Nausea, vomiting and diarrhea may also occur, especially in children


It can be difficult to tell influenza from other viral or bacterial causes of respiratory illness as the symptoms are similar. If a healthcare provider needs to know if you are sick with influenza, they can test for it by swiping the inside of your nose with a swab to collect the virus and send to a lab.

Get tested and treated for COVID-19, if eligible.


Most healthy people who get influenza will not need medical treatment. Antiviral drugs are prescription drugs that may be used to lessen symptoms and prevent complications. Antiviral drugs are usually used early to treat hospitalized patients, people with severe influenza illness, and people who are at higher risk for complications based on their age or other health conditions. For more information, see What You Should Know About Flu Antiviral Drugs (Centers for Disease Control and Prevention), or speak with a healthcare provider.

Most people will recover within a week to ten days. Some people are at greater risk of complications which include pneumonia, ear infections, sinus infections, dehydration and worsening of chronic medical conditions, such as heart disease, asthma, and diabetes. Each year in Canada, about 12,200 people are hospitalized and 3,500 die due to influenza and its complications.

Those at high risk of influenza-related complications or hospitalization include:

  • People with chronic health conditions, including diabetes, heart, and lung disease
  • People who live in long-term care homes and other chronic-care facilities
  • Pregnant people
  • Indigenous people
  • Children under five years of age
  • People 65 years of age and older


If you have respiratory virus symptoms/influenza, the Ontario Ministry of Health recommends the following:

  • Stay home and get plenty of rest
  • Drink lots of fluids
  • Speak to a health care provider or pharmacist about over-the-counter medications that can help you feel better (such as basic pain or fever relievers) but do not give acetylsalicylic acid (ASA or Aspirin®) to anyone under the age of 18 years old
  • For muscle pain, use a hot water bottle or heating pad — apply heat for short periods of time
  • Take a warm bath
  • Gargle with a glass of warm salt water or suck on hard candy or lozenges, except for young children
  • Use spray or saline drops for a stuffy nose
  • Avoid caffeine, alcohol, and tobacco

Contacting a Health Care Provider

If you have questions about your illness or you don’t start to feel better after a few days or your symptoms get worse, call a health care provider, or 811 (TTY: 1-866-797-0007) to talk to a registered nurse 24 hours a day, 7 days a week. Calls to 811 do not need you to provide your OHIP number and all information is free, secure, and confidential.

Caring for Children with Respiratory Symptoms

The Ontario College of Family Physicians has created a fact sheet with tips for parents/guardians on caring for children with respiratory symptoms, including how to help support your sick child at home and when to call a health care provider for a respiratory illness.

Getting the flu vaccine each year is the best way to prevent influenza. Flu vaccine prevents illness, doctor’s visits, and hospitalizations. Each year, there is a new vaccine to protect against the influenza virus strains that are expected in the coming respiratory virus season. Even if the strains have not changed, getting vaccinated every year is needed for the best protection as immunity wears off within a year.

Follow these tips to help protect yourself, your loved ones and those most vulnerable in our communities: clean your hands frequently with soap and water or alcohol-based hand-sanitizer; avoid touching your eyes, nose and mouth with unclean hands; wear a well-fitting mask in crowded indoor settings, especially if you are at higher risk for severe illness; clean frequently touched surfaces such as doorknobs and mobile devices; cover your cough and sneeze with a tissue or your shirt, not your hands; stay away from people who are sick; and stay home when you are sick.

Flu vaccination is recommended for everyone aged six months and older. How much protection the vaccine gives depends on a person’s immune system and the match with the virus strains spreading that year.

Children six months of age and older and adults can get the flu vaccine at the same time, before or after a COVID-19 vaccine.

The vaccine provides some protection even when the match is not exact. Flu vaccines are about 50% effective in preventing the flu in healthy adults. The vaccine also reduces the risk of serious flu complications by 50 per cent.  The flu vaccine cannot make you sick from influenza because it does not contain any live virus. It takes two weeks for your body to develop an immune response from the vaccine.


Children under the age of nine years old who are getting the flu vaccine for the first time need a second dose at least four weeks after the first dose.

Adults 65+

The flu can make older adults very sick. There are two vaccines (Fluzone® QIV-HD, Fluad® TIV-adj) approved just for seniors to give better protection against the flu. Both vaccines may cause soreness, redness and swelling where the vaccine was given, lasting a few days longer than the standard flu vaccine.

The most important thing is for older adults to be vaccinated. Do not delay vaccination to wait for a particular vaccine product.

Pregnant People

The flu is more likely to cause illness that results in hospitalization in pregnant people than in people of reproductive age who are not pregnant. The flu may also be harmful for the developing baby . The flu vaccine is safe and recommended for pregnant and breastfeeding people to reduce the risk of getting very sick from the flu. Vaccination can also protect the fetus and newborn.

Side Effects & Risks

It is much safer to get the flu vaccine than to get the flu. Flu vaccines are safe, and side effects are usually mild and last only a few days.

Common side effects include:

  • Pain, redness and swelling in the area where the vaccine was injected
  • Headache
  • Fever
  • Muscle aches
  • Joint pain
  • Feeling tired

Side effects in children can include irritability, drowsiness or loss of appetite.

In rare cases, serious allergic reactions (anaphylaxis) can occur. Seek medical attention if you have trouble breathing, rash or swelling of the face and throat. Allergic reactions can be treated and are usually temporary. The risk of Oculo-Respiratory Syndrome  is very low. The risk of Guillain-Barré Syndrome  after flu vaccination is also very low, at about one case in a million flu vaccines given. The risk of Guillain-Barre Syndrome is higher following an influenza infection.

Talk to your Health Care Provider

Always tell your health care provider if you have allergies or if you have had side effects from a vaccine in the past. This vaccine is not for people who have had any allergic reaction to flu vaccine (anaphylaxis) in the past or people who have had Guillain-Barré Syndrome (nerve damage causing muscle weakness or paralysis) within six weeks after flu vaccination. People with a history of Oculo-Respiratory Syndrome (presence of at least one of the following symptoms: red eyes, cough, wheeze, chest tightness, difficulty breathing, sore throat, or facial swelling) can get the vaccine but should speak with a health care provider first.

Anyone six months of age and older are encouraged to get their COVID-19 and flu vaccines as soon as eligible. Only one appointment is needed to get both the COVID-19 and flu vaccines when booked through the Provincial Booking System.

COVID-19 and flu vaccines are also available at participating pharmacies, and some primary care providers with a valid OHIP card. At pharmacies, flu vaccines are available for ages two and older, and COVID-19 vaccines are available for six months of age and older.

TPH mobile clinics will continue to offer COVID-19 and flu vaccines to people living in shelters and naturally occurring retirement communities, and clients of newcomer agencies.

How to Get Your Flu Vaccine Safely During the Respiratory Season

  • Contact your local pharmacist or health care provider to make an appointment for you and your family members
  • Self-screen for COVID-19 before going to your appointment
  • Stay home if you feel sick, even if your symptoms are mild
  • Wear a mask

Find more information on where to get your vaccines.