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Information about the Flu and the Flu Vaccine

What is influenza?

Influenza is an acute respiratory illness that is caused by a virus. People who get influenza may have a fever, chills, cough, runny nose, sore throat, headache, muscle aches, extreme weakness and fatigue. Children can also have earaches, nausea, vomiting and diarrhea.

Influenza spreads through respiratory droplets from infected persons, for example, through coughing or sneezing. It is also spread through direct contact with surfaces and objects contaminated by the influenza virus, such as toys, unwashed eating utensils and unclean hands.

How are individuals protected against influenza?

Influenza vaccine is the best defence against influenza. NACI, the National Advisory Committee on Immunization, a national expert group on immunization, strongly recommends annual influenza immunization.

What is in this year's vaccine?

The four strain influenza vaccine is available to everyone over the age of 6 months. This vaccine provides broader protection against influenza. It consists of two influenza A virus strains and two influenza B virus strains. The specific strains may change from year to year to offer better coverage.

Flumist is not available this flu season.

Is there a special vaccine for Seniors?

If you’re 65 years or older, you’ll have three choices this year:

• the four-strain, regular vaccine
• a four-strain, high-dose vaccine
• a three-strain, adjuvanted vaccine (works a little faster) (fluad)

The high-dose vaccine is more concentrated which typically means better protection for those 65 years of age and older. The adjuvanted vaccine is faster acting. All three vaccines are recommended for this age group.

Do I need to get the influenza vaccine every year?

Yes, the influenza vaccine is needed each year. The influenza virus changes often, so it is necessary to get immunized with the influenza vaccine every year for protection from the new virus strains that may be circulating that year.

Is the influenza vaccine safe?

The influenza vaccine is safe and well-tolerated. Influenza vaccines that protect against four influenza viruses are made in the same way as the influenza vaccines that have been around for years that protect against three influenza viruses. These vaccines have undergone the same testing as other vaccines approved for use in Canada.

How well does the vaccine protect against influenza?

Influenza immunization builds up antibodies against the influenza viruses in the vaccine, making it easier to fight influenza infection before it starts. The quadrivalent influenza vaccine offers broader protection than the trivalent influenza vaccine since it contains four strains of influenza virus, two influenza A strains and two influenza B strains. The trivalent and quadrivalent influenza vaccine provide the same degree of protection against the three strains they share in common.

Generally, influenza vaccines offer about 60% protection when the vaccine and circulating strains are well matched. The quadrivalent influenza vaccine will offer extra protection if the additional B strain in that vaccine is in circulation during influenza season.

It takes about two weeks following immunization to develop protection against influenza; protection can last up to one year. People who receive the vaccine can still get influenza but if they do, they may not get as sick. The vaccine will not protect against colds and other respiratory illnesses that may be mistaken for influenza, but are not caused by the influenza virus.

Does the influenza vaccine protect me from COVID-19?

No. The flu vaccine does not protect against coronaviruses. It is strongly recommended that all individuals born in 2009 or earlier receive the full COVID-19 vaccine series as soon as possible. According to the National Advisory Committee on Immunization (NACI), the COVID-19 vaccines may be given on the same day, or any time before or after, the flu vaccine.


The influenza vaccine is also available through your health care provider or your local pharmacy.