Why get the flu vaccine?
In Canada, flu season usually runs from November to April. The flu virus usually changes from year to year, which is why there is a new vaccine each year to protect people. It is important to get a new flu shot every year. Influenza or the flu is a common infectious, respiratory disease that begins in your nose and throat. It is more serious than a simple cold. It is highly contagious and spreads rapidly from person to person. Influenza affects 10% to 25% of Canadians each year. Canada’s National Advisory Committee on Immunization encourages all Canadians over age 6 months to get a flu shot.
Although most people recover from the flu within a week to 10 days, for some people, the complications from the flu can be severe, or even deadly. These complications can include bronchitis, pneumonia, kidney failure or heart failure. One of the most common complications related to influenza is a bacterial infection of the upper and/or lower respiratory tract. Symptoms of a bacterial infection include lack of improvement in a person’s condition after 3-5 days, and blood or mucous coming up when the person coughs. Adults and children who suffer from cardiac or pulmonary disorders (e.g. asthma, cystic fibrosis) may see their chronic condition worsen.
Young children are particularly susceptible to complications from the flu. Some symptoms of complications in children include, difficulty breathing, sudden paleness, fever or low temperature, inability to drink or breastfeed, vomiting more than 2-3 times in 24 hours, a stiff neck, lethargy or confusion, and convulsions or seizures. Pregnant women who contract influenza may develop pneumonia and may require hospitalization. Elderly people (65 years and older) have the highest rate of hospitalization and death from the flu. Common complications of the flu for seniors include bacterial infection and pneumonia.
Another benefit of the flu shot is that it may lessen the chance of a heart attack or stroke. According to a study published October 2013 in the Journal of the American Medical Association, the chance of someone in their mid-60s suffering a major cardiac event such as a heart attack, stroke, heart failure or cardiac-related death are cut by 36 per cent if they have had a flu shot within the previous year. And if they have already suffered a heart attack, their chances of suffering another major cardiac event within a year are 55 per cent lower if they get the vaccine. Dr. Jacob Udell at Women’s College Hospital, led the study.
Seasonal flu vaccines are designed to protect against infection and illness caused by the flu viruses research indicates will be most common during the flu season. “Trivalent” flu vaccines are formulated to protect against three flu viruses, and “quadrivalent” flu vaccines protect against four flu viruses. Flu vaccines do NOT protect against infection and illness caused by other viruses that can also cause flu-like symptoms. There are many other viruses besides flu viruses that can result in flu-like illness* (also known as influenza-like illness or “ILI”) that spread during the flu season.
No. While the flu vaccine is the single best way to prevent the flu, protection can vary widely depending on who is being vaccinated (in addition to how well matched the flu vaccine is with circulating viruses). In general, the flu vaccine works best among healthy adults and older children. Some older people and people with certain chronic illnesses might develop less immunity than healthy children and adults after vaccination. However, even for these people, the flu vaccine still may provide some protection.
Older people with weaker immune systems often have a lower protective immune response after flu vaccination compared to younger, healthier people. This can result in lower vaccine effectiveness in these people.
In general, the flu vaccine works best among healthy adults and children older than 2 years of age. Reduced benefits of flu vaccine are often found in studies of young children (e.g., those younger than 2 years of age) and older adults (e.g., adults 65 years of age and older).