Flu shots--national and provincial/territorial trends.

As well as sub-zero temperatures and snowstorms, flu virurses arrive with the Canadian winter. Healthy people usually recover from the fever, cough, headache and other symptoms in less than a week. But some—especially seniors and those with lung or cardiac conditions—may have more severe cases of the flu and may even need to be hospitalized. Influenza immunization programs were first directed at high-risk groups.1 In 1993, a national consensus conference recommended that seniors, younger people with serious chronic illnesses, and health care workers receive annual flu shots.2 A target vaccination rate of 70% was set for seniors and for people of any age with chronic conditions that increase their susceptibility to influenza. Since then, guidelines have become progressively more inclusive. In 2002, the National Advisory Committee on Immunization recommended that, in addition to those in high-risk groups and people in close contact with them, any person who wished to be protected against influenza be offered the vaccine.3 In 2004, the Canadian Task Force on Preventive Health Care recommended influenza vaccination for healthy adults and children.4