Influenza can lead to pneumonia, hospitalization, and even death in some people, particularly the elderly and those with chronic medical conditions, such as heart or lung problems. Influenza spreads easily from infected persons to the nose and throat of others through coughing and sneezing. It is also spread through direct contact with contaminated surfaces, or objects like unwashed hands, toys and eating utensils, which have been contaminated by the influenza virus. Because the flu virus changes from year to year, last year's immunity won't help you with the virus that causes problems this year. That's why you need a flu shot every year.
Influenza is much worse than a cold.
Even healthy young people can become quite ill. You might bring the influenza virus home to a baby, older relative, or someone with a medical condition who can get serious complications from influenza. PVaccine effectiveness varies from one person to another. Protection from the vaccine develops about two weeks after the shot, and may last up to one year. In elderly people, the vaccine can prevent pneumonia and hospitalization in about 6 out of 10 people.