Influenza - Prevention

Vaccines are now available to help prevent influenza infections. The composition of these vaccines is changed every year. A vaccine is designed to protect people against three specific influenza viruses—the viruses thought to be most likely to infect people in a given year. Scientists may or may not make good guesses as to the "most likely" flu viruses. When they are successful, the vaccine can be 70 percent to 90 percent effective in people under the age of sixty-five.

The U.S. Centers for Disease Control and Prevention recommend that people get a flu vaccine injection each year before the flu season starts. In the United States, flu season usually runs from late December to early March. Adults usually need only one dose of the vaccine. Children under the age of nine who have not previously been vaccinated will need two doses one month apart.

Side effects from influenza vaccinations are rare. People who have never had influenza may experience about two days of discomfort. They may have a slight fever, feel tired, and experience achy muscles.

Certain people should not have influenza vaccinations. They include infants under the age of six months and people who are allergic to eggs. These people can be given the antiviral drugs described if necessary. However, certain groups of people are strongly advised to be vaccinated. These groups include:

• All people over the age of sixty-five
• Residents of nursing homes and other health-care facilities, regardless of age
• Adults and children who have chronic heart or lung problems, such as asthma (see asthma entry)
• Adults and children who have other kinds of chronic diseases, such as diabetes (see diabetes mellitus entry), severe anemia (see anemias entry), blood disorders, or kidney problems
• Children and teenagers who are on long-term aspirin therapy
• Women who are in the last two-thirds of their pregnancy and women who are nursing
• People with weakened immune systems, such as AIDS patients (see AIDS entry), people who have received organ transplants, and patients receiving various types of medical treatments, such as chemotherapy or radiation therapy
• Anyone who has regular contact with people in any of the above groups, such as teachers, health-care personnel, and family members
• Travelers to foreign countries

An individual need not be in one of the at-risk groups to receive a flu vaccination. Anyone who wants to avoid the discomfort of an influenza attack may receive the vaccine.