INFLUENZA VACCINE

The influenza vaccination is an annual vaccination using a vaccine specific for a given year to protect against the highly variable influenza virus. Each seasonal influenza vaccine contains antigens representing three (trivalent vaccine) or four (quadrivalent vaccine) influenza virus strains: one influenza type A subtype H1N1 virus strain, one influenza type A subtype H3N2 virus strain, and either one or two influenza type B virus strains.[2] Influenza vaccines may be administered as an injection, also known as a flu shot, or as a nasal spray.

The U.S. Centers for Disease Control and Prevention recommend that everyone over the ages of 6 months should receive the seasonal influenza vaccine. Vaccination campaigns usually focus on people who are at high risk of serious complications if they catch the flu, such as the elderly and people living with chronic illness or those with weakened immune systems, as well as health care workers.

Most flu vaccines provide significant protection against the virus.[5] Despite somewhat limited research, there is no evidence that they can cause serious harm, and no reason for serious side effects to be a concern.