The document discusses influenza (flu) and seasonal flu vaccines. It notes that flu season occurs between October and March and can cause serious illness and death, especially among those aged 65 and older. It describes that the seasonal flu vaccine protects against three or four flu virus strains, depending on the vaccine type. It recommends the vaccine for those aged six months and older, especially those at high risk. Side effects are mild and it may lessen illness symptoms if one gets the flu.