The most effective way to guard yourself and others against getting the flu is to get a flu vaccination each flu season. There are two kinds of flu vaccines available in the USA:
The Flu Shot — this involves an inactivated vaccine (containing dead flu virus) which is administered with a syringe and needle. It is approved for use in humans 6 months or older. This includes otherwise healthy people and those with chronic medical conditions.
The Flu Nasal-Spray — sometimes called LAIV (live attenuated influenza vaccine), this vaccine is made using weakened flu viruses that do not cause the flu. This is approved for use in healthy people 2-49 years of age who are not pregnant or expecting to be.
Flu vaccinations begin in September or when the vaccine is available and it continues throughout the flu season. While major flu outbreaks can happen as early as October, most of the time activity peaks in January or thereafter.