Available by injection or nasal spray, the influenza vaccine offers patients a 60 percent less chance they will require treatment for the flu. The United States government recommends the vaccine for people aged 6 months or older and encourages vaccination as early as possible. Immunization is available in a trivalent format, which protects against three strains of flu, or a quadrivalent vaccine, which protects against four.
Anyone age-eligible for the vaccine may receive a traditional shot. Those 18 through 64 years of age may receive the intradermal shot, which involves a smaller needle. Individuals over 18 may also request an egg-free vaccine or a shot that contains virus material grown within an animal cell culture, while persons over 65 may request a high-dose shot. Quadrivalent shots are available in traditional format only, but patients aged 2 through 49 may request a nasal spray vaccine. Children 2 to 8 years of age receive preferential treatment for the nasal spray format.