Four strains or three? This is the first year that a flu shot has been made available that protects against four strains of influenza. The added strain is a B-type flu that mostly causes illness in young children, but the shot costs a bit more and probably won’t be everywhere. Get the “tried and true” three-strain if it’s all that’s available.
Needle-free options. The nasal-spray vaccine known as FluMist—used primarily for very young children—will protect against four strains this year. Adults who dislike big needles can ask for a Fluzone Intradermal, whose ultrathin needles only go skin deep.
High-dose and egg-free vaccines. Seniors are often given higher doses of the flu vaccines to “jump-start” their immune system. People who are allergic to eggs finally have their own option, in Flublok. Other vaccines are grown in chicken eggs; not this one.
Source: Time.com