Correct, I've been told by medical professionals that there are hundred(s) of strains but the flu shot only covers the handful of strains they expect to be prevalent for that flu season. I have been wondering how they come up with that prediction though...
the challenge with influenza vaccines is that the virus can shift character faster than a vaccine can be produced so its a crap shoot of sorts for a good match.
This is why we need to perfect much more expedient vaccine production technology other than the attenuated virus method
The morbidity and mortality weekly report from a month or so back said that in intentional lab infections the influenza vaccine was only 45% effective in preventing infection this year.
