Flu shot, that is. The 2012-13 Northern winter season’s flu shot offers protection against three strains of the flu : two strains of human flu H1N1 H3N2 and one of swine flu. (Sounds like pig farmers should still not get too close to their piggies!). Here’s a nice YouTube video http://www.youtube.com/watch?v=ug-M1nIhfIA that shows how flu viruses mutate, and explains where the H1N1 and H3N2 numbering comes from. P.S. Got to love those words hemagglutinin and neuraminidase from the video .. sure to leave your Scrabble opponents in a ‘dase’ if you build one of those bad boys!