I had the H1N1 vaccine a week ago one Nov. 20th. I received it IM single dose. I had absolutely no side effects at all. Not even any soreness at the site. I was surpised most of the reg. flu shots I have had and other vaccines have given me some side effects, local soreness, fatigue etc. My 16 month old also got it on wed the 25th. She had redness and soreness at the site a slight fever over night but otherwise was fine.