I've never taken flu immunization. Mostly my immune system handles things. Th eone time I thought I had the flu it turned out to be pneumonia from cutting ceramic tile without a breather (a stupidity I regret, but not a flu). If I get a bout of flu, I figure it will lose and make my immune system stronger for it. That's been my experience so far. I do listen carefully to medical advice on other matters, though. But I have to feel comfortable in my own skin about it.