I am a little over four months post removal and am trying to get my cycle more regular and balance my hormones with help from my excellent naturopath who specializes in women's hormones. Mirena caused me to have low estrogen and no ovulation.
I haven't had the flu and I hope I don't because I've heard it's a doozy this year. I got a terrible cold last year in March and April and these were just before I noticed the mirena side effects starting in. So I think it depressed my immune function.
I am reading Suzanne Somers's book Ageless right now (even though I'm 35!) and it has a lot of information about all of our hormones and their effects on our health and immune system and the havoc that can be wreaked if they are thrown out of balance by hormonal birth control or other things. Basically we become much more succeptible to illness. I would recommend it to anyone here, though I never thought of Somers as an authority before. It also talks about bioidentical hormones.