This is from the Columbia University press release (2/27/15) about the Hornig / Lipkin study. If the immune system is stuck in high gear, it might be so responsive to new infections that they never get the chance to develop into the flu. Of course, the downside of that is that we constantly have the symptoms of ME instead. If this is the explanation though, then it's hard to figure why we would remain "immune" to flu/colds after three years. Perhaps even after the cytokines drop the system can remain hyper-reactive. I didn't get any kind of flu/cold for almost a decade after I got ME, but, by that time, I had experienced improvement in some symptoms. As other have said, I think getting the flu is actually a sign of improvement. I also don't really buy the argument that the isolation of being ill keeps us away from coming into contact with viruses. I was not totally housebound for most of the that time and I had plenty of contact with people and crowds. Even so, I didn't get a flu or a cold for almost a decade.