Who knows? I have chronic Lyme disease, it flares up, it goes away, it flares up, the remissions are less as I age, but living with chronic disease one learns that there are good days and bad days. I don't think I have been actually "sick" in a long time, but, I am pretty much a hermit anyway, by nature, so if something is "going around", I learned a long time ago to avoid it, for years, if the flu is going around, I wouldn't say, go to a movie in the winter. Working in health care, I have always been all about hand washing and contagion. I dont take vaccines because the last thing I want to do is stimulate my immune system! When it is stimulated, it attacks me, not whatever bug is around.