I mean no disrespect, but many get ill because they do not wash their hands enough and touch their face (not saying you do that, but hand hygene is amazingly important.)

I learned a 'trick' in Germany...slice an onion and put it in a place where most convene in your house. The first time I did this, myself, my (then) husband and child were extremely ill (and had been for awhile.) I placed the onion in our living room, and within a couple of days it was covered in black 'something.' Yet, we were all well on our way back to health in that short a time. I have no idea if that is a 'placebo effect,' but it works!