In my opinion, the best you can do is to not stress over the bits you can not control (rumors, numbers, etc). Stress will weaken your immune system. You can also reduce the load on your immune system by eating healthy (remove sugar, carbs) and getting exercise when you can. Get plenty of real vitamin C from green leafy vegetables, zinc, I'm sure you know all of this. If you have loved ones that smoke, try to get them to at least temporarily use the patch or nicotine gum for a while.
Intuitively, it would seem that resting and not doing any physical activities would leave more energy for the body to use to fight off diseases.
I guess I can stop using condoms now, as long as I sleep well and exercise my heart for half an hour a day... /s