How to boost your immune system what vitamins to take

I will list all adaptations and herbs I have always taken. NAC probably my first choice to stop a cold before it starts. I get a virus maybe one time a year for 3 days Max. Echinea, ginseng and rhodiola for my entire life but not everyday. Body creates a tolerance to these and they do not perform the same functions, if you were to take them everyday. Maybe twice a week at onset of symptoms.