Well, it’s a debate but the smartest thing to do is to strengthen the immune system: D, Zinc, C, Manganese, NAC, L-glutathione and a multivitamin/mineral. Sun will also make D. Also, exercise and good sleep. And good nutrition. Plenty of fruit and veggies – but starch – a polysaccharide, protein, and fat are also important, despite health gurus. The only really bad food is too much sugar. When I go out I also suck on a zinc lozenge.