How can someone protect from infection related to meds-induced immune suppression?

Many things: Wash hands often, stay away from ill people, don't touch your face after being in public (until you've washed your hands), wear a mask if you must be in a hospital, day care or other facility where people may be ill. Don't eat in restaurants that do not have an "a" rating, avoid pot lucks and buffets, don't share food, drink or utensils with others. Clean cuts quickly, use new razors, etc.