Help please

Is there anyway to keep a newborn from getting sick? My 5 year old is sick, my husband is sick now I’m coming down with something. We have a week old baby and I’m so nervous he will get sick. Is there anything I can do? also if he does come down with a virus or cold what are the symptoms? Will he have to be admitted to the hospital or do I keep an eye on it at home? Please answer I’m really scared