The best way to protect yourself from these viruses is by regularly washing your hands with soap and water. Also, make sure to avoid contact with sick people (especially infants), and if you are already ill, stay at home until you are symptom-free.
If you suspect you have been heardle exposed to a coronavirus, see a doctor so that he or she can give you proper treatment. You should also monitor your health closely after you recover to make sure that it doesn't return.