Causes

The common cold is an infection of the nose and throat (upper respiratory tract infection) that can be caused by one of more than 200 viruses. Rhinoviruses are the most common.

A cold virus enters your baby's body through his or her mouth, eyes or nose.

Once infected by a virus, your baby generally becomes immune to that virus. But because so many viruses cause colds, your baby may have several colds a year and many throughout his or her lifetime. Also, some viruses don't produce lasting immunity.

Your baby can be infected with a virus by:

• Air. When someone who is sick coughs, sneezes or talks, he or she might directly spread the virus to your baby.
• Direct contact. Someone with a cold who touches your baby's hand can spread the cold virus to your baby, who can become infected after touching his or her eyes, nose or mouth.
• Contaminated surfaces. Some viruses live on surfaces for two hours or longer. Your baby may catch a virus by touching a contaminated surface, such as a toy.