How contagious is mono?

Mononucleosis is caused by a communicable virus that isn't as contagious as the common cold, according to the American Academy of Family Physicians. Commonly known as the kissing disease, mono is transmitted through the saliva of an infected person, and the virus is also found in an infected person's mucus.

Individuals who have been infected can spread mono during the symptomatic phase of the disease as well as a few months after the symptoms cease, notes MedlinePlus. A person who has mononucleosis should avoid kissing other people as well as sharing food, utensils and beverages with others since the virus can be spread via those modes.