While children can be infected with EBV, the symptoms are not bad enough to be called mono. Those at highest risk for mono are adolescents and young adults aged 15 to 35. Adults can get mono but it is rare since most people have been exposed to EBV before the age of 35.

Once a person has been exposed to EBV, whether they had mono symptoms or not, they retain the virus in their body along with antibodies that help keep it in check. This makes it unlikely that they will get mono again, unless their immune system becomes compromised or they are taking medications that can suppress the immune system. In rare cases, people do have recurrent bouts of mono.