The Epstein-Barr Virus (EBV), also known as human herpesvirus 4, is a common human virus. It infects a vast majority of people globally at some point during their lives. Many individuals carry this virus without realizing it, as initial infections can be mild or even asymptomatic.
Global Prevalence of EBV
Epstein-Barr Virus is widespread, with over 90% of adults globally carrying the virus. Approximately 90-95% of individuals acquire the infection by 25 years of age.
The age at which primary infection occurs often differs between developed and developing countries. In many developing nations, exposure to EBV happens early in childhood, frequently resulting in mild or unnoticed symptoms. Conversely, in more developed countries, initial infections are delayed until adolescence or young adulthood.
In the United States, approximately 66.5% of children and adolescents between 6 and 19 years old show evidence of past EBV infection. About 54% of children aged 6-8 years have been infected, a number that rises to 82.9% for adolescents aged 18-19 years. Infection rates can also vary based on socioeconomic factors, with children from lower-income households showing higher seroprevalence.
How EBV Spreads
Epstein-Barr Virus primarily spreads through bodily fluids, with saliva being the most common transmission route. This is why EBV infection is often referred to as “the kissing disease.”
Beyond kissing, EBV can spread by sharing drinks, eating utensils, or personal items that have come into contact with an infected person’s saliva. Coughing or sneezing can also facilitate transmission. Less common but possible routes include contact with toys that children have put in their mouths, sexual contact involving blood or semen, blood transfusions, and organ transplants.
The virus is not considered highly contagious, requiring multiple exposures for acquisition. After an initial infection, the virus can persist in oropharyngeal secretions for several months, even up to a year.
Living with Latent EBV
Once a person is infected with Epstein-Barr Virus, the virus establishes a lifelong presence within the body. Following the initial infection, EBV typically enters a latent, or inactive, state. It primarily resides within specific immune cells known as B lymphocytes, particularly memory B cells.
During this latent phase, the virus remains largely dormant, and most individuals experience no symptoms. However, EBV can intermittently reactivate, leading to the silent shedding of viral particles, especially in the oropharynx. In healthy adults, the virus can be detected in their oropharyngeal secretions about 10-20% of the time, even without any noticeable illness.