What is Human Herpesvirus 6 (HHV-6)?

Herpes Virus That Infects Most People by Age 3

... and then goes dormant and stays in the body for the rest of your life.

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Disclaimer: This information isn’t a substitute for professional medical advice, diagnosis, or treatment. You should never rely upon this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.

HHV-6 is a ubiquitous herpesvirus that infects most people by age 3 and then goes dormant and stays in the body for the rest of your life. It can be reactivated, especially in people who are immunocompromised. It is mainly spread through saliva and actually has two species of HHV-6:

  • HHV-6A is the species we know very little about
  • HHV-6B is the main culprit for infections and reactivation

HHV-6 In Children

HHV-6 infection in children is a major cause of acute febrile illness (sudden fever) and accounts for 20 percent of ER visits for febrile infants (1). HHV-6 is associated with roseola, a contagious infection characterized by high fever and rash in children aged 6 to 24 months (2). There isn’t a treatment for roseola, but it usually goes away on its own.

HHV-6 In Adults

It’s rare to be infected with HHV-6 as an adult. Reactivation of the virus is most common in the immunocompromised and has been linked to a variety of diseases, including autoimmune disease, encephalitis, chronic fatigue syndrome, epilepsy, heart disease, and organ transplant complications, notably in the immunocompromised (3)(4)


  1. https://academic.oup.com/cid/article/33/6/829/329754 Strausbaugh LJ, Caserta MT, Mock DJ. Human Herpesvirus 6. Clinical Infectious Diseases. 2001;33(6):829-833. doi:https://doi.org/10.1086/322691.
  2. Human Herpes Virus 6. HealthyChildren.org. https://www.healthychildren.org/English/health-issues/conditions/skin/Pages/Human-Herpes-Virus-6.aspx. Accessed April 2, 2019.

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