Human Herpesvirus 6 Infection

Epidemiology and Prevalence

Approximately 85-90% of adolescents and 90% of children under 1 year have past HHV-6 infection, as indicated by a positive HHV-6 antibody, with nearly 100% of children infected by age 3 and 85% of healthy adults showing evidence of past infection 1
The majority of the population, including 90% of children before their first year of life and practically 100% of children before the age of 3, are infected with HHV-6, according to the Centers for Disease Control and Prevention (CDC) guidelines 1
Approximately 85% of healthy adults or those infected with HIV intermittently shed HHV-6 in their saliva, as reported by the CDC 1

A fourfold or greater rise in antibody titer between acute and convalescent samples is a diagnostic criterion for active infection, according to the MMWR Recommendations and Reports and the CDC 1
Detection of HHV-6 DNA in cell-free plasma by PCR indicates active viral replication and is a diagnostic criterion for active infection, as reported by the CDC 1
Detection of IgM anti-HHV-6 in infants and young children is a diagnostic method, according to the CDC 1

In adolescents, primary infection is rare, reactivation can occur but is generally clinically insignificant in immunocompetent individuals, and active infection is more concerning in immunocompromised patients, as stated by the CDC 1
IgM detection in adults is unreliable as it can be present during reactivation, according to the MMWR Recommendations and Reports 1
HHV-6 can produce a spectrum of neurological diseases, including encephalitis and febrile seizures, as stated by the CDC 1

In immunocompromised patients, ganciclovir or foscarnet may be considered as treatment options, using regimens and doses similar to those used for CMV disease, as recommended by the CDC 1
No significant association has been identified between HHV-6 reactivation and disease in HIV-infected patients, as reported by the CDC 1