Detection of human herpesvirus 6 in pediatric CSF samples: causing disease or incidental distraction?

Interpretation of human herpesvirus type 6 (HHV6) detection in the cerebrospinal fluid (CSF) of children can be complex; the virus can cause acute infection, reactivation, or can be inherited chromosomally integrated (iciHHV6). Our objectives were to determine the prevalence of HHV6 including iciHHV6 in CSF and compare the clinical and laboratory characteristics with and without iciHHV6 in our patient population. Overall, the prevalence of HHV6 and iciHHV6 was 2.4% and 0.85%, respectively. Children with iciHHV6 were significantly younger and less likely to present with fever. Septic infants (≤60 days) accounted for 65.2% (15/23) of the iciHHV6 patients. Patients with iciHHV6 had higher viral loads in CSF and whole blood. Twenty-one (91.3%) patients with iciHHV6 and 12 (33.3%) without ici-HHV6 were determined to have an incidental detection of HHV6 not associated with presenting symptoms. Molecular detection of HHV6 in CSF is not always associated with HHV6 infection and may represent iciHHV6 particularly in infants evaluated for sepsis.