Activation of human herpesvirus‐6 in children with acute measles

Virological and serological studies were carried out prospectively to evaluate the possible activation of human herpesvirus-6 (HHV-6) in 50 infants and children with acute measles by isolation of HHV-6 from peripheral blood and by determining neutralizing antibodies to the virus. All but 5 patients (90%) were seropositive to HHV-6 in the acute stage of measles and 18 (40%) had a significant increase in HHV-6 antibody titers thereafter, whereas only 2 of 27 patients who were initially seropositive to Epstein-Barr virus (EBV) viral capsid antigen (VCA) had a significant rise in antibody titers to EBV VCA. Among 18 patients with a significant increase in HHV-6 titers, the virus was isolated from the peripheral blood mononuclear cells of three patients in the early convalescent stage of measles. These results indicate that activation of HHV-6 may occur frequently a few weeks after primary infection with the measles virus.