title: Primary human herpesvirus-6 infection is frequently overlooked as a cause of febrile fits in young children.
abstract: Sera from 248 children aged 30-179 weeks were tested retrospectively for human herpesvirus-6 (HHV-6) IgG antibody avidity. Twenty-five children presented with febrile fits, in one case with a rash, exanthem subitum resulting from primary HHV-6 infection was diagnosed at the time, but in the others HHV-6 was not considered in the differential diagnosis even though two patients had a rash. In fact, five of the 25 patients experienced primary infection as shown by low avidity HHV-6 antibody. Although nine other of these patients were seronegative in the acute phase of the illness, and unfortunately convalescent sera were not available to confirm primary HHV-6 infection, seronegativity was clearly a risk factor for febrile fits (P = 0.03, odds ratio 3.14 for all children; P = 0.002, odds ratio 7.20 for children aged 70-179 weeks), and primary HHV-6 infection was a very likely diagnosis. The remaining 11 children had high avidity antibody, so HHV-6 was excluded as a cause of their febrile fits. HHV-6 may frequently be a cause of febrile fits, often without the typical rash of exanthem subitum, and this diagnosis is often overlooked by clinicians.
authors.affiliation: Department of Pathology, University of Cambridge, Addenbrooke's Hospital, United Kingdom.
authors.forename: K N
authors.initials: KN
authors.lastname: Ward
authors.forename: J J
authors.initials: JJ
authors.lastname: Gray
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D000915:Antibody Affinity; D002675:Child, Preschool; D005077:Exanthema Subitum; D005260:Female; D005334:Fever / Q000209:etiology* / Q000382:microbiology; D006566:Herpesviridae Infections / Q000150:complications / Q000175:diagnosis*; D015654:Herpesvirus 6, Human; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007223:Infant; D008297:Male
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G