A 5-year-old girl with varicella-zoster virus meningitis who had received the VZV vaccine 18 months previously is reported from the University of Chicago. She presented with a 5-day history of fever, headache, and a rash on the face and trunk, with diffuse papules, vesicles, and scabbed lesions. CSF showed 715 white cells with 97% lymphocytes, protein 133 mg/dL, glucose 46 mg/dL (serum glucose 86 mg/dL), and no bacteria on Gram-stain. CSF was positive for VZV by polymerase chain reaction. After a 10- day course of acyclovir, she made an uneventful recovery. A follow-up hearing test 6 weeks later revealed a right-sided sensorineural hearing loss, which had resolved when tested 2 years later. 
COMMENT. In an earlier report of VZV meningitis in a previously immunized child, there was evidence of seroconversion 4 weeks after immunization (Naruse et al. 1993), and the child had been exposed to a case of varicella 2 weeks before the illness. In the present case, there was no laboratory evidence of seroconversion and no known exposure to varicella. Although rarely reported, breakthrough cases of varicella with neurologic complications may occur in vaccinated children.