Information has been received from the CDC concerning a 4.5 year old male who on 11/14/1997 was vaccinated with one dose of varicella. He was exposed to his 11 year old sister who had developed chicken pox at the age of 9, and developed herpes zoster on 11/10/2000. On 12/01/2000 the patient experienced varicella. He was mildly ill with a low grade fever and approximately 150 vesicular lesions located on the trunk, perianal area, face and scalp. The patient was in the school two days before his rash, and on the day the rash was noted was sent home. 23 other children at the same daycare experienced varicella. Fifteen of whom were vaccinated with varicella and eight of whom were not. No further information is available. Per F/U 6/18/02: The sister's herpes zoster was confirmed by Tzanck preparation of her lesions. The pt was bedridden for 1 day and appeared "moderately sick" to his parents. Approx. 2 weeks after rash onset in the index case there were 17 secondary cases (5 cases in unvaccinated children and 12 cases in vaccinated children), and 2 weeks after the secondary cases, a 3rd generation of infections occurred (n-5). The final case of the 4th generation of infection occurred 2 weeks after the prior generation. Additionally, 1 nine year old child developed herpes zoster during the outbreak, 7 years after primary varicella infection (WAES01072736). A susceptible parent of 2 breakthrough cases developed greater that 500 lesions (WAES01072737). F/U info from a published article indicated that "95 (100%) parent and 94 (99%) provider questionnaires were returned. The median age of the 76 (80%) children who attented continuously was 4.2 years (range: 6 months-8 years); 74% were male. Vaccination coverage was 75%. Of 23 cases of varicella, 15 (65%) occurred in vaccinated children and 8 (35%) occurred in unvaccinated children. The index case was a 4 year old vaccinee who developed BT on 12/1/00, PCR in another. Vaccine effectiveness was 40.5% (95% CI: -7.2, 67) overall and 41.7% in the building where the outbreak was centered." No further information is available.  Reported on 04/11/2003: " Follow-up information from a published article as titled above indicated that the index patient was a healthy, vaccinated, four year old male who had an onset of rash on 12/01/2000, approximately three years after vaccination on 11/14/1997.  The patient attended a day care center two days before the onset of rash and briefly on the morning on which the rash erupted, before he was taken home.  the child was moderately ill, with a generalized rash consisting of approximately 150 vesicular lesions and a temperature of 102.5F, remained bedridden for one day, and had no complications.  His only known exposure to varicella-zoster virus was contact with an 11 year old sister who did not attend the day care and who had herpes zoster (confirmed by Tzanck testing) on her left arm and back beginning on 11/10/2000 (21 days before the onset of rash in the index patient).  The index case gave rise to 15 secondary cases in which 45.8 percent were among vaccinated children.  Follow-up information from a published editorial as titled above indicated that the child, who had been vaccinated three years previously, had moderately severe varicella due to what was undoubtedly the wild-type virus and transmitted this virus to 15 other children, most of who had also been immunized.  No further information is available.  A copy of the published article is attached as further documentation of the patient's experience.