• Pediatric Infection and Vaccine
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• v.22 no.2
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• pp.55-62
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• 2015

Purpose: Varicella Zoster Immune Globulin (VZIG) is available in Korea for post-exposure prophylaxis of the Varicella-zoster virus (VZV) in high-risk patients. In July 2013, the United States Centers for Disease Control and Prevention (US CDC) recommended extending the time for administration of VariZIG$^{(R)}$ from within 96 hours up to 10 days after VZV exposure. This study was performed to analyze the effectiveness of VZIG prophylaxis between the two groups of patients who received VZIG within 96 hours and more than 96 hours of exposure to varicella. Methods: A retrospective chart review was performed in pediatric patients who received VZIG at Samsung Medical Center, Seoul, Korea from January 2001 to December 2012. Results: A total of 91 patients were identified. Fifty-seven patients were male (62.6%) and the median age was 5.91 years. Thirty-nine patients (42.9%) were exposed to VZV in the hospital. Underlying diseases were solid tumors (41.8%), hematologic malignancies (40.7%), and others (17.5%). Forty-five patients (49.5%) were hematopoietic cell transplant recipients. Seventy-four patients (81.3%) received VZIG within 96 hours after VZV exposure. There was no significant difference in the development of chickenpox between the two groups (2.7% vs. 5.9%, P=0.4664). In 22 seronegative patients, we also observed no significant difference between the groups in terms of the development of chickenpox (6.6% vs. 0%, P=0.667). Conclusions: This study showed that the effectiveness of VZIG for the prevention of chickenpox was comparable between patients who received VZIG within 96 hours and those who received VZIG more than 96 hours after exposure to VZV.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.180-187
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• 2016

Purpose: This study described the post-exposure prophylaxis (PEP) and secondary varicella infection in children inadvertently exposed to varicella zoster virus (VZV) in the hospital. Methods: We retrospectively analyzed data from patients with VZV infection who were initially not properly isolated, as well as children exposed to VZV at the Seoul National University Children's Hospital between January 2010 and December 2015. The PEP measures were determined by the presence of immunity to VZV and immunocompromising conditions. Patient clinical information was reviewed via medical records. Results: Among 147 children hospitalized between 2010 and 2015, 13 inadvertent exposures were notified due to VZV infection. Five index children had a history of VZV vaccination. Eighty-six children were exposed in multi-occupancy rooms and 62.8% (54/86) were immune to VZV. The PEP measures administered to 27 exposed patients included varicella zoster immunoglobulin and VZV vaccination. Four children developed secondary varicella, which was linked to a single index patient, including one child who did not receive PEP and three of the 27 children who received PEP. The rates of secondary varicella and prophylaxis failure were 4.7% (4/85) and 11.1% (3/27), respectively. The secondary varicella rates were 1.9% (1/54) and 9.7% (3/31) among immunocompetent and immunocompromised children, respectively. Conclusions: Delayed diagnosis of VZV infection can lead to unexpected exposure and place susceptible children and immunocompromised patients at risk for developing varicella. The appropriateness of the current PEP strategy based on VZV immunity may require re-evaluation.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.61-66
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• 2002

Purpose : To determine wether varicella can be prevented by administration of oral acyclovir(ACV) during the incubation period of the disease. Methods : Starting 9 days after exposure to the index case in their families, ACV(40 mg/kg/day in four divided doses) was given orally to 20 exposed children for 5 days. Their clinical features was compared with those of 20 control subjects. Antibody titers to VZV were measured in both group 1 week and 4 weeks after finishing the oral ACV administration. Results : The mean age of family members with varicella(51.4 months) were significantly high compared to that of ACV prophylaxis group(28.5 months) and control group(31 months) (P<0.05). Among the 12 children with ACV prophylaxis who completed follow up blood sampling, nine children were diagnosed as VZV infection on the serologic test(75%). Among them six children showed positive VZV IgM on the first blood sample and two children showed serocoversion to positive IgM on the second test after ACV prophylaxis. One child who was negative on both IgM and IgG, showed positive IgG on the second test. The incidence of fever and severity of skin rashes were significantly low in children received oral ACV than in the control group. No or reduced number of maculopapular eruption were observed in the oral ACV group compared to multiple vesicles of the control group. Conclusion : In the present study, we observed that oral ACV prophylaxis to the family contacts is effective in reducing severity of skin lesion. It is likely that oral ACV 9 days after contact prevents or reduces blood dissemination of VZV. Little is known about clinical effect and immunity to the virus in exposed children with no varicella symptom after treatment. We propose the checking up antibody to VZV some period after oral ACV, and considering vaccination to whom with no antibody. But further more studies are needed to practical application of oral ACV for the postexposure prophylaxis of varicella.