155. Identification of Varicella-Zoster Virus Infections Caused by Oka Vaccine Strain and Genotype Analysis in Children
Session: Poster Abstract Session: Big Viruses in Little People (Pediatric Viral Diseases)
Thursday, October 27, 2016
Room: Poster Hall
Background: Although outbreak of varicella or herpes zoster was decreased after introduction of varicella vaccine, varicella-zoster virus (VZV) infections caused by vaccine-type strains were reported. However there were limited studies to differentiate wild-type strains and vaccine-type strains in children. Therefore we sought to distinguish vaccine-type strains from wild-type strains, and determine the genotype of VZV in Korean children.

Methods: VZV was isolated from vesicular lesions of the pediatric patients hospitalized for varicella or herpes zoster at Seoul National University Children’s Hospital, 2009-2015. To distinguish the vaccine-type strain from the wild-type strain, sequencing analysis of open reading frame (ORF) 62 was performed. The genotype was determined by sequencing analysis of ORF 22.

Results: Twenty-three patients with varicella and 28 patients with herpes zoster were included (median age 10.0 years, 16 days-19 years), and 44 patients (86.3%) had underlying diseases. Among 28 patients with herpes zoster, 12 patients had a past history of varicella and 1 patient had herpes zoster. According to the sequencing analysis of ORF 62, 2 vaccine-type strains were identified in children with herpes zoster without past history of varicella. One vaccine-type strain was identified from a child with retinoblastoma receiving chemotherapy after 22 months of varicella vaccination, and the other was from an immunocompetent child after 5 months of vaccination. Other VZV strains were wild-type strains. Genotypes by ORF 22 were determined genotype J in all patients except one. Genotype E was identified in an infant with varicella imported from Egypt.

Conclusion: This study demonstrated that the vaccine-type strains were found in both immunocompromised and immunocompetent children with herpes zoster. A single genotype J is prevalent in Korean children after introduction of varicella vaccine. Continuous monitoring of vaccine related VZV infection should be required in children, and surveillance of VZV genotype is warranted with a possible chance of spreading imported genotypes.

Byung Ok Kwak, MD, PhD, Konkuk University School of Medicine, Seoul, South Korea, Joon Kee Lee, MD, Seoul National University Children’s Hospital, Seoul, Korea, The Republic of, Chi Eun Oh, MD, Kosin University College of Medicine, Busan, Korea, The Republic of, Hee-Sup Kim, MD, Pediatrics, Dongkuk University Ilsan Hospital, Dongkuk University College of Medicine, Gyeonggi-do, Korea, The Republic of, Eun Hwa Choi, MD, PhD, Department of Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea and Hoan Jong Lee, MD, PhD, Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea

Disclosures:

B. O. Kwak, None

J. K. Lee, None

C. E. Oh, None

H. S. Kim, None

E. H. Choi, None

H. J. Lee, None

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