The parental strain of the attenuated virus (vOka) used in the varicella vaccine is circulating in China: implications for vaccine surveillance.

摘要

Varicella-zoster vims (VZV) is the etiological agent of both varicella (chickenpox) and herpes zoster (shingles). Primary infection with VZV causes varicella, which usually occurs in childhood. Reactivation of VZV in previously infected individuals results in a herpes zoster that occurs most commonly in the elderly. In 1974, a live-attenuated VZV strain was established and subsequently licensed for Vaccination in Japan (1). Comparison of the complete DNA sequences of the Oka vaccine strain (vOka) and the parental Oka strain (pOka) revealed there were only 42 nucleotide substitutions along the whole 125-kbp viral genome, 15 of which were located in the major transactivator ORF62 region (2). The high sequence homology between vOka and pOka increases the difficulty of distinguishing vOka from clinical isolates with the pOka genotype. The pOka-like wild-type strain constitutes 20-30% of all VZV isolates in Japan (3). In contrast, it seems a rare genotype in other countries such as the U.S. and Australia (4,5). In this study we report a case of herpes zoster infected by the pOka-like wild-type strain in a Chinese woman.