Objective  To observe the stability of varicella-zoster virus(VZV) Oka vaccine(V-Oka) strain during subculture, and align VZV sequences between V-Oka strain and wild-type strain from chickenpox patients. Methods   V-Oka strain was subcultured to the 50th passage on human diploid cell MRC-5. VZV DNAs were extracted from the 32nd, 34th, 38th, 42nd, 46th and 50th passages of V-Oka strains and wild-type strains. The major genes(ORF31,ORF62,ORF68 and repeat regions)of V-Oka strains and wild-type strains were amplified by PCR and sequenced. DNA sequences between V-Oka strains and wild-type strains were aligned. Results  In comparison with DNA sequences of V-Oka strain in GenBank, ORF31, ORF62 ,ORF68, repeat regions sequences of V-Oka strains from the 32nd passage to the 50th passage were stable and seemed to be more attenuated. Unique mutations as same as in V-Oka stains were not observed in wild-type strains. Conclusions  The molecular genetic characteristics of V-Oka strains are stable till the 50th passage. The results of sequence alignment show that pathogenic strains in chickenpox patients are wild-type strains, but not V-Oka strains.

Herpes zoster (HZ) is an infectious skin disease resulting from latent varicella-zoster virus (VZV) recurrent infection in humans, and its incidence and severity are associated with advancing age as well as immunocompromise. Persons infected with VZV present chickenpox in childhood and HZ in adulthood. Almost 3 million adults suffer from HZ disease every year in China, but there is no effective treatment. Zostavax of MSD and Shingrix of GlaxoSmithKline are the main types of HZ vaccine available worldwide. This study reviews the epidemiology of HZ disease and the progress of HZ vaccines at home and abroad, to provide a theoretical reference for the prevention of HZ disease and the development of vaccines.

Objective  To evaluate the vaccination rate of the varicella attenuated live vaccine (VarV) second dose (VarV 2) among eligible children in China. Methods  A search was performed for VarV 2 vaccination rate related studies published in CNKI, China Biology Medicine, VIP, PubMed and Web of Science electronic databases from January 2013 to May 2022. Meta-analysis of VarV 2 vaccination rate was performed using Stata 15.0 software. Results  A total of 3 352 literatures were retrieved, of which 19 were included in this Meta-analysis. The pooled results showed that the VarV 2 vaccination rate of eligible children in China is 55.3% (95% confidence interval: 48.4%-62.2%, I²=100%). The VarV 2 vaccination rate of local children was higher than that of non-local children, and the VarV 2 vaccination rates varied little among children of different sexes. Sensitivity analysis demonstrated that the VarV 2 vaccination rate ranged from 53.5% to 57.1%, and the results of publication bias were negative. Conclusion  The VarV 2 vaccination rate in China is at a low level at present. It is recommended to implement the VarV two-dose vaccination strategy in a timely manner. Provinces that have implemented the two-dose vaccination strategy should take targeted measures to improve the vaccination coverage.

Objective  To establish a cell infection-based real time quantitative reverse-transcription PCR (RT-qPCR) method for infectious virus titration of live attenuated varicella vaccine. Methods  Specific primers and probe were designed according to the gene sequence of live attenuated varicella vaccine strain V-Oka. Confluent MRC-5 cell monolayers were inoculated with serial dilutions of reference and test samples. After incubation for certain time, cells were harvested, from which RNA was extracted and applied to one-step RT-qPCR reaction. Titers of test samples were calculated by parallel line analysis, and compared with results by plaque method according to Chinese pharmacopeia 2020 edition volume Ⅲ. Results  The suitable harvest time of varicella-zoster virus infected cells was 36-48 h, and the detectable titers ranged from 2.8-5.0 lgPFU/ml. Titers detected by RT-qPCR and plaque method had no statistically significant difference (t=1.09 for lyophilized vaccine and t=0.59 for vaccine bulk, both P>0.05). Conclusion  The cell infection-based RT-qPCR method is preliminarily established, which can be applied to titrate infectious virus in live attenuated varicella vaccine.

Varicella-zoster virus (VZV) causes both varicella and herpes zoster (HZ). After initial infection, VZV will be latent in the spinal cord or cerebral ganglion. HZ is a herpetic disease caused by the activation of latent VZV due to the reduced immunity of the body, and leads to the damage of nerve tissue and skin tissue. At present, there is no specific drug for HZ treatment, and HZ vaccine can effectively reduce the incidence and recurrence rate of HZ, as well as related sequelae and complications of HZ. This paper reviews the progress on HZ vaccines marketed and in development, in order to provide reference for its research and development.