The reported incidence of varicella in Beijing from 2019 to 2021 were 63.8/100 000, 32.2/100 000 and 38.6/100 000, respectively. There were two VZV epidemics in Beijing each year, one peaked in May and the other in November. However, the first VZV epidemic almost disappeared in 2020. Among the cases involved in the varicella outbreaks in school, the proportion of the students with no history of vaccine immunization, 1 dose of immunization and 2 doses of immunization were 33.12%, 44.79% and 22.08%, respectively. The major body of VZV breakthrough cases was children aged 6-14 years (523/755, 69.27%). The proportion of moderate- or severe-rash were 55.32%, 39.06%, 29.96% in the three groups of cases with no immunization history, 1 dose of immunization and 2 doses of immunization, respectively (P<0.001). A total of 1 089 varicella samples were collected, and 837 (76.86%) were confirmed to be PCR-positive for VZV and were identified as VZV wild strains. 311 VZV strains were sequenced successfully, and 307 strains were clade 2 (98.72%), 1 clade 3 (0.32%) and 3 Clade 5 (0.96%). Compared with the representative strains, the nucleotide similarities of ORF22 fragments were between 99.4% and 100%, and amino acid similarities were between 99.4% and 100%.
Beijing/epidemiology* ; Chickenpox/epidemiology* ; Chickenpox Vaccine ; Child ; Herpesvirus 3, Human/genetics* ; Humans ; Schools ; Vaccination

With the determination of the whole genome sequence of varicella-zoster virus (VZV) virus, the successful breakthrough of infectious cloning technology of VZV, and the emergence of effective preventive vaccines, which have been proven to be effective and safe, varicella has become a disease preventable by specific immunity. This article will review the genomic structure, epidemiological characteristics, and research application progress of varicella vaccine and herpes zoster vaccine of varicella zoster virus to provide reference for primary prevention of the disease.
Humans ; Herpesvirus 3, Human/genetics* ; Herpes Zoster/prevention & control* ; Herpes Zoster Vaccine ; Chickenpox Vaccine ; Genomics

Objective: To investigate the genetic characteristics of varicella zoster virus (VZV) in Shandong province from 2020 to 2021. Methods: From April 2020 to December 2021, 85 herpes fluid samples from suspected varicella patients in Shandong province were collected. The qPCR was used to detect viral DNA and screen suspected samples. Six single nucleotide polymorphisms (SNPs) of ORF22 fragment and ORF38 fragment in positive samples were examined via PCR and Sanger sequencing to identify the viral genotypes. Four SNPs of ORF38 and ORF62 were examined to identify the vaccine and wild-type strains. The sequences were analyzed with Sequencher and MEGA7 software, using the VZV reference strain sequences from GenBank. Results: In the 85 samples suspected of varicella, 80 were VZV positive and wild-type strains belonging to Clade 2. Compared with clade 2 representative strains, the nucleotide and amino acid similarities of ORF22 fragment were 99.5%-100% and 98.5%-100%, respectively. SD20-1, SD20-5, SD20-6, SD20-8, SD20-9, SD20-10, SD20-11, SD20-12, SD20-13, SD20-30 and SD20-31 had a A➝G nucleotide mutation at 37990, causing amino acid change from glutamine to arginine. SD21-1 had a C➝A nucleotide mutation at 38059, causing threonine to asparagine during coding. Conclusions: From 2020 to 2021, all VZV strains in Shandong province are the wild-type strains belonging to Clade 2.
Amino Acids/genetics* ; Chickenpox ; Chickenpox Vaccine/genetics* ; Herpes Zoster ; Herpesvirus 3, Human/genetics* ; Humans ; Nucleotides ; Polymorphism, Single Nucleotide ; Real-Time Polymerase Chain Reaction