OBJECTIVETo evaluate the breakthrough varicella infection rate and varicella vaccine effectiveness (VE) among children who received 1-dose varicella vaccine.

METHODSA total of 57 180 subjects for the consecutive 4-year birth cohorts were selected from the local children born between 2007 and 2010 in Yinzhou District, Ninghai County and Yuyao City. And they were followed up for varicella from 2008 to 2013. The recipients of the vaccinations were identified through Ningbo Immunization Information System and data on breakthrough infections among the recipients were collected by using China Information System for Disease Control and Prevention. The breakthrough varicella rate and the VE were calculated and the trends of them were described from 2008 to 2013 among 4-year birth cohorts. The cumulative incidence of varicella was compared between vaccinated and unvaccinated children among the consecutive 4-year birth cohorts.

RESULTSThe rate of varicella vaccine coverage, vaccine cumulative incidence among the cohorts was 96.74% (55 317/57 180) and 0.56% (321/57 180). The breakthrough varicella infection for 4-year birth cohorts was 0.44% (244/55 317), and for each birth cohort was 0.95% (142/14 928), 0.44% (61/13 855), 0.22% (29/13 433) and 0.09% (12/13 101), respectively. It was on the rise from 2008 to 2013 and the 2007 birth cohort of it increased fastest from 0.04% (6/14 928) in 2007 to 0.32% (48/14 834) in 2013. The vaccine cumulative incidence of these who vaccinated 1-dose varicella (the breakthrough varicella infection) was lower than these who were unvaccinated (the incidence: 6.25% (37/592), 3.52% (15/426), 3.69% (17/461) and 2.08% (8/384)) by each birth cohort (χ²= 130.27, P < 0.001 for 2007 birth cohort; χ²= 74.11, P < 0.001 for 2008 birth cohort; χ²= 162.80, P < 0.001 for 2009 birth cohort; χ²= 100.01, P < 0.001 for 2010 birth cohort). The vaccine effectiveness for 4-year birth cohorts was 89.33% (95% CI: 86.7%-92.1%) and for each birth corhort was 84.78% (95% CI: 77.94%-89.50%), 86.82% (95% CI: 77.82%-92.95%), 93.99% (95% CI: 89.27%-96.81%) and 95.60% (95% CI: 89.18%-98.21%), respectively. The effectiveness of each birth cohort declinedgradually from 2008 to 2013 and the 2009 birth cohort of it decreased fastest from 98.86% in 2010 to 66.83% in 2013.

CONCLUSIONSThe 1-dose varicella vaccine effectiveness was good, but breakthrough varicella infection rate was on the rise with time and the VE declined gradually from 2008 to 2013.

Chickenpox ; Chickenpox Vaccine ; Child ; China ; Humans ; Incidence ; Vaccination ; Vaccine Potency

Herpes zoster is an uncommon disease in children, especially in healthy children. The clinical studies and observations of herpes zoster has been focused to children with hemato-oncologic diseases or immuno-compromised conditions. Recently the association of herpes zoster after varicella vaccine (Oka strain) immunization has been concerned and some cases of normal children after varicella vaccination have been reported. We experienced two cases of herpes zoster in healthy children after varicella vaccination.
Chickenpox Vaccine ; Chickenpox* ; Child* ; Herpes Zoster* ; Humans ; Immunization ; Vaccination*

Objective: To investigate the breakthrough rate and antibody level of children vaccinated two doses varicella vaccine in Tianjin city, and to compare them with those vaccinated one dose. Methods: A total of 1 112 children who were vaccinated two doses varicella vaccine were selected as the experimental group. According to the same street and township, children who had received only one dose within one year of age difference, and whose first injection time was less than one month from the first dose of varicella vaccine in the experimental group were selected as the control group. A three-year prospective observation was conducted on the incidence of varicella in the two groups. 108 pairs of children in the two groups were selected to collect antivaricella serum in the first to third year. The rate of breakthrough cases, antibody level and antibody positive rate were compared by χ² test, t-test and variance analysis between and within the two groups in three years. Results: The cumulative breakthrough rate of the experimental group was 0.54%(6/1 112), which was lower than that of the control group 3.96% (44/1 112, χ²=29.544, P<0.001). The GMC level of antibody in the experimental group decreased year by year (F=18.291, P<0.001), and the GMC level in the control group also decreased year by year (F=91.383, P<0.001). There was significant difference in GMC level between the two groups (P<0.001). The difference of antibody positive rate in the experimental group was statistically significant in three years (χ²=11.107, P<0.01), there was significant difference in the positive rate between the first year and third year (P<0.01), there was no significant difference in the positive rate of the control group in three years (χ²=3.351, P>0.05). The positive rate of the experimental group was higher than that of the control group (P<0.001). Conclusion: Two doses varicella vaccine can significantly improve the antibody level and positive rate, but it still shows a downward trend with the extension of time. It is necessary to consider strengthening immunization according to the actual situation.
Antibodies, Viral ; Chickenpox/prevention & control* ; Chickenpox Vaccine ; Child ; Herpesvirus 3, Human ; Humans ; Infant ; Prospective Studies ; Vaccination

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

OBJECTIVETo evaluate the effect of outbreaks control in school settings after a 2 dose varicella vaccine immunization strategy implemented in Beijing.

METHODSEpidemiological data of varicella outbreaks in school and kindergarten settings, which were reported by all 16 districts (county) during 2007-2013 according to the technical management norms of Beijing, was collected. The first dose and second dose varicella vaccine coverage rate of eligible children after the 2 dose varicella vaccine immunization strategy implementation were estimated through BJIIMS. Based on above we analyzed the changes of outbreak quantity, case quantity and the distribution characteristics between the pre-adjustment era (2007-2011 years) and late adjustment era (2013) of the 2 dose immunization strategy.

RESULTSIn pre-adjustment era (2007-2011 years), an average of 74 (95% CI: 60-89) outbreaks was reported and 964 (95% CI: 812-1 116) cases were involved per year. In late adjustment era (2013): Outbreaks (35) declined 52.7%, involved cases (371) declined 61.5%; Outbreaks epidemic duration shortened from 22 days of pre-adjustment era to 18 days; Outbreaks involved 10-24 cases declined 64.7% (from 34 to 12); Outbreaks involved ≥ 25 cases declined 71.4% (from 7 to 2); Outbreaks of different school type as well as different regions without exception declined dramatically. Cumulative one-dose vaccine coverage in children of 2-6 yr of age was 89.6% (812 859/907 579), and cumulative second-dose vaccine coverage in children of 4-7 yr of age was 44.3% (289 764/647 732).

CONCLUSIONImplementation of a 2 dose varicella vaccine immunization strategy effectively controlled outbreaks in school and kindergarten settings.

Chickenpox ; Chickenpox Vaccine ; Child ; Child, Preschool ; Disease Outbreaks ; Epidemics ; Humans ; Schools ; Students ; Vaccination

OBJECTIVES: The reported incidence rate of varicella infection in Jeju-do is higher compared with the national average. This study aimed to examine varicella vaccination history and evaluate clinical manifestation of varicella cases in Jeju-do. METHODS: Based on the guideline suggested by the Korea Centers for Disease Control and Prevention (KCDC), two epidemic investigations for varicella infection were conducted in the first half of 2017. The history of varicella vaccination was confirmed using the Integrated Control System for Diseases and Health operated by the KCDC. RESULTS: Out of a total of 60 elementary school children as the study subjects, all had been previously vaccinated against varicella. Twenty cases (33%) showed mild clinical manifestations and no complications. CONCLUSIONS: As the government of Jeju-do has supplied a single-labeled vaccine since 2011, there is a need to evaluate the type of vaccination failure such as primary or secondary.
Centers for Disease Control and Prevention (U.S.) ; Chickenpox Vaccine ; Chickenpox* ; Child* ; Humans ; Immunization ; Incidence ; Jeju-do ; Korea* ; Vaccination*

The number of reported varicella cases is continuously increasing in Korea; however, associated medical utilization is declining. The ratio between varicella insurance claims and reports of passive infectious disease surveillance has gradually increased to > 80% since the second half of 2017. The recent increase in reported varicella cases is influenced by improved reporting. We calculated the varicella incidence and cumulative incidence in each birth cohort according to age. The cumulative incidence rate among children aged < 6 years in the birth cohort born after the National Immunization Program introduced the varicella vaccine was about 60% lower than among children born before
Chickenpox Vaccine ; Chickenpox ; Child ; Cohort Studies ; Communicable Diseases ; Humans ; Immunization Programs ; Immunization ; Incidence ; Insurance ; Korea ; Parturition

OBJECTIVES: The reported incidence rate of varicella infection in Jeju-do is higher compared with the national average. This study aimed to examine varicella vaccination history and evaluate clinical manifestation of varicella cases in Jeju-do.METHODS: Based on the guideline suggested by the Korea Centers for Disease Control and Prevention (KCDC), two epidemic investigations for varicella infection were conducted in the first half of 2017. The history of varicella vaccination was confirmed using the Integrated Control System for Diseases and Health operated by the KCDC.RESULTS: Out of a total of 60 elementary school children as the study subjects, all had been previously vaccinated against varicella. Twenty cases (33%) showed mild clinical manifestations and no complications.CONCLUSIONS: As the government of Jeju-do has supplied a single-labeled vaccine since 2011, there is a need to evaluate the type of vaccination failure such as primary or secondary.
Centers for Disease Control and Prevention (U.S.) ; Chickenpox Vaccine ; Chickenpox ; Child ; Humans ; Immunization ; Incidence ; Jeju-do ; Korea ; Vaccination

OBJECTIVE: To evaluate the cost/benefit of different vaccination strategies related to chickenpox vaccine. METHODS: The direct economic cost and indirect economic cost caused by chickenpox were obtained through questionnaire survey. The epidemic characteristics of chickenpox in Zhejiang province were studied by literature review. Dynamic model was set up by Matlab software based on the parameters of chickenpox, to predict the incidence trends of chickenpox with different immunization strategies (no vaccination, 1-dose vaccination, 2-dose vaccination) in future 40 years (2017-2056). A cost-benefit analysis was conducted, and the sensitivities of the main parameters were analyzed. RESULTS: Through the questionnaire survey of 105 cases, the direct and indirect economic cost per case was 506.84 Yuan and 1045.39 Yuan respectively, with the total of 1552.23 Yuan. During the prediction period (40 years), there would be 7.0908 million cases in strategy 2, which was 59.71% less than strategy 1 (17.5989 million cases). Total vaccination costs in strategy 2 were 2.366 billion Yuan, with a total economic gain of 33.741 billion Yuan and benefit/cost ratio (BCR) of 14.26:1. If strategy 3 was adopted, 2.7249 million chickenpox cases would occur, with a decrease of 84.52% compared with strategy 1. Total vaccination costs in strategy 3 was 4.495 billion Yuan, with a total economic gain of 44.309 billion Yuan and BCR of 9.86:1. Analysis showed that the vaccine price was the most sensitive variable, followed by the incidence of chickenpox in the absence of vaccine. CONCLUSIONS In Zhejiang province, one-dose strategy and two-dose strategy were both cost effective. It is suggested that the chickenpox vaccination should be included in the immunization program in Zhejiang province.
Chickenpox ; prevention & control ; Chickenpox Vaccine ; Cost-Benefit Analysis ; Humans ; Immunization Programs ; economics ; methods ; Vaccination ; economics

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