The varicella vaccination pattern among children under 5 years old in selected areas in china

Human Vaccines & Immunotherapeutics

Che

et al. 2018

Self Cite

Objective To delineate seroepidemiology of VZV in children aged 1-14 years in Hangzhou, to evaluate immunological response of VarV via 2 dose regimen immunization of VarV, for improving immunization strategy of VarV. Methods From 2014-2016, a multi-stage stratified random sampling method was employed to select participants included via physical examination for children in the Community Health Centre in Hangzhou. Results were compared among 11 various age groups: 1-,2-,3-,4-,5-,6-,7-,8-,9-,10-,11-14 years. Demographic data and vaccination history of all subjects derived from Zhejiang Information System for Immunization Program. Then, the second dose of the VarV was conducted on children aged 4-6 years who had immunization history of one dose of VarV. ELISA was used to detect VZV IgG in serum samples. Results 895 subjects with available information were included. The rate of VZV IgG seropositivity was 65.59% and the geometric mean concentration (GMC) for VZV IgG was 5.14 ± 1.89 mIU/ml. The GMC in urban subjects were higher than rural ones. Both the rate of VZV IgG seropositivity and the GMC in children aged 4-6 years groups were statistically lower than participants younger than 4 years and aged 7-14 years (1-,2-,3-,7-,8-,9-,10-,11-14 years). 627 subjects had immunization history of VarV. Both the rate of VZV IgG seropositivity and the GMC in subjects had immunization history of VarV was higher than who had no immunization history.90 subjects were included after the 2nd dose immunization of VarV. Both the rate of VZV IgG seropositivity and the GMC were significantly increased after the immunization of the 2nd dose of VarV. Conclusions The GMC for VZV IgG in children aged 4-6 years were lower than participants groups (1-,2-,3-,7-,8-,9-,10-,11-14 years).2 doses regimen immunization of VarV are effective for increasing both the rate of VZV IgG seropositivity and the GMC in these subjects.

Section: Discussionmentioning

confidence: 99%

Seroepidemiology of varicella in Hangzhou, China in the vaccine era

Human Vaccines & Immunotherapeutics

Che

et al. 2018

Self Cite

“…Varicella immunization of children was started from 1998 in China, with single dose of varicella vaccination administrated at 12 months old. 6 In China, vaccines are classified into two groups, CategoryⅠvaccines and CategoryⅡvaccines. CategoryⅠvaccines are vaccines which have been included in the national immunization, and it was mandatory and free to people.…”

Section: Introductionmentioning

confidence: 99%

One single-center cross-sectional investigation on varicella antibody level of all age groups in Chinese people

Meng

Cheng

Human Vaccines & Immunotherapeutics

et al. 2020

Varicella outbreaks were mainly reported in developed regions with high vaccine coverage, but not in undeveloped areas. It is still not clear that whether the published data of varicella epidemiology could reflect the reality in China or not. In 2019, 657 subjects from People's Hospital of Chongqing Youyang County were included. Anti-varicella-zoster virus (VZV) IgG antibodies were determined by ELISA. The anti-VZV IgG levels were categorized as positive when values were ≥100 mIU/mL. Our results showed that the rates of anti-VZV IgG seropositivity (χ 2 = 328.957, P < .0001) and geometric mean titers (P < .0001) were significantly influenced by age. The seropositivity declined dramatically from 84.5% in subjects ≤3 m of age, to 7.9% in subjects of >3 m-1 y (P < .0001). Then, the positivity rate increased slowly as age to 26.7% in >1-<3 y (P = .0006), and 34.5% in 3-<7 y (P = .4294). A steady rise (45.6%) in positivity was observed in subjects aged 7-<18 y. After then, the positivity began to increase robustly. A total of 87.8% of adults aged 18-<40 y had acquired VZV-specific immunity (P < .0001). The highest positivity rate was found in 40-<60 y (98.3%) and ≥60 y (98.2%) group. In conclusion, most subjects of >3 m-<7 y age were susceptible to VZV. The proportion of subjects with natural infection-induced immunity increased with age. Nearly all subjects over 40 ages had positive anti-VZV IgG antibodies, which proved that they were infected by this virus in the past. These results suggested that VarV should be included in the national immunization program in China.

“…Thirdly, Shanghai's population increased from 18 million in 2006 to 24 million in 2017, mainly due to migration (five million individuals) from poorer economic areas. Inequalities of immunization coverage due to socio-economic differences exist in China and other countries (Danis et al, 2010;Yue et al, 2017;Zhu et al, 2014). VarV is a privately funded vaccine, and students from migrant families of low socio-economic status are less likely to receive VarV before or after moving to Shanghai, which may increase the risk of varicella infection.…”

Section: Discussionmentioning

confidence: 99%

“…A single dose of VarV has been recommended on a voluntary basis for healthy children in China since 1998. Although VarV is not included in the National Immunization Program in China, single-dose VarV coverage among children born in 2008-2012 was 73.6% in six provinces, and coverage was positively associated with economic development (Yue et al, 2017). Previous studies have shown that single-dose VarV performed satisfactorily in China, with vaccine effectiveness (VE) between 50.3% and 83.9% (Fu et al, 2010;Pan et al, 2018;Wang et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Varicella outbreak trends in school settings during the voluntary single-dose vaccine era from 2006 to 2017 in Shanghai, China

Xian

International Journal of Infectious Diseases

et al. 2019

To investigate varicella outbreak trends among schoolchildren during the voluntary singledose varicella vaccine (VarV) era in Shanghai, China. Methods: Trends in school varicella outbreaks from 2006 to 2017 were assessed using joinpoint regression models. The impacts of changes in single-dose VarV coverage among schoolchildren and implementation of post-exposure prophylaxis (PEP) strategies on outbreak trends were further analyzed. Results: In total, 265 varicella outbreaks involving 3263 cases were reported in Shanghai from 2006 to 2017. The number of outbreaks showed an increasing trend from 2006 to 2017 (t = 2.62, p = 0.026), especially in kindergartens. The proportion of breakthrough varicella cases among all outbreak-related cases showed an increasing trend from 30.4% in 2008 to 85.7% in 2017 (t = 7.45, p < 0.001). Single-dose VarV coverage among schoolchildren was 88.1%, and showed a significant increase from the 1996 to the 2008 birth cohorts, followed by a non-significant decline from the 2008 to the 2014 birth cohorts. During school outbreaks in which PEP campaigns were conducted, the varicella attack rate was significantly lower than those in outbreaks without PEP campaigns (1.2% vs. 1.4%; Chi-square = 23.35, p < 0.001). Conclusions: Even with high coverage, single-dose VarV is insufficient to prevent school outbreaks. The administration of VarV as PEP is an appropriate intervention for varicella outbreak control prior to implementing a two-dose VarV schedule.