title: Antibody induced by one-dose varicella vaccine soon became weak in children: evidence from a cross-sectional seroepidemiological survey in Beijing, PRC.
abstract: BACKGROUND
  Numerous post-licensure studies, mostly from field epidemiological evidences such as outbreak surveys, have demonstrated the effectivenesss and insufficiency of one-dose varicella vaccine in outbreak control. Serological evidence of immunization failure is, however, relatively less reported in contrast. A cross-sectional seroepidemiological survey of Beijing residents was performed in 2012 in the People's Republic of China, after the one-dose varicella vaccine had been widely used for several years.
  
  
  METHODS
  Multistage stratified random sampling method was designed to recruit 2 144 subjects. The ELISA method was used to test the present blood samples collected and the reserve samples collected in 2008 to assess the trends of anti-VZV seroprevalence in the past 5 years and to determine the risk factors for varicella infection.
  
  
  RESULTS
  The age- and sex- adjusted overall anti-VZV seropositivity of Beijing residents in 2012 was 84.5%. Two groups' adjusted overall anti-VZV seroprevalence in 2012 showed obvious growth compared with 2008 (<1 yr old: from 6.3% to 16.9%; 1-4 yr old: from 27.6% to 57.2%). Reported one-dose vaccination history was 71.6% (149/208), 80.9% (182/225) and 82.2% (180/219) in the 1-4 yr, 5-9 yr, 10-14 yr age groups, respectively. Of subjects who had received the one-dose vaccine, 36% (216/603) showed negative anti-VZV concentrations (<110 mIU/mL); additionally 15.9% (96/603) of such subjects' anti-VZV concentrations were in the lowest positive concentration group (110-299 mIU/mL). Seropositivity in permanent residents of 1-9 yr old with verified vaccination was merely 61.8%. Various age groups (1-3 yr, 4-6 yr, and 7-9 yr) all showed seropositivity that gradually decreased with increasing of the interval between vaccination and blood sampling.
  
  
  CONCLUSIONS
  Mass varicella vaccination significantly improved the immunity of younger Beijing residents. However, vaccine-induced anti-VZV antibody soon became weak in children with high coverage (approximately 80%) after vaccination for several years which is significantly higher than reported in pre-licensure studies. A government-funded 2-dose immunization program with mandatory vaccination schedule for Beijing residents may need consideration in the near future.
authors.affiliation: Beijing Center for Disease Control and Prevention (CDC), Capital Medical Unversity School of Public Health and Family Medicine, 16 Hepingli Zhongjie, Dongcheng Dist, Beijing, 100013, P. R. China. suoluodan2004@163.com.
authors.forename: Luodan
authors.initials: L
authors.lastname: Suo
authors.affiliation: Beijing Center for Disease Control and Prevention (CDC), Capital Medical Unversity School of Public Health and Family Medicine, 16 Hepingli Zhongjie, Dongcheng Dist, Beijing, 100013, P. R. China. Lulibj@sina.com.
authors.forename: Li
authors.initials: L
authors.lastname: Lu
authors.affiliation: Beijing Center for Disease Control and Prevention (CDC), Capital Medical Unversity School of Public Health and Family Medicine, 16 Hepingli Zhongjie, Dongcheng Dist, Beijing, 100013, P. R. China. Chenmengx@hotmail.com.
authors.forename: Meng
authors.initials: M
authors.lastname: Chen
authors.affiliation: Beijing Center for Disease Control and Prevention (CDC), Capital Medical Unversity School of Public Health and Family Medicine, 16 Hepingli Zhongjie, Dongcheng Dist, Beijing, 100013, P. R. China. pxh17@sina.com.
authors.forename: Xinghuo
authors.initials: X
authors.lastname: Pang
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D000068476:Beijing; D002644:Chickenpox / Q000453:epidemiology / Q000517:prevention & control*; D019433:Chickenpox Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D002681:China; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012307:Risk Factors; D057566:Self Report; D016036:Seroepidemiologic Studies; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D019433:Chickenpox Vaccine