title: Antitoxins for diphtheria and tetanus decline more slowly after vaccination with DTwP than with DTaP: a study in a Chinese population.
abstract: OBJECTIVE
  DTP vaccines are used for the prevention of pertussis, diphtheria and tetanus. In 2007, in Gaobeidian city, China, the DTwP vaccine was replaced with DTaP. This study described the diphtheria and tetanus sero-epidemiology in subjects vaccinated solely with DTwP or DTaP.
  
  
  METHODS
  Blood samples were obtained between October 2012 and June 2013 from 587 healthy subjects aged 2-17 years. Serum IgG antibodies against diphtheria and tetanus were determined using ELISA. Interrupted time series analyses examined the changes in antitoxin levels over time and analyzed the alterations in diphtheria and tetanus antitoxin levels after the vaccine switch.
  
  
  RESULTS
  Mean concentrations of diphtheria antitoxin and tetanus antitoxin were 0.074 IU/ml (95% CI 0.065-0.084) and 0.063 IU/ml (95% CI 0.053-0.076). The protection rates (antitoxins >0.01 IU/ml) for diphtheria and tetanus were 88.25% and 82.11%. Mean antitoxin levels for both diphtheria and tetanus decreased with increasing age, but this decrease was much slower for DTwP than DTaP.
  
  
  CONCLUSIONS
  Although the observed protection rates for diphtheria and tetanus were sufficient to prevent an outbreak at present, the means levels of diphtheria and tetanus antitoxins decreased with increasing age; therefore, booster vaccinations at 7 and 12 years of age would be strengthened in Gaobeidian city, China.
authors.affiliation: National Institute for Communicable Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, P.O. Box 5, Changping, Beijing 102206, PR China.
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: National Institute for Communicable Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, P.O. Box 5, Changping, Beijing 102206, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: National Institute for Communicable Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, P.O. Box 5, Changping, Beijing 102206, PR China.
authors.forename: Bingqing
authors.initials: B
authors.lastname: Zhu
authors.affiliation: National Institute for Communicable Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, P.O. Box 5, Changping, Beijing 102206, PR China.
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Gaobeidian Center for Disease Control and Prevention, Gaobeidian, Hebei Province 074000, PR China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Shi
authors.affiliation: Gaobeidian Center for Disease Control and Prevention, Gaobeidian, Hebei Province 074000, PR China.
authors.forename: Junsheng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Gaobeidian Center for Disease Control and Prevention, Gaobeidian, Hebei Province 074000, PR China.
authors.forename: Haipo
authors.initials: H
authors.lastname: Wang
authors.affiliation: National Institute for Communicable Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, P.O. Box 5, Changping, Beijing 102206, PR China. Electronic address: shaozhujun@icdc.cn.
authors.forename: Zhujun
authors.initials: Z
authors.lastname: Shao
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood*; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D002681:China; D003430:Cross-Sectional Studies; D004166:Diphtheria Antitoxin / Q000097:blood*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage*; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D013743:Tetanus Antitoxin / Q000097:blood*; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D004166:Diphtheria Antitoxin; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines; D007074:Immunoglobulin G; D013743:Tetanus Antitoxin
keywords: China; Cross-sectional study; Diphtheria and tetanus; Seroprevalence