title: Systematic review of reporting rates of adverse events following immunization: an international comparison of post-marketing surveillance programs with reference to China.
abstract: BACKGROUND
  China is the most populous country in the world, with an annual birth cohort of approximately 16 million, requiring an average of 500 million vaccine doses administered annually. In China, over 30 domestic and less than 10 overseas vaccine manufacturers supply over 60 licensed vaccine products, representing a growing vaccine market mainly due to recent additions to the national immunization schedule, but data on post-marketing surveillance for adverse events following immunization (AEFI) are sparse.
  
  
  OBJECTIVE
  To compare reporting rates for various categories of AEFI from China with other routine post-marketing surveillance programs internationally.
  
  
  METHODS
  Systematic review of published studies reporting rates of AEFI by vaccine, category of reaction and age from post-marketing surveillance systems in English and Chinese languages.
  
  
  RESULTS
  Overall AEFI reporting rates (all vaccines, all ages) in Chinese studies were consistent with those from similar international studies elsewhere, but there was substantial heterogeneity in regional reporting rates in China (range 2.3-37.8/100,000 doses). The highest AEFI reporting rates were for diphtheria-tetanus-pertussis whole-cell (DTwP) and acellular (DTaP) vaccines (range 3.3-181.1/100,000 doses for DTwP; range 3.5-92.6/100,000 doses for DTaP), with higher median rates for DTwP than DTaP, and higher than expected rates for DTaP vaccine. Similar higher rates for DTwP and DTaP containing vaccines, and relatively lower rates for vaccines against hepatitis B virus, poliovirus, and Japanese encephalitis virus were found in China and elsewhere in the world.
  
  
  CONCLUSIONS
  Overall AEFI reporting rates in China were consistent with similar post-marketing surveillance systems in other countries. Sources of regional heterogeneity in AEFI reporting rates, and their relationships to differing vaccine manufacturers versus differing surveillance practices, require further exploration.
authors.affiliation: School of Population Health, The University of Queensland, Queensland, Australia. b.guo@uq.edu.au
authors.forename: Biao
authors.initials: B
authors.lastname: Guo
authors.forename: Andrew
authors.initials: A
authors.lastname: Page
authors.forename: Huaqing
authors.initials: H
authors.lastname: Wang
authors.forename: Richard
authors.initials: R
authors.lastname: Taylor
authors.forename: Peter
authors.initials: P
authors.lastname: McIntyre
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D002681:China; D006801:Humans; D007114:Immunization / Q000009:adverse effects*; D007115:Immunization Schedule; D007223:Infant; D007231:Infant, Newborn; D011358:Product Surveillance, Postmarketing; D014765:Viral Vaccines / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D001428:Bacterial Vaccines; D014765:Viral Vaccines