title: Safety, tolerability, and immunogenicity of 7-valent pneumococcal conjugate vaccine in older infants and young children in China who are naive to pneumococcal vaccination: Results of a phase 4 open-label trial.
abstract: BACKGROUND
  This postlicensure study was conducted to assess immunogenicity and safety of PCV7 catch-up regimens in previously unvaccinated older infants and young children in China.
  
  
  METHODS
  Healthy children 121 days to <72 months were grouped by age and immunized with 1 of 4 PCV7 dosing regimens. Serotype-specific IgG geometric mean concentrations (GMCs) and percentage of subjects with IgG≥0.35μg/mL were assessed before vaccination and 1 and 12 months postvaccination. The incidence of clinically important adverse events (AEs) and serious AEs (SAEs), AEs leading to study withdrawal, and protocol-related AEs were assessed throughout the study.
  
  
  RESULTS
  Prevaccination serotype-specific GMCs were generally low in subjects <24 months; the majority of children 24 to <72 months had IgG concentrations ≥0.35 μg/mL. One month postvaccination, GMCs were similar across groups for the 7 PCV serotypes, ranging from 3.95 to 13.02 μg/mL; the highest antibody levels were observed for serotype 14. Regardless of dosing regimen, >90% of subjects had IgG≥0.35 μg/mL for each PCV serotype. At 12-month follow-up, IgG GMCs ranged from 0.65 to 5.19, and all remained above prevaccination IgG GMC; >70% of subjects had IgG≥0.35 μg/mL. Older children generally had the most robust immune response both at 1 month postvaccination and during 12-month follow-up. PCV7 was well tolerated. Pyrexia, which was mild to moderate in severity, was the most common AE. Two subjects reported SAEs (n=4), and there was 1 study withdrawal; none of these were considered treatment related.
  
  
  CONCLUSIONS
  In China, PCV7 catch-up vaccinations given to older infants and young children naive to pneumococcal vaccines resulted in a robust immune response to all serotypes; this response persisted after 1 year. PCV7 was well tolerated in Chinese infants and children.
authors.affiliation: Guangxi Center for Disease Control and Prevention, Center for Vaccine Clinical Research, Nanning, Guangxi Province, China.
authors.forename: Rongcheng
authors.initials: R
authors.lastname: Li
authors.affiliation: Guangxi Center for Disease Control and Prevention, Center for Vaccine Clinical Research, Nanning, Guangxi Province, China.
authors.forename: Lirong
authors.initials: L
authors.lastname: Huang
authors.affiliation: Yongfu Center for Disease Control and Prevention, Yongfu, Guangxi Province, China.
authors.forename: Shunping
authors.initials: S
authors.lastname: Mo
authors.affiliation: Yongfu Center for Disease Control and Prevention, Board of Health, Yongfu, Guangxi Province, China.
authors.forename: Junchun
authors.initials: J
authors.lastname: Li
authors.affiliation: Pfizer Inc, Shanghai, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Pfizer Inc, Shanghai, China.
authors.forename: Zhangjing
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Pfizer Inc, Collegeville, PA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Liang
authors.affiliation: Pfizer Inc, Collegeville, PA, USA. Electronic address: mariano.young-jr@pfizer.com.
authors.forename: Mariano
authors.initials: M
authors.lastname: Young
authors.affiliation: Pfizer Inc, Pearl River, NY, USA.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Giardina
authors.affiliation: Pfizer Inc, Pearl River, NY, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Scott
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002681:China; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D064368:Healthy Volunteers; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D016896:Treatment Outcome; D014611:Vaccination / Q000009:adverse effects* / Q000379:methods*
chemical_list: D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G
keywords: Catch-up vaccination; Children; China; Infants; PCV7; S. pneumoniae