title: Type-specific antibodies to pneumococcal capsular polysaccharide acquired either naturally or after vaccination with Prevenar in children with underlying chronic or recurrent lung diseases.
abstract: The antibody response to capsular polysaccharides of pneumococcal serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F elicited either naturally or after vaccination with Prevenar was investigated in a cohort of children (n = 163) with underlying chronic or recurrent lung diseases at risk of developing pneumococcal pneumonia and ultimately invasive disease. Serum concentrations of serotype-specific antibodies, as measured by enzyme-linked immunosorbent assay, in unvaccinated children (n = 88) were higher in nasopharyngeal carriers (n = 10) than in noncarriers (n = 78) both at baseline and during follow-up. However, the antibody levels depended on the serotype and age of the children. During the study period, 35% of unvaccinated noncarriers and 60% of unvaccinated carriers displayed serum antibodies to all serotypes above the reported WHO working group putative protective serum concentration against invasive disease (0.2 mug/ml). Overall, children vaccinated with Prevenar before enrollment (n = 61), irrespective of their carrier status, displayed significantly higher serum levels of antibodies to all serotypes than unvaccinated children. More than 85% of the vaccinated children had protective serum antibody concentrations at baseline; although antibody titers tended to decrease over time, the above-mentioned figure remained without change at the end of follow-up. The vaccine Prevenar elicited a significant rise in serum antibody concentrations against all serotypes in 14 children vaccinated at entry. All of these children acquired and maintained serum antibody levels of >0.2 microg/ml throughout the study (a mean of 13 months of follow-up). These data support the systematic use of the vaccine Prevenar in children with underlying chronic or recurrent lung diseases and stress the fact that a percentage of vaccinated children may need to be revaccinated in order to achieve protection against pneumococcal disease.
authors.affiliation: Department of Microbiology, University Clinical Hospital, Av. Blasco Ibáñez 17, 46010 Valencia, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Navarro
authors.forename: Amparo
authors.initials: A
authors.lastname: Escribano
authors.forename: Laura
authors.initials: L
authors.lastname: Cebrián
authors.forename: Concepción
authors.initials: C
authors.lastname: Gimeno
authors.forename: Leonor
authors.initials: L
authors.lastname: García-Maset
authors.forename: Juan
authors.initials: J
authors.lastname: García-de-Lomas
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000032:analysis / Q000096:biosynthesis*; D000918:Antibody Specificity / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D008171:Lung Diseases / Q000276:immunology* / Q000517:prevention & control*; D008297:Male; D022401:Meningococcal Vaccines / Q000276:immunology / Q000627:therapeutic use*; D022242:Pneumococcal Vaccines / Q000276:immunology / Q000627:therapeutic use*; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D018709:Statistics, Nonparametric; D014611:Vaccination / Q000379:methods*
chemical_list: D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial; C027158:polysaccharide C-substance (Streptococcus)