title: Immunogenicity of heptavalent conjugate vaccine against Streptococcus pneumoniae in premature babies with low birth weight.
abstract: BACKGROUND
  There are few studies about immunogenicity and safety of heptavalent pneumococcal-CRM197 conjugate vaccine (PCV7) in low birth weight infants.
  
  
  OBJECTIVE
  Assessment of immunogenicity following administration of PCV7 in low birth weight children.
  
  
  METHODS
  The PCV7 vaccine was administered to 60 infants divided into two groups: 23 children with birth weight <1000 g (Group I); and 37 children with birth weight ≥1000 g (Group II). Serum was collected four times.
  
  
  RESULTS
  Birth weight of children included in the study ranged from 480 g to 2450 g. The primary immunization caused an increase in the average concentration of antibodies for all serotypes in most of the participants, with no significant differences between the groups. However, there were some differences between various serotypes. Group serotypes 6B and 23F were the least immunogenic (≥0.35 μg/mL, Group I vs. Group II - 6B: 78.3% vs. 67,6% p = 0.371 and 23F: 87% vs. 83.8% p = 0.738). Prior to the administration of a booster dose, a significant decrease in antibody titer was observed in all children. The last vaccination resulted in an increased concentration of antibodies in all children in both groups, and the results were significantly higher compared to those measured following administration of three doses of the vaccine.
  
  
  CONCLUSIONS
  PCV7 is immunogenic in children with low, very low, and extremely low birth weight. Serotypes 6B and 23F were the least immunogenic, and serotype 14 proved to be the most immunogenic.
authors.affiliation: Department of Paediatric Propaedeutics and Metabolic Bone Diseases of Medical University of Lodz, Poland. Electronic address: eszynczewska@gmail.com.
authors.forename: Ewa
authors.initials: E
authors.lastname: Szynczewska
authors.affiliation: Department of Paediatric Propaedeutics and Metabolic Bone Diseases of Medical University of Lodz, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Chlebna-Sokół
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007230:Infant, Low Birth Weight; D007234:Infant, Premature; D008297:Male; D022242:Pneumococcal Vaccines / Q000276:immunology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000276:immunology*; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines
keywords: Streptococcus pneumoniae; adverse events; immunogenicity; low birth weight; pneumococcal-CRM197 conjugate vaccine; prematurity