title: Levels and functionality of antibodies after pneumococcal conjugate vaccine in schedules with different timing of the booster dose.
abstract: The seven-valent pneumococcal conjugate vaccine (PCV7) has been introduced in most high-income countries, although with differences in age, timing and number of primary doses before 6 months of age and presence and timing of a booster vaccination. The objective was to determine and compare the IgG antibody levels and functionality of IgG responses (avidity and opsonophagocytoses) at 1 and 2 years of age following 2 primary doses with a booster at 11 or 24 months of age. Children received PCV7 at 2 and 4 months (2-dose group), or at 2, 4 and 11 months (2+1-dose group), or no PCV7 (controls) before 1 year of age. All children received a PCV7 dose at 24 months of age. At the age of 12 months, the 2+1-dose group had higher IgG levels and functional antibody levels, compared to the 2-dose group for all serotypes, but at 25 months the difference between the 2-dose and 2+1-dose groups had disappeared for most serotypes. The kinetics of opsonophagocytic antibodies were in line with the specific IgG antibody levels for most serotypes, although differences between the 2-dose and the 2+1-dose group were more pronounced in OPA activity as compared to the IgG levels especially at the age of 24 months. Delaying the booster dose from 11 months to 24 months after 2 primary doses resulted in significantly higher OPA GMTs one month after the booster dose. This must, however, be balanced against the risk of leaving children unboosted between the age of 11 and 24 months at a time when disease risk is still high. Local decisions about the timing of a booster dose should also take into account vaccine coverage and the indirect herd effect in a well vaccinated population. Trial registration clinicaltrials.gov Identifier: NCT00189020.
authors.affiliation: Centre for Immunology of Infectious Diseases and Vaccines, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: Els
authors.initials: E
authors.lastname: van Westen
authors.forename: Gerwin D
authors.initials: GD
authors.lastname: Rodenburg
authors.forename: Elske J M
authors.initials: EJ
authors.lastname: van Gils
authors.forename: Irina
authors.initials: I
authors.lastname: Tcherniaeva
authors.forename: Guy A M
authors.initials: GA
authors.lastname: Berbers
authors.forename: Lucy
authors.initials: L
authors.lastname: Cowell
authors.forename: David
authors.initials: D
authors.lastname: Goldblatt
authors.forename: Nynke Y
authors.initials: NY
authors.lastname: Rots
authors.forename: Germie P J M
authors.initials: GP
authors.lastname: van den Dobbelsteen
authors.forename: Elisabeth A M
authors.initials: EA
authors.lastname: Sanders
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood* / Q000276:immunology; D000915:Antibody Affinity; D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007223:Infant; D009895:Opsonin Proteins / Q000097:blood / Q000276:immunology; D010587:Phagocytosis; D011008:Pneumococcal Infections / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D016037:Single-Blind Method; D018074:Vaccines, Conjugate / Q000008:administration & dosage
chemical_list: D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G; D009895:Opsonin Proteins; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate
keywords: Avidity; Booster vaccination; Opsonophagocytosis; PCV7; Pneumococcal conjugate vaccine; Streptococcus pneumoniae