Acellular pertussis vaccine given by accelerated schedule: response of preterm infants.
OBJECTIVE
To describe the immune response of preterm infants to a diphtheria/tetanus/three component acellular pertussis (DTaP) vaccine, under an accelerated schedule, and the effects of steroids on this response. To compare responses with those of term infants.


METHODS
Prospective observational study.


METHODS
Five Wessex neonatal units; Hertfordshire immunisation clinics.


METHODS
Infants born at < 32 weeks; term controls.


METHODS
DTaP-Haemophilus influenzae type b vaccine given at 2, 3, and 4 months. Blood taken to assess antibody responses to vaccines.


METHODS
IgG geometric mean concentrations (GMC) to vaccines.


RESULTS
A total of 130 preterm (mean gestational age 29.1 weeks) and 54 term infants were recruited. After the third immunisation, preterm infants had similar GMCs to controls to diphtheria, tetanus, filamentous haemagglutinin (FHA), and pertactin (PRN), but a significantly lower GMC to pertussis toxin (PT). Responses to tetanus and PRN increased with age at the third immunisation, and those to tetanus, FHA, PRN, and PT increased with gestational age at birth. Response to tetanus correlated negatively with the number of doses of antenatal steroids received. There was no association between responses and postnatal steroids.


CONCLUSIONS
When immunised with a combined acellular pertussis- H influenzae type b vaccine under an accelerated schedule, IgG GMC of preterm infants to PT was reduced. GMCs to tetanus, FHA, PRN, and PT increased with gestational age at birth, and GMCs to tetanus and PRN increased with age at the third immunisation. There is, however, no benefit in delaying immunisation. Anti-tetanus IgG decreased with increasing number of doses of antenatal steroids. There was no effect for postnatal steroids.
Slack
M H
MH
Department of Paediatrics, St Mary's Hospital, Portsmouth, UK. marts@doctors.org.uk
Schapira
D
D
Thwaites
R J
RJ
Schapira
C
C
Bamber
J
J
Burrage
M
M
Southern
J
J
Andrews
N
N
Miller
E
E
D000367:Age Factors; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology; D001724:Birth Weight; D004167:Diphtheria Toxin / Q000276:immunology; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005865:Gestational Age; D019741:Haemophilus influenzae type b / Q000276:immunology; D006388:Hemagglutinins / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007231:Infant, Newborn; D007234:Infant, Premature / Q000276:immunology*; D008297:Male; D037342:Pertussis Toxin / Q000276:immunology; D011295:Prenatal Care / Q000379:methods; D011446:Prospective Studies; D013256:Steroids / Q000627:therapeutic use; D013744:Tetanus Toxin / Q000276:immunology; D010566:Virulence Factors, Bordetella / Q000276:immunology
D001425:Bacterial Outer Membrane Proteins; D004167:Diphtheria Toxin; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines; D006388:Hemagglutinins; D007074:Immunoglobulin G; D013256:Steroids; D013744:Tetanus Toxin; D010566:Virulence Factors, Bordetella; C068929:pertactin; D037342:Pertussis Toxin