Antibody and cell-mediated immunity to pertussis 4 years after monovalent acellular pertussis vaccine at birth.
BACKGROUND
In a previous study, we found that monovalent acellular pertussis (aP) vaccine at birth and 1 month achieves higher IgG antibody (Ab) levels to pertussis toxoid (PT), filamentous hemagglutinin (FHA) and pertactin by 8 weeks, when compared with controls. Here, we report antibody and cell-mediated immune responses to 4 years of age.


METHODS
IgG Ab to PT, filamentous hemagglutinin and pertactin, diphtheria (D) and tetanus (T) was measured in the 3 groups (aP vaccine at birth and 1 month, aP birth only and no aP) at 2 years of age and before and after DTaP-inactivated polio vaccine (DTaP-IPV) at 4 years of age. Cell-mediated immune responses to pertussis vaccine antigens were measured at 2 years of age. Adverse events following DTaP-IPV were recorded.


RESULTS
Of 74 subjects, 52 (70%) were available for follow up. Overall, 11 (21%) had detectable PT IgG at 2 years, decreasing to 10% before 4-year-old booster compared with 100% at 8 months of age. After the 4-year booster, pertussis antigen IgG levels were similar, but there was a trend to lower PT IgG levels in birth aP infants (geometric mean concentrations: 28.7 EI.U/mL) compared with controls (geometric mean concentrations: 53.6 EI.U/mL). The cytokine responses to pertussis antigen stimulation were higher in aP recipients at 2 years of age. There was no difference in injection site reactions among groups following the DTaP-IPV booster at 4 years of age.


CONCLUSIONS
In the longest reported follow-up of infants who received aP vaccine at birth, we found a trend to lower PT IgG antibodies post booster compared with receipt of first dose of aP-containing vaccine at 8 weeks of age. Short- and long-term antibody responses with and without prior maternal pertussis vaccination are crucial for further evaluation of this strategy for preventing severe early pertussis.
From the *National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, The Children's Hospital at Westmead and the University of Sydney, New South Wales; †The Children's Hospital, Westmead, Sydney; ‡The University of Sydney, New South Wales, Australia; §Discipline of Paediatrics, School of Paediatrics and Reproductive Health and the Robinson Institute, The University of Adelaide; ¶Vaccinology and Immunology Research Trials Unit, Women's and Children's Hospital, Women's and Children's Health Network, South Australia; ‖Telethon Institute for Child Health Research and Centre for Child Health Research, Faculty of Medicine and Dentistry, The University of Western Australia, Perth; and **Queensland Children's Medical Research Institute, University of Queensland, Brisbane, Queensland, Australia.
Nicholas
N
Wood
Helen
H
Marshall
Olivia J
OJ
White
Patrick G
PG
Holt
Peter
P
McIntyre
D018829:Adhesins, Bacterial / Q000276:immunology; D000907:Antibodies, Bacterial / Q000097:blood*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology; D002675:Child, Preschool; D004167:Diphtheria Toxin / Q000276:immunology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010567:Pertussis Vaccine / Q000008:administration & dosage / Q000276:immunology*; D013744:Tetanus Toxin / Q000276:immunology; D013997:Time Factors; D014121:Toxoids / Q000276:immunology*; D010566:Virulence Factors, Bordetella / Q000276:immunology
D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D004167:Diphtheria Toxin; D007074:Immunoglobulin G; D010567:Pertussis Vaccine; D013744:Tetanus Toxin; D014121:Toxoids; D010566:Virulence Factors, Bordetella; C065273:filamentous hemagglutinin adhesin, Bordetella pertussis; C051093:pertussis toxoid; C068929:pertactin