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Pertussis antibody levels in infants immunized with an acellular pertussis component vaccine, measured using
M Hanlon1, R Nambiar, A Kakakios
1Department of Immunology and Infectious Diseases, New Children's Hospital, Westmead, New South Wales, Windsor, Queensland, Australia. markh@nch.edu.au
Insights
A whole-cell pertussis IgG ELISA effectively measures infant immune response to acellular pertussis vaccines. Most infants show increased antibody levels post-immunization, indicating vaccine efficacy.
Area of Science:
- Immunology
- Vaccinology
Background:
- Infant immunization schedules rely on effective vaccines.
- Assessing immune response to acellular pertussis vaccines is crucial.
Purpose of the Study:
- To evaluate the utility of a whole-cell pertussis IgG ELISA in assessing infant immune responses to a trivalent acellular pertussis vaccine.
- To determine seroconversion rates and antibody index changes post-vaccination.
Main Methods:
- A commercially available whole-cell pertussis IgG ELISA was employed.
- 137 two-month-old infants received a trivalent acellular pertussis vaccine.
- Pre- and post-immunization IgG indices were measured.
Main Results:
- Post-immunization geometric mean IgG index significantly increased (P < 0.001).
- 80% of infants showed a significant increase in pertussis IgG index or a post-immunization index > 10.
- High pre-immunization antibody levels correlated with a smaller increase in IgG index.
Conclusions:
- The whole-cell pertussis IgG ELISA is a viable method for detecting immune responses to acellular pertussis vaccines in infants.
- Calculating both antibody index and seroconversion degree enhances detection accuracy.
- Most infants demonstrate a robust immune response to the acellular vaccine.
Abstract:
A commercially available whole-cell pertussis IgG ELISA was used to test the response of 137 2-month-old infants to immunization with a trivalent acellular pertussis vaccine. The pre-immunization geometric mean (GM) IgG index was 6.96 (95% confidence interval (CI) 5.88-8.04) and the postimmunization GM index was 13.16 (95% CI 12. 20-14.11), P < 0.001. Eighty percent of subjects (110/137) had a significant 1.5-fold increase of pertussis IgG index (97/137, 71%) or a postimmunization IgG index > 10 (93/137, 68%). In single antigen ELISA, 83% showed at least a fourfold increase in pertussis toxin-specific IgG (PT-IgG) and 91% showed an increase in IgG specific for filamentous haemagglutinin (FHA-IgG). Four percent had high pre- immunization antibody levels (index > 20), likely to reflect recent maternal exposure to pertussis. This correlated with a smaller increase in pertussis IgG index. A decline in pertussis IgG index postimmunization occurred in 17/24 infants (71%) whose pre-immunization IgG index was > 10. This postimmunization pertussis IgG index was not significantly different to that of infants with a low pre-immunization index. A similar trend was noted with PT-IgG and FHA-IgG results. The whole-cell ELISA can detect a response to acellular pertussis vaccination in most infants if both antibody index and degree of seroconversion are calculated and at least one criterion is satisfied.
