Unchanged efficacy of a pertussis toxoid vaccine throughout the two years after the third vaccination of infants.

Abstract

BACKGROUND:

In a previously reported double blind efficacy trial of a pertussis toxoid vaccine, 3450 infants were randomized to receive diphtheria-tetanus toxoids with or without pertussis toxoid at 3, 5 and 12 months of age. Efficacy against pertussis as defined by the World Health Organization was 71% from 30 days after the third vaccination with an average follow-up of 17.5 months. We now report efficacy for an additional 6 months of open follow-up.

METHODS:

Parents were contacted monthly by a nurse. If a participant or a family member coughed for > or = 7 days, a nasopharyngeal sample and paired sera were obtained.

RESULTS:

Efficacy during this open follow-up period was 77% (95% confidence intervals, 66 to 85%) based on 29 and 110 cases fulfilling the WHO definition of pertussis in vaccinated and control children, respectively. Efficacy against household exposure was 76% (95% confidence intervals, 51 to 91%). Pertussis in vaccinated children had a significantly shorter duration than pertussis in control children. Determination of pertussis toxin antibodies in paired sera with enzyme-linked immunosorbent assay had a lower diagnostic sensitivity in vaccinated (45%) than in control (92%) children, while determination of antibodies against filamentous hemagglutinin (not included in the vaccine) was highly sensitive for diagnosing pertussis in both groups (100 and 90%, respectively).

CONCLUSIONS:

A monocomponent pertussis toxoid vaccine induces significant protection against pertussis for at least 2 years after the third injection. To obtain an unbiased estimate of vaccine efficacy it is important to determine antibodies against an antigen that is not included in the vaccine.

• Authors: J Taranger, B Trollfors, T Lagergård, L Lind, V Sundh, G Zackrisson, D A Bryla, J B Robbins
• Journal: The Pediatric infectious disease journal (Pediatr Infect Dis J) Vol. 16 Issue 2 Pg. 180-4 (Feb 1997) ISSN: 0891-3668 [Print] United States
• PMID: 9041597 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Chemical References

• Antibodies, Bacterial
• Diphtheria Toxoid
• Diphtheria-Tetanus Vaccine
• Diphtheria-Tetanus-Pertussis Vaccine
• Tetanus Toxoid
• Toxoids
• Vaccines, Combined
• pertussis toxoid

Topics

• Antibodies, Bacterial (biosynthesis)
• Bordetella pertussis (immunology, isolation & purification)
• Child, Preschool
• Cohort Studies
• Diphtheria Toxoid (administration & dosage, immunology)
• Diphtheria-Tetanus Vaccine
• Diphtheria-Tetanus-Pertussis Vaccine (administration & dosage, immunology)
• Follow-Up Studies
• Humans
• Immunization Schedule
• Infant
• Nasopharynx (microbiology)
• Polymerase Chain Reaction
• Randomized Controlled Trials as Topic
• Tetanus Toxoid (administration & dosage, immunology)
• Toxoids (immunology)
• Vaccination
• Vaccines, Combined (administration & dosage, immunology)