Related Experiment Videos
Persistence of protection through 33 months of age provided by immunization in infancy with two three-component
S Salmaso1, P Mastrantonio, S G Wassilak
1Laboratory of Epidemiology and Biostatistics, Istituto Superiore di Sanità, Rome, Italy. Salmaso@net.iss.it
Insights
Two diphtheria, tetanus, and acellular pertussis (DTaP) vaccines showed high efficacy in infants. The Chiron Biocine vaccine demonstrated slightly higher overall protection against pertussis compared to the SmithKline Beecham vaccine.
Area of Science:
- Pediatric infectious diseases
- Vaccinology
- Clinical immunology
Background:
- Pertussis (whooping cough) remains a significant public health concern globally.
- Infant vaccination with diphtheria, tetanus, and acellular pertussis (DTaP) vaccines is crucial for disease prevention.
- Evaluating the long-term efficacy and comparative effectiveness of different DTaP vaccine formulations is essential.
Purpose of the Study:
- To compare the efficacy of two three-component DTaP vaccines manufactured by SmithKline Beecham (SB) and Chiron Biocine (CB) in infants.
- To assess the sustained protective effect of these vaccines over an extended follow-up period.
- To determine the relative risk of pertussis between recipients of the two DTaP vaccines.
Main Methods:
- A large, randomized, placebo-controlled clinical trial conducted in Italy.
- Infants received either SB DTaP or CB DTaP vaccine.
- Participants were followed for an average age of 24 months, with an additional 9 months of observation for efficacy assessment.
- Pertussis was defined by clinical symptoms (paroxysmal cough ≥21 days) confirmed by culture or serology.
Main Results:
- Both SB DTaP and CB DTaP vaccines demonstrated 84% efficacy through 24 months of age.
- In the additional 9 months, observed absolute efficacy was 78% for SB DTaP and 89% for CB DTaP.
- The relative risk of pertussis was higher in SB DTaP recipients (1.99) compared to CB DTaP recipients.
- Overall efficacy through 33 months was 80% for SB DTaP and 85% for CB DTaP.
Conclusions:
- Both DTaP vaccines provide substantial protection against pertussis in infancy.
- The Chiron Biocine DTaP vaccine showed a trend towards higher sustained efficacy and lower risk of pertussis compared to the SmithKline Beecham vaccine.
- Continued surveillance and comparative studies are important for understanding vaccine performance over time.
Abstract:
A large, randomized, placebo-controlled clinical trial in Italy on two three-component pertussis vaccines, given as DTaP in infancy, one manufactured by SmithKline and Beecham (SB) and one by Chiron Biocine (CB), found each vaccine to be 84% efficacious through the average age of 24 months. The cohort of children enrolled in the trial was followed with unmodified case ascertainment procedures for nine additional calendar months, during which partial unblinding occurred, for the unvaccinated randomized group. For the DTaP groups, the specific vaccine assignment remained double-blinded throughout the entire additional observation period. Pertussis was defined as paroxysmal cough lasting at least 21 days and confirmed by culture or serology. In the additional 9 months the observed absolute efficacy was 78% (95% CI, 62-87%) for SB DTaP vaccine and 89% (95% CI, 79-94%) for CB DTaP. The relative risk of developing pertussis in SB DTaP recipients compared to CB DTaP vaccinees was 1.99 (95% CI, 1.13-3.51). By combining observations from the initial and additional follow-up periods, the overall observed vaccine efficacy through an average age of 33 months of SB DTaP was 80% and of CB DTaP, 85%.