Safety and immunogenicity of diphtheria, tetanus and pertussis (acellular, three components) combined vaccine, adsorbed after three-dose priming in 2 months age infants: a randomized, blinded, controlled phase III clinical trial in China.
Wei Zhang, Chen Wei, Peng Wan et al.
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In 30 seconds
This randomized, blinded, controlled phase III trial compared a three-component acellular pertussis combination vaccine (DTcP) on two infant schedules with licensed DTaP-IPV-Hib in 1,380 healthy 2-month-old infants in China. Total adverse reactions were 14.52% and 16.59% with DTcP schedules versus 16.91% with the comparator (P = 0.183). The 2/4/6-month DTcP schedule produced higher geometric mean concentrations for pertussis toxoid and filamentous hemagglutinin than the comparator (84.23 vs. 65.35 and 132.16 vs. 102.13, respectively; both P < 0.001), with comparable diphtheria and tetanus responses.
Key findings
- Total adverse reactions were 14.52% and 16.59% with DTcP versus 16.91% with DTaP-IPV-Hib (P = 0.183).
- With the 2/4/6-month schedule, anti-PT geometric mean concentration was 84.23 vs. 65.35 and anti-FHA was 132.16 vs. 102.13; both P < 0.001.
- The 2/4/6-month schedule had less swelling (2.59% vs. 4.83%, P = 0.008) and irritability (0.07% vs. 1.02/1.40%, P < 0.001).
- DTcP elicited comparable diphtheria and tetanus responses to the comparator.
Why it matters
The trial provides comparative safety and antibody-response data for a three-component acellular pertussis vaccine in young infants, including two primary schedules. The stronger measured pertussis-antigen responses with the 2/4/6-month schedule may inform further evaluation of infant vaccination strategies amid pertussis resurgence, while antibody outcomes alone do not establish protection against clinical disease.
What to keep in mind
The abstract reports immunogenicity outcomes 30 days after primary vaccination; it does not provide evidence here about longer-term protection or clinical pertussis outcomes.