Immunogenicity and safety of primary three-dose series with diphtheria, tetanus and pertussis (acellular, three components) combined vaccine, adsorbed in 3 months infants

This study aimed to evaluate the safety and immunogenicity of a novel diphtheria, tetanus, and pertussis (acellular, three components) combined vaccine, adsorbed (DTcP) vaccine compared to the existing co-purified DTaP vaccine in China. In this partially randomized, blinded, controlled Phase III trial, we assessed a DTcP vaccine against two controls: a licensed co-purified DTaP and a DTaP-IPV-Hib vaccine. A total of 1,140 infants (3 months old) received a 3-dose primary series at 3, 4, and 5 months. Both of DTcP and co-purified DTaP had lower incidences of overall adverse reactions than the DTaP-IPV-Hib vaccine (17.99%/18.08% vs. 21.96%). The DTcP vaccine demonstrated non-inferiority and superiority over the co-purified DTaP for anti-PT and anti-FHA immunogenicity. In addition, the DTcP achieved a 98.16% seroconversion rate for anti-FHA, versus only 14.29% for the co-purified DTaP. Besides, DTcP vaccine also induced high antibody level in GMC results. Specifically, the anti-PT GMC was 85.10 in the DTcP group versus 49.86 in the DTaP group (P < 0.001) and 74.25 in the DTaP-IPV-Hib (P = 0.001). For anti-FHA, the GMC was 108.28 in the DTcP group compared to only 10.69 in the DTaP group. In conclusion, DTcP vaccine induces a significantly more robust immune response to key pertussis antigens --compared to the co-purified DTaP, with a comparable safety profile. These data support the potential optimization of China's immunization strategy by transitioning from co-purified to component-based acellular pertussis vaccines to address waning immunity and the ongoing pertussis resurgence. ClinicalTrial.gov, identifier NCT05951725.