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Interchangeability of 2 diphtheria-tetanus-acellular pertussis vaccines in infancy
David P Greenberg1, Larry K Pickering, Shelly D Senders
1University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15213-2583, USA. greenbd@chplink.chp.edu
Insights
Using mixed diphtheria-tetanus-acellular pertussis (DTaP) vaccines in infants is safe and effective. Combining Tripedia and Infanrix vaccines for the primary immunization series showed similar safety and immunogenicity compared to using a single vaccine.
Area of Science:
- Pediatric immunology
- Vaccinology
- Public health
Background:
- Four diphtheria-tetanus-acellular pertussis (DTaP) vaccines are licensed in the US, with two commercially available.
- While a single DTaP vaccine is recommended for the primary series, infants may receive doses from different manufacturers.
- This study addresses the safety and immunogenicity of using mixed DTaP vaccine sequences.
Purpose of the Study:
- To evaluate the safety and immunogenicity of a mixed sequence of two different DTaP vaccines in infants.
- To compare the outcomes of mixed DTaP vaccine schedules with a single-manufacturer schedule.
Main Methods:
- A multicenter, observer-blinded, controlled study involving 449 infants.
- Infants were randomized into three groups: a control group receiving Tripedia for all three doses, and two experimental groups receiving mixed sequences of Tripedia and Infanrix.
- Safety was monitored closely, and antibody concentrations were measured using enzyme immunoassays.
Main Results:
- Injection-site and systemic adverse event rates were similar across all groups, with no significant differences.
- Infants in all groups demonstrated robust responses to DTaP antigens, achieving 97%-100% seroprotection after the primary series.
- Mixed-sequence DTaP vaccination schedules were found to be as immunogenic, or more so, than the control schedule.
Conclusions:
- Administering a mixed sequence of DTaP vaccines, specifically initiating with Tripedia and completing with Infanrix, is a safe and effective immunization strategy.
- This approach provides comparable or superior immunogenicity to using a single DTaP vaccine for the entire primary series.
Objective:
Currently, 4 diphtheria-tetanus-acellular pertussis (DTaP) vaccines are licensed for pediatric use in the United States, and 2 are commercially available. Although a single manufacturer's DTaP vaccine should be used for all 3 doses of the primary immunization series, some circumstances result in infants receiving DTaP vaccines from more than 1 manufacturer. The purpose of this study was to evaluate the safety and immunogenicity of a mixed sequence of 2 different DTaP vaccines.
Methods:
In this multicenter, observer-blinded, controlled study, 449 infants were randomized into 1 of 3 groups (1:1:1 ratio) to receive Tripedia at 2, 4, and 6 months of age (control group); Tripedia at 2 and 4 months of age and Infanrix at 6 months of age; or Tripedia at 2 months and Infanrix at 4 and 6 months of age. Other vaccines were administered concurrently as separate injections according to the recommended childhood immunization schedule. Safety was monitored closely, and standard enzyme immunoassays were used to measure antibody concentrations to each antigen of the DTaP vaccines.
Results:
The rates of injection-site and systemic adverse events were similar in each study group, and there were no clinically significant differences among groups after any dose. Infants in all 3 groups responded well to each antigen contained in both vaccines, with 97% to 100% seroprotection or vaccine response rates after the 3-dose primary series. Postvaccination geometric mean antibody concentrations and seroprotection or vaccine response rates to nearly all vaccine antigens were as high or higher in the mixed-sequence groups as in the control group.
Conclusion:
Initiating the primary immunization series with 1 or 2 doses of Tripedia and completing the 3-dose series with Infanrix is as safe and at least as immunogenic as administering Tripedia for all 3 doses.