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Evaluation of the pertussis components of diphtheria-tetanus-pertussis vaccine
Insights
The diphtheria-tetanus-pertussis (DTP) vaccine's whole cell pertussis antigen combined with aluminum phosphate adjuvant caused more severe local and febrile reactions, suggesting a suboptimal formulation.
Area of Science:
- Immunology
- Vaccine Development
- Public Health
Background:
- The pertussis component of the diphtheria-tetanus-pertussis (DTP) vaccine is crucial for preventing whooping cough.
- Different formulations of the DTP vaccine exist, varying in their pertussis antigen (whole cell or extracted) and adjuvant (aluminum phosphate or alum) components.
- Understanding the impact of these components on vaccine safety and immunogenicity is essential for optimizing DTP vaccine efficacy.
Purpose of the Study:
- To evaluate the adjuvant and antigen components of the pertussis fraction of the DTP vaccine.
- To compare the safety and immunogenicity of four DTP vaccine preparations with different antigen and adjuvant combinations.
- To determine the optimal formulation for the pertussis component of the DTP vaccine.
Main Methods:
- Four DTP vaccine preparations were created using either whole cell (Wc) or extracted (E) pertussis antigen.
- These antigens were combined with either aluminum phosphate (Ph) or alum (Al) adjuvant.
- Local reactions, febrile reactions, and serologic responses (geometric mean titer) were compared across the four vaccine groups.
Main Results:
- The whole cell pertussis antigen combined with aluminum phosphate adjuvant (WcPh) showed significantly increased local reactions after the third immunization.
- The WcPh vaccine also resulted in more frequent and higher fevers after the first immunization, attributed to the whole cell component.
- While pooled whole cell groups showed a greater febrile response, serologic responses were not significantly different among individual vaccines, though Wc antigen produced a higher geometric mean titer.
Conclusions:
- Local and febrile reactions appear to be distinct, with adjuvants influencing local reactions and whole cell components influencing febrile responses.
- The combination of whole cell pertussis antigen and aluminum phosphate adjuvant, currently used in the United States, may not be the optimal DTP vaccine formulation.
- Further research into DTP vaccine components is warranted to improve safety and immunogenicity profiles.
Abstract:
The adjuvant and antigen components of the pertussis fraction of diphtheria-tetanus-pertussis (DTP) vaccine were evaluated. Four preparations of DTP vaccine composed of either whole cell (Wc) or extracted (E) pertussis antigen combined with either an aluminum phosphate (Ph) or alum (Al) adjuvant were compared. Local reactions were similar in all four vaccines after the first two immunizations but were significantly increased in incidence and severity following the third immunization with vaccine WcPh. This appeared to be due to the Ph adjuvant rather than the antigen component. Febrile reactions were experienced more often (P = .0009) and with higher temperatures (P = .0001) with the WcPh vaccine following the first immunization. This appeared to be due to the Wc component. Comparing the pooled Wc groups with the pooled E groups revealed a greater febrile response in the Wc group after both the first (P = .0008) and the second (P = .03) immunization. Local reactions appear temporally and etiologically to be distinct from febrile reactions. The pooled Wc antigen group produced a higher geometric mean titer than the pooled E antigen group (P = .05). Serologic responses, with respect to geometric mean titer, were not significantly different among the individual vaccines. This study suggests that the combination of whole cell and aluminum phosphate, which is currently in use in the United States, is probably not the optimal formulation for pertussis vaccine.