Consistency testing of diphtheria and tetanus to replace potency testing for lot release

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Diphtheria and tetanus vaccines are highly effective and safe within the Expanded Programme on Immunization (EPI).
• Toxin-neutralizing antibodies are accepted correlates of protection, yet standardized potency testing for lot release remains a challenge.
• Current methods often involve animal testing, posing ethical and financial barriers.

Purpose of the Study:

• To address the lack of standardized potency testing for diphtheria and tetanus vaccines.
• To propose and update on the World Health Organization's (WHO) consistency approach for routine vaccine lot release.
• To leverage recent clinical trial data for combination vaccines to validate this new approach.

Main Methods:

• The study discusses the WHO's proposed harmonization of potency testing into simplified consistency tests.
• This approach relies on demonstrating biochemical and immunological consistency compared to clinically validated lots.
• It utilizes existing and upcoming clinical safety and efficacy data from combination vaccines.

Main Results:

• The consistency approach aims to replace traditional animal-based potency tests.
• It offers a more ethical and potentially cost-effective alternative for vaccine lot release.
• Leveraging new combination vaccine data provides an opportunity to validate this method.

Conclusions:

• The proposed WHO consistency approach offers a viable alternative for routine lot release of diphtheria and tetanus vaccine components.
• This method aligns with established clinical safety and efficacy, and manufacturing consistency.
• It presents a timely opportunity to improve vaccine quality control processes.