Rabies vaccines for veterinary use: difficulties in establishing potency acceptability thresholds

Area of Science:

• Veterinary immunology
• Biological assay validation

Background:

• Assessing biological test variability is challenging.
• Variability is a fundamental aspect of biological testing, exemplified by rabies vaccine control tests like the NIH or PER test.
• A single acceptability threshold is commonly used by producers and control laboratories.

Purpose of the Study:

• To address the challenges of biological test variability in quality control.
• To propose a framework for setting appropriate 'working acceptability thresholds' for biological products.
• To enhance collaboration and transparency between vaccine producers and control laboratories.

Main Methods:

• Analysis of variability in biological control tests.
• Review of existing acceptability threshold practices for veterinary vaccines.
• Discussion of statistical interpretation methods for control tests.

Main Results:

• Biological variability requires producers to establish a higher 'working acceptability threshold' than the official one.
• This safety margin helps ensure most vaccine batches pass official control.
• Control laboratories should provide flow charts and error margins to producers.

Conclusions:

• Producers must account for test variability by setting a higher working threshold.
• Control laboratories should increase transparency and reduce uncertainty in their tests.
• Accurate statistical interpretation by control labs allows producers to set more realistic working thresholds.