Collaborative study for the establishment of a candidate equine influenza subtype 2 American-like strain A/EQ/South Africa/4/03 – horse antiserum biological reference preparation.

The research article presents a collaborative study aimed at establishing a candidate equine influenza subtype 2 American-like strain A/EQ/South Africa/4/03 – horse antiserum biological reference preparation. This new reference was needed following a 2004 recommendation by the OIE Expert Surveillance Panel on equine influenza to update the American lineage component of equine influenza vaccines.

Background

• The research was prompted by the 2004 recommendation from the Office International des Epizooties (OIE) Expert Surveillance Panel on equine influenza. The panel proposed that the American lineage component (H3N8) of equine influenza vaccines be updated.
• The updated vaccine had to be based on an A/eq/South Africa/4/03-like virus, hence correlating reference for equine influenza subtype 2 American-like antiserum also needed to be complemented with an antiserum created against the A/eq/South Africa/4/03 strain.
• This triggered the need for this collaborative research organized by the European Directorate for the Quality of Medicines (EDQM) within its Biological Standardisation Programme (BSP) under the supervision of the European Pharmacopoeia (Ph. Eur.) and the OIE.

Objective and Methods

• The study aimed to evaluate a candidate reference horse anti-serum using single radial haemolysis (SRH) and haemagglutination inhibition (HI) tests.
• The aim was to establish the standard for use in immunogenicity and batch potency tests of equine influenza vaccines, and for use in clinical diagnostic tests.

Results and Conclusion

• The research allowed the suitability of the candidate to be demonstrated and an SRH value to be assigned. This means that the candidate was effective and met the required standards.
• The candidate was adopted as a Biological Reference Preparation by the Ph. Eur. Commission and approved by the OIE Biological Standard’s Commission as an International Standard Serum in June and September 2006, respectively.
• The successful establishment of this new standard not only complies with the OIE’s 2004 recommendation, but also provides a basis for testing the potency of equine influenza vaccines and aids in clinical diagnosis.