Establishment of hepatitis A virus coating reagent batch 2 for in vitro potency assay of hepatitis A vaccines by ELISA

The European Pharmacopoeia (Ph. Eur.) prescribes that hepatitis A vaccine (HAV) batches be tested for their potency before being released onto the European market. An enzyme-linked immunosorbent assay (ELISA) method for determination of antigen content of HAV was validated through an international collaborative study in 2012. This method requires specific coating and detection antibodies, i.e. coating reagent and detection antibodies Biological Reference Reagents (BRRs). The current batch of hepatitis A virus coating reagent (batch 1) was established in 2012. Stocks of this BRR were running low and a replacement batch was needed. Therefore, the European Directorate for the Quality of Medicines & HealthCare (EDQM) organised a collaborative study to qualify a replacement batch. Candidate coating reagent batch 2 was prepared from the same starting material as batch 1 and compared to the previous batch during the collaborative study. Results confirmed that candidate coating reagent batch 2 is suitable to be used for the intended purpose. The study demonstrated that batch 2 is comparable to batch 1 and that it can be used at the same working concentration, i.e. 1:500. The candidate material was adopted as Ph. Eur. Hepatitis A virus Coating Reagent for ELISA BRR batch 2 by the Ph. Eur. Commission at its 177th session in November 2023. It will be available from the EDQM under catalogue number Y0001624 once batch 1 is exhausted.