Appendix 24

CONCEPT NOTE

1. Proposal prepared by: Aldo Dekker 2. Short description of the background to issue or situation

For decades, it has been known that FMD vaccination is more effective when the vaccine contains 146S antigen instead of 12S antigen. In the past, sucrose density gradient analysis has been developed to measure the 146S antigen content; however, with these techniques it is not possible to measure 146S content in formulated vaccines.

The products division of ASG-Lelystad together with the Central Veterinary Institute in Lelystad have developed an assay to quantify the percentage of the total intact FMDV antigen in oilconjugated vaccines. This test is based on ELISA and not on sucrose density gradient. The percentage of intact particles of the A and O strains are detected by this test. No discrimination between these strains can be made. Details of the test will not be shared at this moment, because of confidentiality reasons.

In several countries where vaccination is applied, low antibody titres are found in animals vaccinated under field conditions, in several cases leading to outbreaks in vaccinated animals. This low antibody response and poor protection might be explained by degradation of the antigen to 12S.

3. Key bottlenecks/issues addressed

Stability of FMD vaccines used with the support of FAO will be tested. 4. Proposed action

The test has been developed using oil adjuvanted FMDV vaccine, but will probably also work for

Al(OH)3 adjuvanted FMDV vaccines. The physical and chemical characteristics of this vaccine are most likely different from the vaccines that will be tested in this study vaccine. Therefore, a feasibility test will be performed upon receipt of the vaccines. The percentage of the intact virions present in the vaccines will be measured. When doubtful results are obtained or when all intact virions are already degraded, the study will be terminated.

With a successful feasibility test result, vaccines will be measured according to the above described test. The vaccines will be stored at 4°C, 20 °C and 30 °C up to 2 weeks and subsequently tested.

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Time point 0 1 day 2 days 4 days 7 days 14 days 4 °C X X X X X X 20 °C X X X X X X 30 °C X X X X X X

Report

The results will be detailed in a report and sent for approval. 5. Budget estimate:

The cost of testing will depend on the number of vaccines tested and how often vaccines will be tested. An initial budget of € 10k will be sufficient to perform the experiment once with a limited set of vaccines.

6. What to recommend

Stability of FMD vaccines is a very important issue in control of FMD outbreaks by vaccination. Initial testing various vaccines will provide additional information on the FMDV vaccines tested and the validity of the test method. In the future this test could be used as a standard method to evaluate vaccines bought with EC or EUFMD money next to standard production of 3 – 4 week postvaccination sera in 10 seronegative cattle.

7. Further information on the matter

The test developed is Intellectual property of the products division of ASG-Lelystad. At this moment it is not possible to give information on the validation data of the test. Most likely some data will be presented at the next Research Group session in Sicily. The information in this proposal should be kept confidential and should not be shared with other FMDV vaccine producers.

76th Session of the Executive Committee of the European Commission for the Control of Foot-and-Mouth Disease