The current supply of Equip Artervac has an expiry date of 29 March 2023 and due to supply issues Zoetis are not expecting a new batch to be available until the end of September 2023 meaning that all previously vaccinated stallions may go beyond the 6 month booster interval and therefore go ‘out of date’. It has been estimated that approximately 160 stallions may be affected by this. As there should be no issues in obtaining vaccine up to the date of expiry of the current batch of Artervac, it should be possible to bring vaccinations forward up to and before the 29 March 2023, making them next due for booster vaccination by 29 September 2023.
A prospective strategy is in place to monitor stallions by serological screening. Blood should be collected 2-3 weeks after the stallion receives it’s Artervac booster, when peak antibody levels should be present. This sample should be submitted to Rossdales laboratory, Newmarket, using the special submission form. A further blood sample should be taken at the time that the stallion receives their next Artervac booster when the new batch of vaccine is available. Paired serological testing will be performed to demonstrate that infection has not occurred and these results should be certified in the stallion’s passport. DEFRA’s Animal Disease Policy Group (ADPG) have approved the proposed approach for blood testing however, this strategy will only work if blood is taken in the proposed window post vaccination to provide a reference point for the paired serology. Stallions that do not follow this strategy will likely need a rely on a retrospective approach involving screening of semen for EAV to demonstrate they are free from infection before vaccination resumes. Stallions that were not sampled after they were last vaccinated could be boosted early on or before the 29 March 2023, and then sampled 2-3 weeks later.