The Bultavo-3 vaccine offering active immunisation of sheep and cattle to reduce viraemia and to prevent clinical signs and mortality caused by bluetongue virus serotype 3 looks set to require annual administration to maintain immunity.

Speaking at last week’s Teagasc National Sheep Conference, Dr Ruth Sanders, superintending veterinary inspector with the Department of Agriculture, said that manufacturers of the vaccine, Boehringer Ingelheim, “have told us they have submitted all the necessary data to the competent authorities and are looking for a full year duration so it should be an annual vaccination”.

The current product characteristics listed by both the Health Products Regulatory Authority (HPRA) and the UK’s Veterinary Medicines Directorate list the duration of immunity as not established.

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This is currently the case with the two other vaccines approved for use in Ireland and the UK – namely Bluevac-3 and Syvazul BTV 3.

For Bultavo-3, sheep require one shot of the vaccine to build immunity after a period of three weeks while cattle require an initial shot followed by a booster three weeks later.

Vaccination reduces viraemia and clinical signs

It is probable that cattle that have received a full primary course will only require an annual booster vaccine.

Dr Sanders advised over 200 farmers in attendance to consider vaccinating animals. She said that it is impossible to tell what the prevalence of the virus and severity of disease will be in 2026.

She highlighted high levels of mortality in continental EU countries and said that while farmers in England and Wales and cases to date in Ireland have not displayed the same clinical symptoms of disease there is significant fertility issues being reported in England.

“Vaccination reduces viraemia and clinical signs and is the best tool we have in mitigating risk against the disease.”