Bovine TB cattle vaccine and skin test target date delayed

A deployable cattle vaccine and associated diagnostic test for bovine TB has been delayed by a few years, raising fears that the benefits of badger culling could soon be lost.

Defra had previously announced that the CattleBCG vaccine and the companion skin test to detect infected animals among vaccinated animals, known as the “Diva” test, was on course to be commercially available in 2025.

But following questioning from Farmers Weekly, Defra has admitted there is slippage in the timetable for the introduction of these important new tools.

See also: Badger culling policy reduces cattle TB by 56%, study shows

Defra and devolved administrations now aim to have a deployable cattle vaccine and the Diva test available “in the next few years”.

But this will depend on multiple steps, including the completion of field trials of the candidate CattleBCG vaccine and Diva test, and necessary authorisations.

Hurdles to overcome

Final deployment will rely on the success of the ongoing field trials, which started in 2021 on livestock farms in England and Wales, and achieving UK marketing authorisations from the Veterinary Medicines Directorate (VMD) for the CattleBCG vaccine and Diva test. 

To enable international trade in vaccinated cattle, approval from the World Organisation of Animal Health (WOAH), will also be required.

Defra has not divulged the reasons for the slippage. But sources have told Farmers Weekly it relates to new data emanating from the Diva test in field trials.

Intensive badger culling in England is being phased out in favour of vaccination, of both cattle and badgers, in the government’s revised approach to controlling TB in cattle, despite recent peer-reviewed analysis by Birch et al of Defra’s badger control policy in England which revealed a 56% fall in bovine TB rates.

But farm leaders are concerned that the benefits of the farmer-led badger culling programme will be lost if culling is removed without a viable alternative for disease control already in place.

One industry source said: “Now that we have already stopped culling and supplementary culling in some areas, we are already losing ground.

“A cattle vaccine is not coming any time soon, so if Defra does not deploy a decent epi-culling strategy, we are going to go back to where we were.”

Defra insists vaccinating cattle against TB will be a valuable addition to the toolbox, but does not aim to replace existing control measures.

Maintaining biosecurity measures on farm, avoiding risky movements of cattle and complying with testing protocols remain as important as ever in the fight against bovine TB, the department says.

Defra statement

A Defra spokesperson said: “Developing a deployable cattle bovine TB vaccine is one of the government’s top priorities. 

“We are committed to working at pace but will only deploy the vaccine when we have all the right steps in place to enable vaccination to be delivered effectively.”

Farmers Weekly contacted Prof James Wood, a TB expert from Cambridge University, who said “exciting new information is coming soon from the very positive results of testing BCG in cattle in Ethiopia”.