Field trials for bovine TB cattle vaccine and companion skin test move to next phase
Source: gov.uk (2025-10-21)

Step towards bovine TB cattle vaccine as phase 3 of field trials begin across England and Wales to provide additional information to guide how a vaccine can be deployed to support eradication strategies.

Field trials for a cattle vaccine and companion skin test for bovine tuberculosis (bTB) have moved to the next phase, the Animal Plant Health Agency (APHA) has announced today in a significant milestone towards disease eradication.

Vaccinating cattle against bTB, has the potential to protect individual animals from infection and create a barrier to transmission within herds and across populations. This would present a significant new tool in the fight against the disease.

Bovine TB (bTB) is one of the most difficult animal health challenges faced by the world today and in England alone it costs around £100 million every year with an estimated further £50 million cost to the wider farming industry. Over 60,000 cattle in England and Wales were slaughtered during 2023/24 to tackle the disease.

The field trials are taking place on commercial livestock farms across the Low-Risk Area in England and the Low TB Area in Wales and are due to be completed in 2026. Phase 3 will involve at least 10 farms with 750 animals participating; all the animals enrolled will receive the CattleBCG vaccine and the companion DIVA skin test.

Dr Camille Szmaragd Harrison, lead scientist for TB at the Animal Plant Health Agency, said:

The first two phases of the field trials have successfully demonstrated that the vaccine and skin test are safe to use. This third phase has been designed to provide additional information to guide how they can be deployed most effectively to support England and Wales eradication strategies.

Launching this next phase of the trials has been a collective effort, which was only made possible by the unfailing support from across the farming industry. The team and I are particularly grateful to the hundreds of farmers who expressed their interest in taking part in this trial, without them this would not have been possible.

UK Chief Veterinary Officer Christine Middlemiss said:

The UK is at the forefront of global efforts to develop effective TB cattle vaccines, and we are moving ever closer to having an operable vaccine.

That we are reaching this stage is testament to our world leading scientists in organisations like the Animal Plant Health Agency, but also to the vets and farmers that have taken part in this trial and previous trials.

If this next phase is successful, we are one step closer to a vaccine which used in conjunction with other measures will help tackle this insidious disease that impacts livestock farmers across the globe.

Chief Veterinary Officer for Wales, Richard Irvine, said:

I welcome the start of Phase 3 of the field trials on a farm in Wales. It marks another important step towards having a deployable Cattle TB Vaccine to support the eradication of TB from the national herd and to meet the target of a TB free Wales by 2041.

The first two phases of the field trials have successfully demonstrated that BCG and its companion Detect Infected among Vaccinated Animals (DIVA) skin test are safe to use. The third phase of the field trials involves gathering additional data on the companion DIVA skin test performance and explore options to optimise this.

The trial will also assess the companion DIVA skin test on a broader cohort of CattleBCG vaccinated herds, to further inform collective planning for delivery. Research studies have indicated that the vaccine and companion DIVA skin test are safe and that the test performs well, under controlled APHA facility environments.

The completion of Phase 3 will mark the end of field trials for the bTB vaccine. APHA will use data from the trials to support applications for GB Marketing Authorisations for both BCG use in cattle and the companion DIVA skin test.

It is hoped that the combination of the CattleBCG vaccine and the companion DIVA skin test will be deployable in the next few years. This could help save thousands of cattle every year that would have been culled to prevent the spread of disease.

The UK government has committed to eradicating TB by 2038 and a deployable vaccine is key to achieving that. This trial and earlier trails are a significant milestone towards that target.

More information about the bTB cattle vaccination programme can be found on the TB Hub (https://tbhub.co.uk/resources/frequently-asked-questions/development-of-a-deployable-tuberculosis-vaccine-for-cattle/).

ENDS

Notes to editors:
- Since July 2021, APHA has completed Phase 1 which focused on the safety and performance of the companion skin test in unvaccinated animals and Phase 2 that gathered data on the safety of the CattleBCG vaccine and the safety and performance of the companion DIVA skin test in vaccinated cattle. Approximately 1100 cattle from 13 herds in the low-risk area in England have taken part in these two phases.
- The Veterinary Medicines Directorate is responsible for authorising veterinary medicines in the UK. The World Organisation for Animal Health is responsible for setting international standards for animal health and trade.