APHA announced in October 2025 that field trials for the bTB cattle vaccination and new companion skin test developed to be able to Detect Infected among Vaccinated Animals (DIVA) have moved to the next phase.
Since July 2021, APHA has completed Phase 1, which focused on the safety and specificity 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 specificity of the companion DIVA skin test in vaccinated cattle. Approximately 1,100 cattle from 13 herds in the low-risk area in England have taken part in these two phases.
Phases 1 and 2 of the trial have confirmed strong safety profiles for both the vaccine and the DIVA test reagent, reinforcing their potential for field use. However, Phase 2 identified two false positives in animals tested with the DIVA skin test. To ensure the test meets the high diagnostic standards required, further data on the specificity of the test is needed. Phase 3 is now underway to generate additional data on the DIVA skin test’s performance in a broader cohort of BCG-vaccinated animals.
The third phase of the trial will include at least 750 animals from a minimum 10 TB-free farms located in England’s Low-Risk Area (LRA) and Wales’ Low TB Area (LTBA). The goal of this phase is to optimise and refine the diagnostic accuracy of the DIVA skin test and ensure its reliability for future deployment in TB control programmes.
The data gathered in Phase 3 will play a critical role in progressing the applications for GB Marketing Authorisation (MA) for both BCG use in cattle and for the companion DIVA skin test.
If successful, Phase 3 will mark a major step toward making a deployable TB vaccine available to GB vets and farmers. Used in conjunction with the existing TB control measures, the vaccine will enhance our ability to manage this insidious disease which impacts cattle farmers both in the UK and abroad.
Further information is available on the TB Hub.
