The need for large-scale badger culling across England to control bovineTB seems to be reducing as new evidence from government-funded vaccine trials show that badger vaccines can be even more effective than previously thought.
The vaccine trials were carried out by the Department of Environment and Rural Affairs (DEFRA) agencies the Animal Health and Veterinary Laboratories Agency (AHVLA) and the Food and Environment Research Agency (Fera). The trial covered a four-year period and was undertaken in Gloucestershire.
Also involved in the study were the universities at Newcastle and Strathclyde who were involved in the analysis of the figures.
The vaccine trial showed that even unvaccinated badger cubs were protected by the vaccine as long as a third of the setts badgers were given the BCG vaccine. The chances of an unvaccinated badger cub getting TB was 80% lower in a sett which had vaccinated badgers than in a sett without.
This study indicates that vaccination of badgers above ground can indirectly protect unvaccinated cubs before they emerge from the sett.
One of the biggest concerns over whether vaccination could be a viable alternative to culling was that many badger cubs would be infected with the disease before they even left the sett for the first time and certainly before they could be trapped and vaccinated.
The new study shows that this issue may not be such a concern.
Dr Steve Carter of Fera and lead author of the latest research said: “One concern about the effectiveness of badger vaccination is that new-born cubs might acquire TB before they first emerge above ground. As the vaccine is not expected to benefit infected individuals it has been suggested that by the time cubs emerge and are available for vaccination they might have already been exposed to TB. Therefore, vaccination for them may be too late. This study indicates that vaccination of badgers above ground can indirectly protect unvaccinated cubs before they emerge from the sett”.
Professor Robbie McDonald, an author of the paper and now at the University of Exeter’s Environment and Sustainability Institute, said: “This striking result in cubs shows a protective effect at the social group level and is important evidence that vaccination not only has a direct benefit to vaccinated badgers, but can also reduce the infectivity of TB within a badger social group that has been vaccinated.”
But he cautioned: “Although this is an encouraging development, the costs and benefits of vaccinating badgers for controlling disease in cattle are not yet well understood”.
“This means that it is a hard choice for farmers to make without further information and trials of how it would work in practice. The current Badger Vaccine Deployment Project in Gloucestershire and experience in the Welsh Government’s badger vaccine project will help deliver this experience and knowledge.”
University of Exeter: Vaccination reduces the risk of unvaccinated badger cubs testing TB positive.