New evidence from a four-year field study has shown that vaccination reduces the risk of tuberculosis infection in unvaccinated badger cubs when they are in vaccinated groups.
The research provides the strongest evidence to date that unvaccinated badger cubs can be indirectly protected from bovine TB infection when some of the badgers in their social group are vaccinated. Researchers have shown that the risk of non-vaccinated cubs testing positive was reduced by almost 80% when more than a third of badgers in their group had been vaccinated.
However, with pilot culls of badgers in two South West bovine TB hotspot areas scheduled to take place next summer, farmers say the research does not have any relevance in badger-to-cattle infection.
The data comes from a controlled clinical field trial of badger vaccination, conducted by the Animal Health and Veterinary Laboratories Agency (AHVLA) and the Food and Environment Research Agency (Fera), in an area in Gloucestershire, where TB is highly prevalent in the badger population. The latest analyses were conducted by a team of scientists at Fera, AHVLA and the Universities of Newcastle and Strathclyde.
Professor Robbie McDonald, author of the paper and now at the University of Exeter, 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."
Andrew Butler, acting regional director of the National Farmers' Union in the South West, commented: "From the summary this research is only looking at the effectiveness of vaccination of badgers.
"Crucially what this study has not done, or any other study into vaccination of badgers to date, is look at the impact of badger vaccination on TB levels in the cattle herd and its cost effectiveness.
"This is vital – and until the industry sees some research that shows significant reductions in the disease in cattle at a reasonable cost, vaccination of badgers will not be a solution to controlling TB in our cattle."