The Sussex Wildlife Trust believes that in the short-term, badger vaccination has the potential to help reduce bTB in cattle without the negative impacts related to badger culling.
The problem with culling
The Government's focus on culling badgers is more a distraction than a solution to tackling this disease. Scientists, who have studied the impacts of a badger cull in England on bovine TB for many years, have stressed it will make only a limited contribution to tackling bTB (1).
Large-scale badger culling trials showed an initial worsening of the disease due to the 'perturbation effect'. Over the longer term, culling may result in a positive impact of a 12-16% reduction of bTB in cattle, but this still leaves at least 84% of the problem. Lord Krebs, who designed the Randomised Badger Culling Trial, concluded that "culling is not a viable policy option" (2).
What is the perturbation effect?
During the Randomised Badger Culling Trial (RBCT), culling consistently increased the prevalence of bTB in badgers.
Badgers typically live in social groups of four to seven animals with defined territorial boundaries. In a stable badger population, there is limited movement from one area to another. As a result, a badger sett harbouring high levels of bTB infection would tend to remain relatively isolated. Removing badgers from cull areas opens up the territory, allowing badgers to come in from the surrounding areas. Badger movements around and beyond the infected area therefore increase, and immigrant badgers are at risk of infection from abandoned setts and un-culled infected animals. Badger to badger transmission increases, along with the likelihood of badger to cattle transmission. Because the population is still lower than the carrying capacity of the total area, badgers move around much more than they did before the cull, and this movement distributes the original infection over a wider area. This is known as the 'perturbation effect'.
Vaccination is a viable option
Since 1998, the Government has invested £30 million in developing bTB vaccines for cattle and badgers. The current status of vaccine development is:
- An injectable vaccine called Badger BCG has been available since 2010
- An oral badger vaccine is being developed - but it needs to be tested before potential submission to regulatory bodies, and is not yet in use
- A cattle vaccine is being developed but requires regulatory approval and changes to EU legislation to permit its use
The Wildlife Trusts believe that cattle measures should be at the centre of efforts to tackle bTB, alongside a strategic programme of badger vaccination. In the longer term, cattle vaccination will have a vital role to play but it is not yet available.
A vaccine for badgers is available now and has the potential to help reduce bTB in cattle without the negative impacts of perturbation arising from a badger cull.
Vaccination is effective
Vaccinating badgers can significantly reduce the extent of bTB and the potential for transmission to cattle without the disruption of a cull. In a veterinary field study, vaccinating wild badgers resulted in a 74% reduction in the incidence of badgers testing positive to the antibody blood test for TB (3).
Vaccinating badgers can significantly reduce the number of cubs testing positive for bTB. The same veterinary field study found that when more than a third of badgers in a social group had been vaccinated, the risk to un-vaccinated cubs was reduced by 79% (4).
In comparison, culling trials have shown that shooting 70% of a badger population could reduce bTB cases in cattle by 12–23% over nine years, but may increase cases of bTB on the outskirts of the cull zone.
Ultimately, however, we believe that a cattle vaccine is the sustainable long term solution and we will continue to lobby for Government to make a cattle vaccine a reality.
Vaccination is underway
Badger vaccination forms part of the Government's Strategy for achieving Officially Bovine Tuberculosis Free status for England and the Government's Badger Edge Vaccination Scheme (BEVS 2) provides funding towards the cost of vaccinating badgers in the Edge Area of England. The Edge Area is the buffer zone between the High and Low Risk Areas and currently includes all of Berkshire, Buckinghamshire, Cheshire, Derbyshire, East Sussex, Hampshire, Leicestershire, Northamptonshire, Nottinghamshire, Oxfordshire and Warwickshire.
A number of Wildlife Trusts are running badger vaccination programmes across England and in Wales - find out more.
1. The Duration of the Effects of Repeated Widespread Badger Culling on Cattle Tuberculosis Following the Cessation of Culling. Jenkins et el (2010)
2. Bovine TB: The Scientific Evidence. Independent Scientific Group on Cattle TB (2007)
3. Bacillus Calmette-Guérin vaccination reduces the severity and progression of tuberculosis in badgers. Chambers et el (2011)
4. BCG Vaccination Reduces Risk of Tuberculosis Infection in Vaccinated Badgers and Unvaccinated Badger Cubs. Carter et el(2012)