Why vaccinate badgers?
Laboratory studies and research on wild badgers in the field have shown that injecting badgers with BCG significantly reduces the progression and severity of TB and the excretion of TB bacteria. Furthermore, unlike culling, vaccination does not disrupt badger social groups and therefore doesn’t risk increased TB infection in both badgers and cattle as a result of perturbation (Defra 2011, Paras 3.6 & 3.11)
Badger vaccination thus has the potential to reduce the risk of badgers getting TB from each other, from cattle and from other sources of TB. This in turn reduces the chances of TB spreading within the badger population and thus the likelihood of infected badgers transmitting TB to cattle.
The ultimate goal of a badger vaccination campaign would be to achieve ‘herd immunity’ in the badger population – a situation in which further transmission of TB from badger to badger has become unlikely because a large enough proportion of the total population has become immune to the disease either through vaccination and/or by having natural or acquired resistance to the disease e.g. by getting it and surviving.
Herd immunity is a well-documented effect in both humans and animals. As more and more individuals in the population acquire resistance, the disease has less chance of spreading within the community. This in turn is likely to greatly reduce any potential risks of TB transmission from badgers to cattle (Defra 2011, Para 3.8-3.10).
Research published in December 2012 showed that vaccination not only significantly reduced the direct risk of an individual badger developing TB, but that it also provided some immunity indirectly to unvaccinated badger cubs hidden away underground. Furthermore, these results were achieved when more than a third of badgers were vaccinated – i.e. not every individual badger had to be vaccinated.
This research provides direct experimental evidence that if you vaccinate a sufficient proportion of badgers, the total population is likely to become immune to TB over a period of years.
You can read a summary of this paper under Badgergate’s Technical Papers or download the full paper here: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0049833
Existing badger vaccination efforts
Since March 2010, an injectable badger TB vaccine (officially known as BadgerBCG) has been licenced for use in the UK (Defra 2011, Para 3.7).
A number of charities that pledged not to allow badger culling to take place on their land have already implemented small-scale badger vaccination trials, some from as early as 2010. These include the RSPB and at least twelve Wildlife Trusts, notably the Gloucestershire Wildlife Trust. The National Trust is also running its own badger vaccination programme on one of its estates in Devon, while the Badger Trust supports badger vaccination through its affiliated local badger groups, such as the Somerset Badger Group, which is vaccinating badgers on land owned by farmers in Somerset.
On a larger scale, the Welsh Government scrapped plans for a badger cull in March 2012 in favour of a widespread vaccination programme along with other bTB control measures. The UK Coalition Government is also supporting a large badger vaccination trial in Gloucestershire.
Challenges associated with badger vaccination
One of the main criticisms of badger vaccination, especially by Government and the NFU, is that it is just too expensive. Other criticisms include:
- the logistical challenges of catching and vaccinating badgers;
- the fact that the vaccine is not 100% effective in preventing TB in badgers;
- the fact that the vaccine will not cure badgers that are already infected; and
- that we don’t know what proportion of TB incidence in cattle could be reduced by vaccinating badgers against TB.
An oral vaccine against TB for use in badgers has been under development for some time. This would be much more cost-effective to administer as it would not require badgers to be trapped and vaccinated by injection. But in the absence of a licenced oral vaccine for badgers, cost remains the single biggest obstacle to scaling up existing badger vaccination efforts.
In this section, Badgergate will examine the pros and cons of badger vaccination more systematically, with a focus on the costs of vaccination and the options for reducing these.
We’re still working on badger vaccination costs and hope to upload our first analysis of these soon. But in the meantime, we’ve included a summary of who’s currently vaccinating badgers along with a summary of the key features of the Welsh Badger Vaccination Programme (BVP). We hope to include summaries of other on-going vaccination programmes in due course.
We also plan to review the evidence submitted to the EFRA Select Committee during the course of its inquiry into the vaccination of badgers and cattle in relation to bovine TB.
References: Defra 2011. The Government’s Policy on Bovine TB and badger control in England. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/69463/pb13691-bovinetb-policy-statement.pdf