Why Badger Vaccination won’t save the badger

Exploring the difference between fantasy and fact and if badger vaccination really is the golden egg we have all been waiting for.

Badger vaccination has been sold as a panacea to saving the lives of badgers from the ineffective badger cull. Indeed, the recent catchy slogan from the government for their ‘badger vaccinator field force’, would imply that vaccination can put a ‘force field’ around badgers' lives. Are they suggesting that after 11 years of government-sanctioned culling, this government field force will be the badger army that badgers have been waiting for to save them? 

But Star Trek-shaped heroes out to save badgers aside, will vaccination with the Bacille Calmette-Guérin (BCG) vaccine save the badger? And if so, from what? Here we show the difference between fantasy and fact and explore if badger vaccination really is the golden egg we have all been waiting for or if the issue is far more complex than a government re-brand would imply.

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For 11 years the government has mass slaughtered badgers on an unprecedented scale.  Over 230,000 badgers, and counting, have been shot in an ineffective, and unethical attempt to curb Bovine Tuberculosis (bTB) rates in farmed cattle. If you are new to our work, let's fill you in quickly: it hasn’t worked [1]. 

Studies previously showing the potential effects of badger culling on bTB rates in cattle have failed to distinguish the impacts of culling from other measures in place, including improved testing and biosecurity in high risk areas [2, 3]. Infection rates in cows are as high now as they have ever been because bTB is overwhelmingly spread cow-to-cow [4]. Given the inaccuracy of the tests used to detect bTB in cattle, infection rates could actually be even higher than in previous decades.

Unfortunately, badger vaccination not only keeps the narrative of blame misplaced on the badger, it will never save the badger as it is an impractical and unrealistic solution to slowing bTB spread in an entirely different species — cattle.  As we will see in this article, badger vaccination will collapse when applied at scale as it is hugely expensive, impractical to roll out on a large scale, needs repeating regularly — ideally with a yearly booster [5], and — just like killing badgers — lacks evidence for its effectiveness to reduce disease-spread to cattle. 

But, let’s not let facts get in the way of a well-sloganed ‘plan’.  

To top it off, vaccinated badgers are not immune from being culled, and for years vaccinated badgers have gone on to be culled, thus vaccination offers them no protection from their main threat —being shot. Consequently, this raises serious concerns about wasting time and resources on badger vaccination programmes that ultimately do not safeguard these animals.

What is the BadgerBCG vaccination, and does it work?

Badger vaccination in this context refers to the Bacille Calmette-Guérin (BCG) vaccine and is used to vaccinate badgers against M.bovis, the organism that causes bovine Tuberculosis in a variety of hosts; cows, dogs, cats, humans, badgers, deer, and even earthworms have been shown to carry the organism [5, 6]. Badgers are a protected species, and so their capture, marking, and vaccination are only permissible under licence by trained individuals. These licences are issued by Defra and Natural England [7].

The first challenge of administering the vaccine to a wild badger is catching it. Badgers are baited with peanuts for up to two weeks to get them used to feeding in a certain area and used to the cage traps. However, in areas where culling has happened for years, cage trapping has rendered much of the remaining population rightly wary of entering the cages. If and when a badger is finally caught, it is then given an intramuscular injection of BCG.  You can’t just walk up to a badger, put it in a crush cage, and stab it with a needle as you can a farmed cow that is accustomed to veterinary treatments. Some badgers might be tagged or marked to show they have been vaccinated. If not, or if the mark is not easily visible, the same badger may get a repeat vaccination in one season. Each cage trap must then be removed, disinfected, and reset between vaccinations.

Significant investment (over £16 million and counting [5]) has been put into the research and development of the injectable vaccine, which has been shown to be effective at reducing both the severity of bTB spread, and the amount of transmission between individuals of the same species [8].  In one study, it also showed a protective effect in unvaccinated cubs [9].  An oral vaccine was trialled, but the field trials rendered it completely impractical for real-world applications [10, 11].

The results were promising for protecting badgers against bTB and reducing the spread of it amongst their own species. Like most vaccinations, however, the protection from the vaccine decreases over time [12].  Furthermore, from the rare studies that have bothered to test badgers for bTB, incidence amongst populations is low (1-9% in most cases, with some studies showing up to 15% [5, 13, 14]). As a result, the BCG vaccine is rarely necessary to protect badgers from bTB.

The Welsh “All Wales Badger Found Dead Survey” is a national study that provides a more comprehensive assessment of bTB in badgers compared to studies conducted in England. Since the survey began, 92.1% of badgers found dead in Wales have tested free from bTB [15].  Of those identified as having bTB-like lesions, it is unclear how many were actually infectious. 

As a result of these studies in Wales, badgers are not considered a zoonotic risk to other animals or humans due to the low levels of bTB in the badger population (this is part of the Animal Health and Welfare Framework Implementation Plan 2022-2024 for Wales).  Badgers are not routinely tested for bTB in England, but if they were, the results would likely be similar.

Badgers have an unusual capacity to carry a high bacterial load of this cattle disease, without themselves being sick or infectious [5].  Bovine TB does not, therefore, exert a direct strong selective pressure on badger populations. Being able to tolerate high densities of various environmental mycobacteria — including M. bovis, which causes bTB — found in the soil where they live and eat, may be an evolutionary tactic of badgers developed over 250,000 years [5]. 

Whilst many badgers can carry this very high load for years without becoming morbid or infectious [5], a small number of those may become sick from TB. It is unclear, however, in what context this happens, and how many individuals actually die from the disease itself, or from a secondary infection resulting from compromised immunity. For a badger to become sick from TB, it is likely that it was already under stress or suffered other health issues, making it more susceptible to the latent infection. 

The vital question should therefore be, what are we humans doing to stress badgers out? Besides mass shooting them, of course. Do badgers have enough food? Enough space to forage and build setts without facing intense competition for resources? Are they protected from disturbance and safe from persecution?  Just as overcrowded and stressed livestock are more susceptible to disease, disruption and disturbance to badgers caused by anthropogenic pressures can cause a bTB infection in a badger to go from harmlessly latent to potentially infectious — but happy badgers are much more likely to remain healthy. 

Vaccination might make us feel good as human beings: it might protect individual badgers from cattle-borne bTB, but like culling, it will have no meaningful effect on bTB in cattle.

Vaccination, in this sense, seems to be a feel-good band-aid to dealing with the root cause.

Cattle infection and BadgerBCG

There is a current lack of evidence on whether vaccinating badgers has any impact on reducing the spread of bTB amongst cattle. Logically, if culling badgers over the last 11 years has had no meaningful effect on bTB in cattle [16], then vaccinating badgers is unlikely to have a greater effect. 

Farmers seemingly share this doubt where research has shown that farmers perceive badger vaccination to be ineffective at reducing bTB incidence in cattle [17, 18]. As we know, at least 94% of bTB in cattle is spread cow-cow [19], with the remaining 6% being transmitted via a variety of diverse pathways, including poor biosecurity on farms, slurry, and other domestic and wild animals. This is especially true if you are in an enclosed space, and already happen to be pretty stressed from living in overcrowded, dirty, dark housing. 

Bovine TB spreads much like human TB: through close contact with an infected individual. As badgers aren’t exactly getting nose to nose with cows very often, transmission between them likely occurs indirectly, such as through exposure to contaminated faeces. And yet, the government wastes millions of pounds on culling native animals, on the very small chance that a cow could contract bTB from unlikely, and very avoidable, indirect contact with an infectious badger. 

As badgers only account for, at most, a very small proportion of bTB transmission to cattle and, in fact, are 800 times more likely to have caught it from the cattle in the first place [20], efforts to reduce bTB through vaccinating badgers alone are unlikely to be effective without an equal or greater focus on improving farm biosecurity, biocontainment, and reducing cattle-cattle transmission rates.

The East Sussex Vaccination Trial: Cost vs Sense

The government’s major badger vaccination trial, running since 2021, is a great example of more money than sense. Costing the tax-payer £2.27 million [21], the industry-delivered VESBA trial in East Sussex has managed to vaccinate a grand total of 1,436 badgers across 250 km2 in the four years it has currently been running [22]. To put this in context, the government has killed at least 86,884 badgers as part of the cull in these same four years at the cost of over £24 million. It is unclear how much was spent on cattle-based measures to prevent bTB prevalence in this period. 

Based on this scale, the government would need 1,351 years (perhaps their field force team is counting in light years) to vaccinate every single badger just once in England, at the cost to the tax-payer of £766,678,273 (this is based on a likely overestimate of 485,000 badgers in England from the pre-cull 2013 national badger survey [23]. And this is only the beginning, as effective vaccination would ideally need to be repeated each year to maintain long-term immunity. 

Even if we try to be more generous, and look at the national figures for badger vaccination across wildlife groups and APHA-delivered programmes, we can see large-scale badger vaccination is still not practical. In 2023, 4,604 badgers were vaccinated by both APHA staff and other trained badger vaccinators, typically volunteers and wildlife group staff and volunteers. This is up from the 2,434 badgers vaccinated in 2022 [24]. From these figures, it is unclear if any of these badgers vaccinated were receiving repeat shots — either from mistaken identity in the first year or from a previous year of vaccination. 

Even if we assume that these are all unique badgers receiving their first and only shot of the vaccination, at this scale, this would still take 105 years to vaccinate 485,000 badgers in England just once. Even if we help the government a little bit more, and say, ‘Well, maybe there is only half the population of badgers left now because of the government cull’ and say there are 242,500 badgers in England, this would still take 53 years to vaccinate every single badger just once. 

Ok, this all makes for grim reading. Let’s help them out a bit more. Models have suggested that annual badger BCG vaccination of 70% of badgers could eradicate bTB from their populations in 20-30 years, depending, of course, on how many times they get reinfected by cattle [5, 25].  

If we calculate then that we don’t need to vaccinate every single badger to protect against TB, and that two-thirds of the population is enough [5], at the lowest scale of 242,500 badgers left, this would still take 35 years to vaccinate enough badgers to reduce TB spread amongst the badger population. 

This lengthy vaccination plan is based on the reduced effectiveness of just one dose of the vaccine, when repeat doses are shown to be more effective at reducing disease spread and severity in badgers.  Remember, the true measure of ‘effectiveness’ for the government here is actually that it will reduce TB in a completely different species, the cow, when cow-cow transmission is proven to be the biggest pathway by far. Bonkers, we know.

Oh, and did we mention that the average badger only lives to be around 5 years old?

Clearly, badger vaccination at scale is completely impractical and unrealistic, so why are the government continuing to pursue it? 

The Anti-Badger Narrative Continues

The Labour government admitted in their manifesto pledge that the cull is ‘ineffective’, but is now back-pedalling in its commitment to this.  

Their tactic? Keep culling for at least a couple more years and, at the same time, bring in wide-scale badger vaccination while culling is kept on the table. This approach keeps the narrative firmly on the badger, without drawing attention to the ineffectiveness of the main drivers of bTB — inaccurate cattle testing and unregulated cattle movements — and keeps some of the farmers, conservationists, and animal welfare groups happy. Some more badgers die for a while (based on current projections, this is expected to be at least another 50,000 individuals), but a promise that it will be stopped eventually for a more humane approach to vaccination is dangled like a golden carrot. Win-win for all, right? Wrong.

The government has also announced that they will be carrying out a badger vaccination study to analyse the effect of badger vaccination on the incidence of TB in cattle.  Minister of State for Defra, Daniel Zeichner, has said the reason for this is “to encourage farmers to take part and provide greater confidence that doing so will have a positive effect on their cattle” [26].  This pre-emptive language implies that they have already decided on the results of the study.  Given that this is not a clinical trial, and therefore the results of badger vaccination, much like the cull, can’t be differentiated from the cattle measures also being implemented, we can say with some certainty that the government will get the results they want.  

To complicate matters further, vaccinating badgers makes testing more challenging. The vaccine can trigger an immune response that can affect the specificity of tests, making it harder to tell if the animal has been exposed to the disease or has reacted to the vaccine itself [8, 27, 28].  This can lead to inflated bTB rates in badgers, making the disease appear more widespread in populations than it actually is.

Finally, some believe that vaccination will prove badgers are not the source of bTB in cattle, and farmers will stop wanting to cull them. However, in a 2023 Badger Trust survey, 87.3% of farmers said badgers should be culled regardless of bTB. 

The anti-badger narrative continues.

Badger Trust and BadgerBCG Vaccination

And so, as the leading voice for Badgers in England and Wales, Badger Trust’s position on badgerBCG vaccination, is that it is a costly and ineffective distraction to dealing with the root cause of bTB in cattle, political ineffectiveness. 

Badger Trust does award vaccination grants to locally based, not-for-profit, voluntary and charitable groups and organisations, working for the protection of badgers. These projects are supported with grants in order to protect badgers and help local groups to try and offer an alternative in areas where culling is being considered, and to ultimately save badgers' lives.

Badger Trust actively wants healthy badgers, and whilst there is, of course, merit to protecting our native badgers from this cattle disease, we would much rather focus efforts and limited resources on the much more effective root of the problem, the cow.   

Improving cattle measures — including better testing, movement controls, herd health and welfare monitoring, and strict biosecurity — remains the only way to keep our wild badger population, and those of deer and other animals, from contracting bTB in the first place.

Tackling bTB in cattle is not a quick fix, especially since it has become so widespread. Decades of gassing and shooting badgers haven’t reduced bTB in cattle. Even cattle measures will take time to have an effect, even longer when the policies in place aren’t strong enough to detect all the infected cattle, as is currently the case. So yes, tackling bTB in cattle is a case of playing the long game. But, it’s an even longer, endless game, if you spend decades vaccinating badgers, and not the cows. 

After decades of badger persecution from the government, can we really trust them in this new fantasy story to be the ‘field force’ for badgers they are promising? You decide.

References

[1] Torgerson, P.R., Hartnack, S., Rasmussen, P., Lewis, F., and Langton, T.E., 2024. Absence of effects of widespread badger culling on tuberculosis in cattle. Scientific Reports, 14(1), p.16326.

[2] Birch, C.P., Bakrania, M., Prosser, A., Brown, D., Withenshaw, S.M., and Downs, S.H., 2024. Difference in differences analysis evaluates the effects of the badger control policy on bovine tuberculosis in England. Scientific Reports, 14(1), p.4849.

[3] Downs, S.H., Prosser, A., Ashton, A., Ashfield, S., Brunton, L.A., Brouwer, A., Upton, P., Robertson, A., Donnelly, C.A., and Parry, J.E., 2019. Assessing effects from four years of industry-led badger culling in England on the incidence of bovine tuberculosis in cattle, 2013–2017. Scientific Reports, 9(1), 1-14.

[4] McGill, I., and Jones, M., 2019. Cattle infectivity is driving the bTB epidemic. Veterinary Record, 185(22), 699-700.

[5] Macdonald, D., and Newman, C., 2022. The Badgers of Wytham Woods: A Model for Behaviour, Ecology, and Evolution. Oxford University Press, New York, p. 366.

[6] Snider, W.R., Cohen, D., Reif, J.S., Stein, S.C., and Prier, J.E., 1971. Tuberculosis in Canine and Feline Populations: Study of High-Risk Populations in Pennsylvania, 1966–1968. American Review of Respiratory Disease, 104(6), 866-876.

[7] Summary of Badger Vaccination in 2023. GOV.UK, 2024, https://www.gov.uk/government/publications/bovine-tb-summary-of-badger-control-monitoring-during-2023/summary-of-badger-vaccination-in-2023. [Date Accessed: 04.11.24].

[8] Chambers, M.A., Rogers, F., Delahay, R.J., Lesellier, S., Ashford, R., Dalley, D., and Hewinson, R.G., 2010. Bacillus Calmette-Guérin vaccination reduces the severity and progression of tuberculosis in badgers. Proceedings of the Royal Society B: Biological Sciences, 278(1713), 1913-1920.

[9] Carter, S.P., Chambers, M.A., Rushton, S.P., Shirley, M.D., Schuchert, P., Pietravalle, S., Murray, A., Rogers, F., Gettinby, G., Smith, G.C., and Delahay, R.J., 2012. BCG vaccination reduces risk of tuberculosis infection in vaccinated badgers and unvaccinated badger cubs. PLOS ONE, 7(12), e49833.

[10] Aznar, I., Frankena, K., More, S.J., O’Keeffe, J., McGrath, G., and De Jong, M.C.M., 2018. Quantification of Mycobacterium bovis transmission in a badger vaccine field trial. Preventive Veterinary Medicine, 149, 29-37.

[11] Chambers, M.A., Aldwell, F., Williams, G.A., Palmer, S., Gowtage, S., Ashford, R., Dalley, D.J., Davé, D., Weyer, U., Salguero, F.J., and Nunez, A., 2017. The effect of oral vaccination with Mycobacterium bovis BCG on the development of tuberculosis in captive European badgers (Meles meles). Frontiers in Cellular and Infection Microbiology, 7, 6.

[12] Sterne, J.A.C., Rodrigues, L.C. and Guedes, I.N., 1998. Does the efficacy of BCG decline with time since vaccination? The International Journal of Tuberculosis and Lung Disease, 2(3), pp.200-207.

[13] Bennet., M. 2018. A study into the prevalence of bTB in found-dead badgers in the northern ‘Edge Area’ of England. School of Veterinary Science and Medicine, University of Nottingham.

[14] Palgrave, C. and Chambers, M., 2018. A study into the prevalence of bTB in found-dead badgers in the southern ‘Edge Area’ counties of England. School of Veterinary Medicine, University of Surrey.

[15] Llywodraeth Cymru Welsh Government, 2021. A Refreshed TB Eradication Programme. Welsh Government Consultation Document. pdf. Available from: https://www.gov.wales/sites/default/files/consultations/2021-11/refreshed-tb-consultation-document.pdf [Date Accessed: 26.06.2023].

[16] Langton, T.E., Jones, M.W. and McGill, I., 2022. Analysis of the impact of badger culling on bovine tuberculosis in cattle in the high-risk area of England, 2009–2020. Veterinary Record, 190(6): e1384.

[17] Benton, C.H., Phoenix, J., Smith, F.A., Robertson, A., McDonald, R.A., Wilson, G. and Delahay, R.J., 2020. Badger vaccination in England: Progress, operational effectiveness, and participant motivations. People and Nature, 2(3): 761-775.

[18] Chivers, C.A., Maye, D., Lenormand, T., Enticott, G. and Tomlinson, S., 2022. Exploring farmer attitudes towards the vaccination of badgers against bovine tuberculosis. Technical Report, University of Gloucestershire. Available from: https://sciencesearch.defra.gov.uk/ProjectDetails?ProjectId=20949 [Date Accessed: 04.11.24]

[19] Donnelly, C.A. and Nouvellet, P., 2013. The contribution of badgers to confirmed tuberculosis in cattle in high-incidence areas in England. PLOS Currents, 5.

[20] Akhmetova, A., Guerrero, J., McAdam, P., Salvador, L., Crispell, J., Lavery, J., Presho, E., Kao, R., Biek, R., Menzies, F., Trimble, N., Harwood, R., Pepler, P., Oravcova, K., Graham, J., Skuce, R., du Plessis, L., Thompson, S., Wright, L., Byrne, A. and Allen, A. 2023. Genomic epidemiology of Mycobacterium bovis infection in sympatric badger and cattle populations in Northern Ireland. Microbial Genomics, 9(5): mgen001023.

[21] Next Phase of Bovine TB Eradication Strategy Confirmed. DEFRA Media, 28 May 2021. https://deframedia.blog.gov.uk/2021/05/28/next-phase-of-btb-eradication-strategy-confirmed [Date Accessed: 04.11.24]

[22] VESBA Newsletter May 2024. Veterinary Ecological and Biological Society of the UK, 2024. https://www.vesba.org.uk/wp-content/uploads/2024/06/VESBA-Newsletter-May-2024.pdf. [Date Accessed: 04.11.24]

[23] Judge, J., Wilson, G.J., Macarthur, R., McDonald, R.A. and Delahay, R.J., 2017. Abundance of badgers (Meles meles) in England and Wales. Scientific Reports, 7(1), p.276.

[24] Summary of Badger Vaccination in 2022. GOV.UK, 2023, https://www.gov.uk/government/publications/bovine-tb-summary-of-badger-control-monitoring-during-2022/summary-of-badger-vaccination-in-2022. [Date Accessed: 04.11.24]

[25] Wilkinson, D., Smith, G.C., Delahay, R.J., and Cheeseman, C.L., 2004. A model of bovine tuberculosis in the badger Meles meles: An evaluation of different vaccination strategies. Journal of Applied Ecology, 41(3), 492-501.

[26] Badgers: Disease Control. TheyWorkForYou, 10 Sept. 2024, https://www.theyworkforyou.com/wrans/?id=2024-09-02.3800.h&s=badger. [Date Accessed: 04.11.24]

[27] Animal & Plant Health Agency. (2023). Bovine TB: Badger trapping and testing on chronic TB breakdown farms, 2022. Welsh Government. https://www.gov.wales/sites/default/files/publications/2023-09/bovine-tb-badger-trapping-and-testing-chronic-tb-breakdown-farms-2022.pdf [Date Accessed: 04.11.24]

[28] Lesellier, S., Palmer, S., Gowtage-Sequiera, S., Ashford, R., Dalley, D., et al., 2011. Protection of Eurasian badgers (Meles meles) from tuberculosis after intramuscular vaccination with different doses of BCG. Vaccine, 29: 3782–3790.