Most recent
 Badger cull thoroughness
Added or updated 24 hours ago
PDF icon RFI 4007 Response to Customer 081117
Added or updated 2 weeks ago
PDF icon untitled
Added or updated 2 weeks ago
PDF icon Quantification of Mycobacterium bovis transmission in a badger vaccine field trial
Added or updated 3 weeks ago
 Is specificity of the skin test over-estimated?
Added or updated 4 weeks ago
PDF icon Badgers and TB in Cattle: the view of a dairy farmer. Land-Care. 27 February 2003.
Added or updated 4 weeks ago
 Impact of badgers on bovine TB in different areas of GB
Added or updated one month ago
 Gassing of badger setts
Added or updated 2 months ago
 Bovine TB in GB. Latest SAM data, maps and older VETNET data.
Added or updated 2 months ago
PDF icon Bovine TB strategy launched to make England disease free within 25 years. DEFRA. Published 4th July 2013.
Added or updated 2 months ago
 An example of how badger culling in the UK is being cast in a negative light
Added or updated 2 months ago
 Randomised Badger Culling Trial: Was there an overall TB increase in the adjoining lands?
Added or updated 2 months ago
PDF icon Killing thousands more badgers won't eradicate TB in cattle. R Woodroffe. New Scientist. COMMENT. 14 September 2017.
Added or updated 2 months ago
Added or updated 3 months ago
 Accuracy of the TB test for cattle
Added or updated 4 months ago
 Bovine TB in the UK, England, Ireland, Wales and New Zealand
Added or updated 4 months ago
PDF icon New light on the secret life of badgers. University of Oxford. 17 July 2017.
Added or updated 5 months ago
 Level of spend on culling needed to reduce TB
Added or updated 5 months ago
 Bovine TB in New Zealand
Added or updated 5 months ago
PDF icon Freedom of Information Response. APHA. ATIC1096. 9 June 2017
Added or updated 6 months ago

Impact of the BCG vaccine on the prevalence of TB in badgers

The largest and most thorough trial of badger vaccination ever undertaken in the UK was conducted in Gloucestershire between 2006 and 2009. The report was peer reviewed and one of the authors was the APHA Chief Scientist Glyn Hewinson.

In the vaccination trial about 200 badgers were vaccinated each year over 4 years over an area of about 55 sq km. Badgers were vaccinated on a group by group basis instead of over one wide area. This means that the mixing between vaccinated and unvaccinated badgers would have been greater in the trial than if the treatment had been implemented in a wide-area roll out. As such the challenge to the vaccine was greater in the trial than in a typical rollout.

What impact did the BCG vaccine have on the prevalence of TB in badgers after 4 years? This is an important question because it is hoped that vaccination will build herd immunity in treated badger populations over the course of time.

The scientists failed to detect a significant herd effect in terms of prevalence in the 200 badgers vaccinated at the end of the 4 years. In fact when these badgers were triple tested in 2009, the prevalence level in the 100 unvaccinated controls was 36.8% and in the 200 vaccinated treated badgers was 33.8%. Another words the prevalence level of TB in badgers had dropped by (36.8 - 33.8) / 36.8% = 8% over the course of 4 years2. When 95% confidence levels are considered this effect is statistically insignificant.

So where is this 79% reduction in risk in unvaccinated cubs coming from?

This is the amount by which TB incidence reduced in unvaccinated cubs. It is thought that TB in these cubs dropped because they were subjected to less infection largely on account of the vaccinated badgers they came into contact with.

Ultimately however what counts is the amount by which TB levels (i.e. prevalence) drops. Incidence is a measure of the number of events which gives rise to TB level. If the incidence drops but does not lead to a drop in TB level, there would have been no benefit.

Although the impact of the treatment on incidence is encouraging, the ultimate test is if TB levels drop. If the treatment is causing badgers to live longer and hence spread their reduced infection during the course of a longer lifetime, it is possible that the treatment had no impact on the overall extent to which they were exposing other badgers (and cattle) to their infection.

To see the report, please refer to,

BCG Vaccination Reduces Risk of Tuberculosis Infection in Vaccinated Badgers and Unvaccinated Badger Cubs


  1. Bovine Tuberculosis. Glyn Hewinson. Lead Scientist. APHA. Presentation at EFSA Conference on Wildlife. 5th May 2015, Brussels.
  2. Impact of BCG vaccine on badgers
If you would like to send to me your comments, please contact me
Last Modified 13 May 2017 20:21
Javascript is disabled