Farming News - New analysis shows vaccinating badgers has two-fold benefit
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New analysis shows vaccinating badgers has two-fold benefit
A new analysis of a four year field trial on TB vaccinations in badgers reveals that it reduced the risk of a positive result to a triple diagnostic test by 54% in vaccinated badgers. Vaccination was associated with a significantly lower risk of an individual badger testing positive to either of two diagnostic tests carried out for TB infection. However, the authors of the report caution that it is unsafe to assume that negative results to the tests mean that the animals were definitely free of the disease.
The trial was carried out in a 55 Km2 area of Gloucestershire between November 2005 and October 2009. The report is co-authored by researchgers from The Food and Environment Research Agency, the Department of Bacteriology, Animal Health and Veterinary Laboratories Agency, the School of Biology, University of Newcastle, the Department of Mathematics and Statistics, University of Strathclyde, and the Environment and Sustainability Institute, University of Exeter.
"Herd immunity"
One of the challenges for controlling TB in badgers by vaccination has been ensuring that a significant proportion of individuals are treated and that badger cubs, because they tend not to leave the sett for the first two months, can evade immunisation. But, one aspect of the study demonstrated a significant indirect effect of vaccination by conferring "herd immunity" to otherwise susceptible badger cubs. The authors argue that unvaccinated badger cubs were indirectly protected from the disease through a "herd immunity" effect at least up to the point when they come above ground and could be trapped and vaccinated.
The report concludes that vaccination of badgers is beneficial in at least two ways; by directly reducing the burden of TB in vaccinated individuals and by indirectly reducing the risk of infection in unvaccinated cubs. This indirect protection to cubs, the authors argue, could be an important contribution to the success of vaccinating wildlife.