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Bovine TB Vaccination

Bovine TBPosted by Susan Hooper Wed, March 20, 2013 19:28:19
Submission to the Environment, Food and Rural Affairs Committee 
Inquiry examining the vaccination of badgers and cattle in relation to Bovine TB 

1. Introduction. 
1.1 Rethink Bovine TB is an independent group with an interest in agriculture, animal diseases, animal welfare and the financial viability of farming. 
1.2 We confine our submission to vaccination of cattle against Bovine TB and Defra’s recent handling of associated regulatory issues. 

2. Summary. 
2.1 Paradoxically vaccination against Bovine TB was banned so that Bovine TB could be detected. 
2.2 Defra’s claims for vaccine efficacy are misleading as they ignore the way vaccines work in a herd to stop the spread of disease. Defra have not modelled the effect of vaccination on herd breakdowns. 
2.3 Defra had scheduled all regulatory work except changing EU law for completion in 2012. The vaccine and DIVA test are ready but not licensed or approved because Defra had not appreciated the requirements. 
2.4 Little has been done to change EU law to enable vaccine use. 
2.5 Enquiries into the delays and reasons for delays have been evaded by a Defra Minister and by civil servants. 
2.6 Defra only realised around 2011 that a vaccine could not be licensed until the EU ban on use had been lifted. 
2.7 Defra were taken by surprise when the OIE demanded field trials which would involve vaccination in the field which is illegal. Defra have still not decided whether to try to perform the trials, putting the whole programmer in doubt. 

3. Cattle Vaccination 
3.1 The principal means of preventing epidemics and protecting against infectious diseases is almost always vaccination. Bovine TB in cattle is an exception only because vaccination was made illegal as the readily available vaccine, BCG, interferes with the test used to detect the infection. In other words the leading solution to BTB, vaccination, was banned so BTB could be detected. 
3.2 However a “DIVA” test which distinguishes between vaccinated and infected cattle is now awaiting approval, and work to enable licensing of BCG (a vaccine used on humans for many decades) as a cattle vaccine is complete. 
3.3 Although modelling data is scarce it would be reasonable to expect vaccination to produce a dramatic reduction in the number of herd incidents and individual cattle slaughtered, even at the lower estimates of vaccine efficacy. 

4. Efficacy of cattle vaccination 
4.1 The results of the majority of studies of BCG use on cattle have demonstrated considerable protection with field studies in Mexico and Ethiopia indicating 56 – 68% protection of individuals. (Note that this is often incorrectly rounded down to 50 - 60%. Correctly rounded it becomes 60 – 70%). 
4.2 Defra repeatedly caution that BCG will not provide complete protection. As for any vaccine this is correct, but very misleading because of the way vaccines work in a herd. 
4.3 There are two reasons for vaccinating against infectious disease: 
a. To protect an individual. Any protection helps but as near 100% as possible is preferable. 
b. To protect a population. It is only necessary to achieve a level of immunity at which that the disease cannot spread through the population, and goes into decline – the herd immunity threshold. Less than full protection of each individual is generally sufficient, and not every individual need be vaccinated. 
4.4 For cattle the aim is to protect the herd so the disease goes into decline, not to protect any one individual animal. 
4.5 Any level of efficacy will help reduce incidence, even if herd immunity is not achieved. 
4.6 Defra claim that “It is not clear what effect BCG vaccination of cattle would have in reducing the incidence of TB herd breakdowns.” 
4.7 Why has no modelling of this critically important aspect been carried out for Defra? 
4.8 Further unanswered questions include: 
4.9 What efficacy would be needed to achieve herd immunity? 
4.10 What would be the equivalent efficacy if vaccination was combined with other measures, such as properly designed and enforced cattle movement protocols? 
4.11 What efficacy, using cattle vaccination alone, would be needed to achieve the same effect as the current policy? 
4.12 If vaccination was used alongside the existing test and cull policy (obviously with use of the DIVA test) what reduction in the number of cattle slaughtered could be expected? 

5. Progress 
5.1 Defra included the following statements in their September 2010 Consultation ; 
5.2 “We aim to have a licensed cattle vaccine by 2012” 
5.3 “Our aim is also to have the DIVA test approved by 2012” 
5.4 “Due to the need to change EU legislation, which is a lengthy process, we anticipate that a cattle vaccine and DIVA test could not be used in the field before 2015.” 
5.5 From this, Defra had scheduled a 2012 completion for all scientific and regulatory work. 
5.6 The remaining obstacle would be EU legislation. 

6. Current Status under EU law 
6.1 The ban on cattle vaccination was introduced because the BCG vaccine can interfere with the Tuberculin skin test. This is no longer a problem because of the DIVA test. Yet we cannot repeal the obsolete law ourselves, but must go cap in hand to the European Commission. 
6.2 It is not clear why Defra thought 2015 marked a watershed in changing EU law. They were hoping that proposed new animal health legislation might allow vaccination of cattle against BTB but they admit they have no control and limited influence. 
6.3 If changing EU legislation is as Defra claim “a lengthy process” Defra should have started the “lengthy process” at the same time as work on the vaccine and DIVA test. 
6.4 In Defra’s September 2010 consultation they stated at Para 63: “As part of the ongoing consultation on the new EU Animal Health Law, we will be using the strong scientific and technical evidence on the efficacy and safety of the cattle vaccine and the role of a DIVA test to request the necessary changes to EU legislation........”. 
6.5 In the “Bovine TB Eradication Programme for England July 2011” Defra state at Para 87: “We will be using the scientific and technical evidence on the efficacy and safety of the cattle vaccine and the role of a DIVA test to press the case in Europe.........”. 
6.6 The use of the definite article in “The strong ............. evidence” and “The ............ evidence” implies such evidence already existed. The repeated term “We will be” clearly means we have not yet. 
6.7 From Para 88 of the same 2011 document: “Changing EU legislation is a lengthy and uncertain process and preliminary discussions with the EU Commission have indicated that a change to the legal framework on vaccination and DIVA testing cannot be considered until sufficient evidence of their effectiveness is available. This is likely to take some time and as a result we anticipate that a cattle vaccine and DIVA test will not be available for use in the field for many years.” 
6.8 Does “cannot be considered” mean cannot be lobbied and prepared for, or cannot be implemented? The former meaning seems to be the one accepted by Defra. The latter is the likely reality. We note that “...until sufficient evidence of their effectiveness is available” contradicts “the strong scientific and technical evidence” in the 2010 consultation quoted above. 
6.9 The 2015 target has become an indeterminate delay of “many years”. The vaccine and DIVA test are ready for licensing, but little or nothing has been done to change the law to allow approval and use. 

7. Correspondence with the Minister of State 
7.1 Letters from Jim Paice, (when Minister of State) in reply to correspondence with Mark Williams MP failed completely to explain what steps have already been taken to change EU law. After ignoring the EU aspects the then Minister finally (letter 19 March 2012) discusses procedure for changing EU law, still ignoring the question. 
7.2 If the Minister ignores the question, one would assume no action has been taken. 

8. FoI Requests 
8.1 Requests under FoI 2000 were fielded with a more direct and honest form of evasion – simple refusal to answer difficult questions. 
8.2 “When we came to publish the [TB] Eradication Programme [July 2011] it was clear that significant technical and regulatory challenges remained and this led us to conclude that the 2015 date should be dropped until matters had been clarified. We still do not have a fixed date by which we expect cattle vaccine to be deployed in the field. However, the details underpinning these uncertainties as requested in your freedom of information request are withheld under exemptions 27 (international relations) and 35 (formulation of government policy) of the Freedom of Information Act.” 
8.3 We have been unable to establish what the “significant technical and regulatory challenges” are, nor how they might affect international relations and formulation of government policy. 

9. Licensing and Approvals 
9.1 In RFI 4469 Defra admitted “By the time we came to publish the TB Eradication Programme in July 2011 we were aware that a TB cattle licence could not be issued by the Veterinary Medicines Directorate until the ban on vaccination had been lifted” 
9.2 Why were Defra not aware of this crucial information from the outset? 
DIVA Test 
9.3 Before (and if) the EU lifts the ban on vaccinating cattle against BTB, the DIVA test must be approved by the OIE. Defra submitted an application following Easter 2012. This was rejected by the OIE as no UK field trial data was submitted. Field trials cannot be conducted in the UK without a derogation from the EU because vaccination of cattle is illegal under EU law. 
9.4 Why did the demand for field trials take Defra by surprise? It should not have done. They were aware of the potential requirement long ago when the Vaccine Advisory Group highlighted the absence of experimental systems to measure vaccine efficacy in a natural transmission setting. In 2005 Defra announced the necessary research, albeit to be done in contained facilities not as field research. 
9.5 In any properly organised development programme, approval and licensing is discussed with the regulators at every stage in development. Any element that would not be approved is altered or dropped and all trials the regulator requires are designed into the programme at every stage. In most cases licenses or derogations can be obtained for necessary veterinary research which would otherwise involve illegal acts. 
9.6 Why did Defra not discover in advance the OIE requirement for field trials and corresponding need for an EU derogation? 
9.7 It appears that the vaccine licence cannot be issued unless the vaccination ban is lifted; The vaccination ban cannot be lifted; Until the DIVA test is approved; Which cannot happen until field trials are conducted; Field trials cannot be conducted until the vaccination ban is lifted. 
9.8 The matter was further confused by FoI 5189 of 19 December 2012 , in which Defra stated: “But as yet no decisions have been taken on whether or not to undertake experimental or field trials.” 
9.9 This is a shambles, and one which Defra must have foreseen yet failed to prevent. 

10. Conclusions and Recommendations 
10.1 The test and cull strategy has failed to achieve OTF status and arguably has worse effect than the disease itself. The only proportionate solution likely to achieve better results is cattle vaccination. 
10.2 Defra’s attempts to achieve regulatory and legal approvals for vaccine use have descended into farce. 
10.3 Defra Ministers must put an end to this and order officials to find solutions - not create more bureaucratic muddles - so as to deploy cattle vaccination without delay." 

11. Postscript The 2010 Rethink Bovine TB report “Bovine TB: Time for a Rethink” concluded that: 

Bovine TB is not a significant human health risk in the UK. Hardly anyone catches Bovine TB from cattle or cattle products in the UK. 
The effect on animal welfare, and on farmers, of cattle testing and culling is worse than the disease itself. Farmers should be free (or required) to vaccinate cattle.
Milk pasteurization and meat inspection should continue. 
The tuberculin skin test is woefully inaccurate, even worse than generally believed.
Some 60 years from introduction the test and cull policy has failed. 10 January 2013

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