VACCINATION AGAINST FOOT-AND-MOUTH DISEASE (FMD)

The facts about Vaccination

• EU legislation prohibits the use of “prophylactic” (routine vaccination) thus allowing the Community to retain its’ “FMD-free without vaccination” international trade status.
• The new EU Directive on FMD control permits the use of emergency vaccination as part of an FMD control strategy. The Directive provides for “suppressive” vaccination, which generally means that the vaccinated animals would subsequently be killed and “protective” vaccination which would allow the vaccinated animals to live out their normal economic lives.
• There are a number of different terms to describe vaccination strategies; for example, “ring vaccination” describes vaccination within a boundary drawn to circle an area of known infection. The size of the vaccination zone would depend on veterinary advice, the epidemiological situation (disease risk), geography and on available resources both in terms of vaccine supplies and human and other resources to carry out a vaccination campaign.
• Vaccination alone will not eradicate the disease in the face of an outbreak. In any event, EU legislation still requires the primary control measures of culling of all susceptible animals on Infected premises and dangerous contacts. If vaccination were subsequently utilised, it would need to be used in conjunction with measures such as movement restrictions and strict biosecurity.
• Vaccination cannot prevent disease in animals that are already infected or that become infected before immunity has developed following vaccination.
• Vaccinated animals that subsequently come into contact with live virus may become carriers of the virus. Such a carrier state may exist for over three years in cattle. Expert scientific advice is that spread of foot-and-mouth disease through the carrier state is a rare event but it is difficult to determine the precise level of risk. The issue of the carrier state affects international attitudes towards trading with countries that use vaccination.
• High strength vaccines (at least 6PD50) should start to provide some immunity from about four days after vaccination. Standard strength vaccines, of 3PD50 provide some immunity from about ten days after vaccination. Immunity declines after about six months.
• Serology (blood testing for antibodies to FMD) is the key tool in proving absence of disease in order to lift domestic and international trading restrictions. Conventional serology cannot distinguish between infected animals (including carriers) and vaccinated animals. Modern non-structural

protein (NSP) tests can distinguish between infected and vaccinated animals but these tests have not yet been internationally validated and are currently only suitable for use on a herd basis.

The Government’s position on vaccination

• The reports from two independent inquiries into the 2001 outbreak of FMD in the UK – Lessons to be Learned and the Royal Society Report into Infectious Diseases in Livestock – were published in July 2002. On 6 November 2002, the Government published its response to these two reports and this can be viewed at

www.official.documents.co.uk.document/cm56/5637/5637.htm

• Both reports recommended, and the Government accepts, that emergency vaccination should be considered as part of the disease control strategy from the start of any outbreak of FMD where measures additional to the culling of infected animals and dangerous contacts are needed. This should be on the basis of “vaccinate- to- live” wherever possible. However, both the reports and the Government acknowledge that there remain scientific and practical difficulties associated with a vaccination policy and the Government is working to overcome these, particularly through stakeholder engagement.
• As part of its Contingency Plan, which can be viewed at www.defra.gov.uk/footandmouth/contingency the Government has published a “Decision Tree” for foot-and-mouth disease control strategies. This reflects the fact that each disease outbreak is different and it is not possible to define precise strategy in advance of an outbreak. The “Decision Tree” sets out the criteria to be considered in determining choice of disease control strategy, including vaccination, depending on a range of factors.
• The Animal Health Act 2002 places a duty on the Secretary of State to consider emergency vaccination before exercising any additional preventive slaughter powers.

Vaccination in the new EU Directive on FMD control

• A new EU Directive on FMD control was adopted at Agriculture Council on 29 September and is required to be transposed into domestic legislation by 30 June 2004.
• The new EU Directive continues the prohibition on the use of prophylactic vaccination in the EU; this ban has been in place since 1992.
• The EU Directive requires the slaughter of all susceptible animals on infected premises and provides for the culling of susceptible animals on
• epidemiologically linked holdings (“dangerous contacts”). This reflects the EU’s policy of retaining its “FMD free without vaccination” status.
• However, the Directive moves vaccination to the forefront of disease control strategies, reflecting the recommendations made by the Inquiry Report into the 2001 outbreak in the UK. It requires that, immediately on confirmation of the first case of FMD, all necessary arrangements should be prepared for emergency vaccination in an area at least the size of the Surveillance Zone.
• The change in the emphasis placed on emergency vaccination as a disease control measure has been assisted by amendments to the OIE rules in May 2002, on the time required to regain FMD free status after the use of vaccination. FMD free status can be regained six months after the last case or the last vaccination (whichever is latest) where a “vaccinate-to-live” policy is utilised, providing that serological surveillance is carried out and that a serological survey based on the detection of antibodies to the non-structural proteins of FMD virus (NSP tests) demonstrates the absence of infection in the remaining vaccinated population. Where vaccinated animals are slaughtered, FMD free status can be regained 3 months after the slaughter of the last vaccinated animal; the same time-scale applies if a stamping out policy alone is used.
• The Directive contains a great deal of detail about emergency vaccination. According to the Directive, a decision to introduce emergency vaccination may be made when outbreaks threaten to become widespread, or when other Member States are at risk. Such a decision would normally be made by Standing Veterinary Committee procedure, either at the request of the Member State directly affected, a Member State at risk, or initiated by the Commission itself in consultation with the affected Member State.
• The Directive sets out criteria to be considered in the decision to apply a vaccination programme, including population density of susceptible animals; predominant species clinically affected; predicted airborne spread of virus; availability of suitable vaccine; incidence slope and distribution of outbreaks; public reaction to stamping out policy and acceptance of regionalisation after vaccination. The guidelines also indicate that emergency vaccination should be considered if it is forseeable that the targets of culling infected animals within 24 hours of confirmation and dangerous contacts within 48 hours cannot be met for two consecutive days. However, the decision to vaccinate will always be based primarily on veterinary and scientific advice in any given disease scenario.

If a vaccination programme were carried out, it would trigger movement restrictions and specific controls and treatments of products from vaccinated animals. These controls are detailed in the Directive and include heat treatment and deboning and maturing of meat from vaccinated animals before it can be placed on the market. However, a derogation permits the sale of untreated meat from vaccinated ruminants, as well as that from pigs, to be placed on the domestic market during Phase 3 of a vaccination campaign – that is, after completion of NSP testing to confirm absence of disease.

• The Directive provides for special measures to be applied in the case of zoos, wildlife parks and for the conservation of “farm animal genetic resources”, including provision for possible emergency vaccination. We are currently consulting stakeholders on the definition of “farm animal genetic resources”.

Contingency Planning

• The new Directive sets out the requirement for detailed contingency plans to be produced by each Member States, which must cover the “worst case scenario”, including precise indications of how emergency vaccination would be implemented.
• The Animal Health Act 2002 requires the Contingency Plan for England and Wales to be updated at least annually and laid before Parliament.
• Defra’s FMD Contingency Plan includes the operational arrangements in place for an emergency vaccination campaign.

UK Vaccine availability

• The UK holds independent supplies of eight strains of FMD antigen. This could be formulated into a high potency vaccine suitable for use in an emergency. In addition, the UK has access to vaccines held by the EU Vaccine Bank (EUVB) .
• The strains held by the UK are under constant review, taking into account the worldwide disease situation and expert advice on which strains pose the greatest threat to the UK.

Next steps: Issues to be resolved

• The availability of an internationally validated NSP test that distinguishes between vaccinated and infected animals is important to the acceptability of vaccination as a control policy and we are continuing to work with the EU and the OIE to achieve this. The OIE has established an ad hoc group to evaluate NSP tests for FMD and Defra is funding a three-year research project on FMD sampling strategies, including evaluating currently available NSP serological methods.
• In terms of logistics of a vaccination policy, the Defra Contingency Planning team are working hard to ensure the necessary arrangements are in place in the event of a need to vaccinate in a future outbreak.
• Marketability of products from vaccinated animals is another issue to be resolved if vaccination-to-live is to be a fully viable control option in the future. We have been in discussions with a wide range of stake-holders on this subject since the beginning of this year and we have formed a stakeholder sub-group one of whose objectives is to assist Defra in conveying messages on issues surrounding emergency vaccination such as the safety of products from vaccinated animals.

Why we did not vaccinate during the 2001 outbreak

• The primary objective was to eradicate the disease. Vaccination would have been used if the Government’s Chief Scientific Adviser and Chief Veterinary Officer had advised that it was the most appropriate measure of disease control in the circumstances.
• Vaccination was recommended in North Cumbria and possibly Devon to protect cattle before they were turned out from their winter sheds. However, only limited support for vaccination was gained from farmers, vets, consumers and the wider food trade. Industry was concerned about marketability of products from vaccinated animals and whether this would create a two-tier market.
• A mass, nation-wide vaccination programme was never proposed. Vaccination was considered at all stages of the outbreak, but scientific and veterinary advice remained that we would eradicate the disease most quickly and effectively through culling and tight biosecurity.
• Stakeholders were consulted throughout the decision making process on vaccination in the hardest hit areas.
• The essential support from farmers required for a vaccination programme to be carried out was not forthcoming as quickly as necessary. By the time action could have been taken, the number of new cases was falling and thus the need for vaccination diminished.

7 October 2003