Newcastle Disease (La Sota Vaccine) (Hansard, 5 August 1971)

§ Mr. Prior

My right hon. Friend the Secretary of State for Scotland and I have now received the advice of the Ministry's Chief Veterinary Officer and a report by the Fowl Pest Review Panel, including the independent members, recommending that the La Sota vaccine should be authorised for general use without delay. We have accepted this advice, and licence applications from manufacturers will be considered immediately. I am circulating the Report of the Review Panel in the OFFICIAL REPORT.

Sufficient evidence is now available from the Ministry's field trial, the research by the Central Veterinary Laboratory, including the preliminary results of the trials carried out in co-operation with the Game Conservancy, and the experience of field use of the vaccine in the Netherlands to show that the vaccine if correctly applied has no untoward side effects on birds, domestic or game. It is clear that La Sota vaccine, like the inactivated vaccine, when used as a booster dose, provides substantially greater and longer-lasting protection than the Hitchner B1 vaccine; and it has the advantage over the inactivated vaccine that like the Hitchner B1 it is much easier and cheaper both to manufacture and to use. These advantages, which it is now clear can be achieved with safety, offer the industry an opportunity to achieve an effective and higher national coverage, and consequently a greater degree of protection, to deal with any possible resurgence of the disease in the autumn.

We shall be issuing an advisory leaflet very shortly giving simple, standard, advice on the use of the various vaccines available, and on the development of vaccination programmes. But conditions and circumstances vary from flock to flock and if flock-owners are in any 462W doubt they are strongly advised to consult their veterinary surgeon.

Following is the report:

La Sota Vaccine

Interim Report of the Fowl Pest Review Panel 1. In reviewing the measures for the control of fowl pest we have given priority to the question whether to recommend Ministers to authorise the use of La Sota live vaccine. We regard a decision on this question as a matter of urgency. The number of confirmed outbreaks has declined markedly in recent weeks but this may well be attributable not only to such factors as seasonal changes and climatic conditions but also in some measure to the reluctance of poultry-keepers to report the disease. The risk of a resurgence of disease in the autumn is still a real one. If the use of La Sota is to be authorised the decision should be taken in good time to enable producers to include this weapon in their armoury before the onset of less favourable climatic conditions in the autumn. 2. This means that a decision should be taken without delay. If the use of the vaccine were authorised it would take some time for supplies to be licensed under the Diseases of Animals (Therapeutic Substances) Order 1952—and also under the Medicines Act 1968 in respect of any vaccines not effectively on the market on 1 September—and subsequently to appear on the British market. The approval of protocols to manufacture may involve additional tests which could mean a delay of 3/4 weeks before licences could be issued. Once licences have been issued it is expected that supplies will rapidly become available. If the decision were not to approve La Sota it is equally desirable that it should be made soon since the demand for inactivated vaccine which has increased in recent weeks would be further stimulated and the production period for this vaccine is a prolonged one. 3. Since the general use of Hitchner B1 live vaccine was authorised by Ministers last December very large quantities of it have been sold. Compared with the inactivated vaccine it is much more easily administered and does give some protection to very young birds. The immunity it provides is however of limited and variable duration and a high degree of maternal antibody interfers with its immunising capacity. The La Sota vaccine is not only easier to administer but has the advantage of giving a higher level of immunity which is also of longer duration. It is against this background that a substantial body of producer opinion has urged the use of La Sota vaccine under various conditions. In fact although no firm evidence is available it has been widely suggested that some producers have obtained La Sota vaccine illegally and are using it on their flocks. 4. The Ministry trials of La Sota vaccine have reached a point where the main conclusions can be drawn, and the use of La Sota vaccine in the Netherlands has been studied by Ministry experts. Combined with the results of research carried out by the Central 463W Veterinary Laboratory at Weybridge this evidence has provided the basis for the advice we have received from the Chief Veterinary Officer of the Ministry. His advice is that while La Sota vaccine is not suitable for use in very young birds and should only be used in primary vaccination under very exceptional circumstances it can fill a useful rôle later in a vaccination programme to boost the level of immunity obtained by the initial vaccination with Hitchner B1 or inactivated vaccine. Used in this way La Sota vaccine does not appear to have significant side effects The vaccine virus can spread from bird to bird within a flock but there is no evidence to suggest that it can spread from one premises to another. 5. On the basis of this advice we are satisfied that the La Sota vaccine should be authorised for general use. A number of organisations have suggested to us that further trials, particularly with broilers and game birds, should be undertaken before the vaccine is finally approved for general use. If authorisation were postponed until further trials had been undertaken a decision would have to be put off for six months until well after the autumn when the risk of a possible new epidemic can arise. So far as game birds are concerned the preliminary results of the trials which are being conducted in co-operation with the Game Conservancy have shown that the vaccine has produced no untoward side effects in vaccinaed or contact birds. Similar results have been obtained with turkeys. 6. We have also very much in mind that there is no control of the quality of any La Sota vaccine which has been imported illegally and is in use in this country. In our view it would be better for the industry to have vaccines which are subject to quality controls and on which there can be free discussion and advice about methods of administration. 7. It has also been suggested to us that the La Sota vaccine should be authorised for use only under veterinary supervision. The only way in which this would be at all practicable, without impossible demands on veterinary manpower, would be to supply the vaccine only to veterinary surgeons in private practice and to permit them to sell it to producers and to supervise its administration. This is the method which has been tried in the Netherlands but it has not in practice proved effective in ensuring veterinary supervision. If veterinary supervision is insisted upon it must add to the costs and would we fear act as a disincentive to vaccination. We are confident that with proper advice and instruction the owner will readily undertake his responsibility to see that the vaccine is administered properly and will consult his veterinary surgeon if he is in any doubt about the method of administration. 8. We attach great importance however to ensuring that producers receive adequate advice on programmes and methods of administration of N.D. vaccine. The Ministry are ready to take active steps in conjunction with the industry to provide advice to producers by leaflets and all other practicable means. We recommend that these measures should be as comprehensive and achieve as wide a coverage as possible. It is important that this campaign should be got under way at the earliest possible date.

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Conclusion 9. In our view the general use of La Sota vaccine if properly administered would make a major contribution in protecting the industry during the coming winter. It should therefore be authorised for general use in Great Britain without delay. We see no reason why producers in Scotland should be prevented from using the vaccine and such prohibition would not in any event be practicable. 10. There is no reason to expect that exports of live poultry would suffer in consequence of the use of La Sota vaccine in this country; the use of live N.D. vaccine is now common practice in overseas countries. 11. Finally, we would recommend that arrangements should be made in co-operation with the industry for monitoring the use of La Sota vaccine, and for a review of experience with the use of the vaccine which could be of value in providing producers with advice on the best use to be made of the weapons of protection at their disposal.