WRITTEN QUESTION E-0972/97 by Leen van der Waal (I-EDN) to the Commission (13 March 1997)

Subject: New vaccine against swine fever

NRC Handelsblad reported on 15 February 1997 that the institute for animal husbandry and animal health (ID-DLO) at Lelystad had developed a marker vaccine against swine fever. Bayer and the ID-DLO anticipate that the registration file will be submitted before the end of this year to the European body responsible for the registration of veterinary drugs.

1. Does the Commission share my view that the use of marker vaccines can largely eliminate the objections to vaccination in relation to international trade, as vaccinated animals can easily be distinguished from animals infected with swine fever?

2. Does it share the view that in areas with large pig populations marker vaccines can play a useful role in combatting swine fever, to supplement other necessary measures such as a complete registration system and the achievement of closed holdings or areas as far as possible?

3. If so, is it willing to fund research into the desired efforts to prevent and combat the disease in such areas and the possible role of marker vaccines?

4. Is the Commission willing to give priority to dealing with the registration application for a marker vaccine which Bayer is to submit shortly?

Answer given by Mr Fischler on behalf of the Commission (16 May 1997)

1. When considering the use of a marker vaccine or a conventional vaccine against classical swine fever, it must be taken into account that the so-called carrier sow syndrome is of special importance in relation to the control and eradication of this disease. When pregnant sows are exposed to strains of low or moderate virulence, the infection may initially go unnoticed but the virus can be transmitted to the foetuses in the uterus. Depending on the stage of pregnancy and the virulence of the virus strain, the sow may later abort or produce mummified piglets, weak piglets or piglets which appear to be born healthy. Large amounts of virus may be disseminated at farrowing. The apparently healthy piglets, from an epidemiological point of view, can be the most insidious of all. These piglets may shed large quantities of virus for months without showing signs of disease or developing an immune response. Vaccination of carrier sows has in the past not been able to prevent the birth of piglets carrying the virus.

When applying vaccination, it must furthermore be kept in mind that the immune response, being a biological process, never confers absolute protection under field conditions nor is it equal in all pigs in a vaccinated population. The immune response tends to follow a distribution whereby the response in most pigs will be average, in a few will be excellent and in a small proportion will be poor. Those with a poor response may not be protected by an effective vaccine.

The biological aspects of vaccination described above appear to be the same and independent of the use of a marker vaccine or a conventional vaccine. This means the reservations on the use of vaccination can most likely not be eliminated by using a marker vaccine. The development of a marker vaccine, defined as a vaccine that can elicit a protective immunity distinguishable from the immune response elicited by the natural infection with the wild type virus, can overcome the problem relating to the difficulties existing at present in interpretation of seropositive reactions in animals which have an unknown vaccination status. This sole but unique characteristic, however, will not be able to eliminate a number of the disadvantages connected with the use of vaccines in the eradication of classical swine fever.

2. The legislation proposed in 1991 by the Commission and adopted by the Council on Community measures for the control of classical swine fever took into account that vaccination might be required in an emergency situation. In Article 14 of Council Directive 80/217/EEC ((OJ L 47, 21.2.1980. )) the conditions for use of vaccines are described in detail. The provisions of Directive 80/217/EEC have since 1980 been amended eight times to reflect progress in laboratory diagnostic techniques and other developments important for the control of classical swine fever in domestic pigs and wild boar. At present there are still open questions concerning the ultimate efficiency and safety of marker vaccines being developed and not yet registered. When further information is available on these topics it will be taken into account when an up-date of the legislation is carried.

3. The Community has several programmes concerning funding of research and technological development. In the event a research project on the development and use of a marker vaccine or on the control of infectious diseases in densely populated livestock areas is received for funding within these established programmes, the project in question will be evaluated in accordance with the normal procedures. The Commission has in the past provided financial contribution for research projects, which deal with development or improvement of a vaccine to control a disease for which the Community legislation does not foresee use of vaccination or emergency vaccination only.

4. There is no provision in the current rules for a fast-track procedure to deal with applications for Community authorization of veterinary medicinal products. However, it should be pointed out that the procedure normally only takes a relatively short time (roughly 10 months) and that the time required for scientific evaluation can be reduced still further if the monograph submitted by the firm is of high scientific quality.