Race is on for human vaccine against bird flu

Date: 06/04/06

scientists are racing to develop a vaccine to prepare for a theoretical future in which a bird virus becomes a contagious human disease. Vaccination may have come a long way since the 18th century doctor Edward Jenner discovered that the cowpox virus provided immunity to smallpox, but manufacturers still face considerable challenges.

In the event of a pandemic, manufacturers would have to be able to produce quickly a lot of vaccines for a human-to-human disease which as yet does not exist.

Last week (30 March) the France-based vaccine-makers Sanofi-Pasteur announced a breakthrough in the search for a vaccine against H5N1 - currently thought to be the most likely cause of a pandemic. Unfortunately, the vaccine they have developed worked on only half of the volunteers tested.

Even where a vaccine has been developed against a particular strain of disease, there is still a struggle to manufacture sufficient quantities.

EU manufacturers are in the vanguard both of the development of vaccines and their manufacture. They currently produce 70% of the world's vaccines, and export more than half of their production.

Of the 190 million doses manufactured in Europe last year, 100 million were sent abroad, most of them to South America, the Middle East, Africa and Asia.

The World Health Organisation currently recommends that 75% of high risk groups should be vaccinated every year against normal seasonal flu - a target that is not met in most member states. The European Vaccine Manufacturers (EVM) estimate that 33% of the population needs to be vaccinated to protect the 450 million people living in the EU today . This would mean increasing production from 90 million doses at present to 150 million.

Manufacturers do not have the luxury of devoting all their time and resources to searching for a new vaccine against H5N1, since the standard annual flu jab also has to be developed.

Since viruses mutate all the time, last year's vaccine can no longer be used and an updated version has to be prepared for the market.

Which illustrates another problem with developing an avian flu jab: if a vaccine was developed it could not be stored for long and would need constantly updating in the light of subsequent mutations.

Manufacturers are currently working on prototype vaccines using mock malevolent vaccine strains, in preparation for the possible emergence of a virulent strain. Each prototype costs at least EUR 11 million.

In the event of a pandemic, the actual pandemic vaccine strain could - in theory - quickly be substituted for the mock.

The annual influenza vaccine takes up to six months to develop and to place on the market. To make sure that, if a pandemic occurs, the appropriate vaccine is on the market as quickly as possible, manufacturers and the European Commission have agreed a faster-than-usual approval system, termed the "abbreviated registration procedure".

It would cut out some of the clinical trials needed for a standard influenza jab. Because of this, EVM have also asked the EU to agree the necessary legal changes that would temporarily waive manufacturers' liability for a pandemic vaccine.

Author reports on the challenges of producing a vaccine on a large scale, which had yet to be transmitted between humans.
Article is part of a European Voice Special Report, 'Pandemics'.

European Commission: DG Health and Consumer Protection: Animal Health & Welfare: Avian Influenza - introduction http://ec.europa.eu/comm/food/animal/diseases/controlmeasures/avian/index_en.htm

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