USA-based groups Baxter and Chiron have won contracts to supply the UK government with around 3.5 million doses of H5N1 vaccine, in order to help strengthen the country’s defences against a potential pandemic outbreak of bird flu.

Announcing the contracts - worth £33 million - at a special meeting of European ministers in Vienna on Friday, UK Health Minister Rosie Winterton said: “Building a stockpile will allow us to carry out more research and [the vaccine] could be offered as a possible first-line defence for National Health Service workers whilst the exact vaccines to match the pandemic flu strain is manufactured. In addition, this is in addition to placing sleeping contract for 120 million doses of pandemic vaccines, which will ensure access to the vaccines once it is developed.”

The H5N1 strain of bird flu has already claimed the lives of at least 92 people and has infected many more since its re-emergence in 2003. Although, so far, it has primarily been birds in Asia that have been affected, the virus has already crossed the borders of Europe - the latest possible outbreak currently being investigated in turkeys at a farm in France. Experts fear that the virus will mutate to become easily transmissible from person to person, an event that would almost certainly fuel a pandemic outbreak and, potentially, cause hundreds of thousands of deaths around the globe.

Chiron, which is in the process of being taken over by Swiss drug major Novartis, has recently filed an application with the European Medicines Agency for a ‘mock-up vaccine’ before the outbreak of a pandemic, which allows for the actual strain responsible, once identified at the time of the outbreak, to be incorporated into the core dossier.

The group also has a contract to supply the US government with pre-pandemic influenza vaccine for its stockpile, and has just received an extension to complete this order. The company says it now expects to complete production of around 70% of the US government’s order at its Liverpool plant in the UK before March, when it will break from manufacture temporarily to focus on making its seasonal flu vaccine, Fluvirin.

Meanwhile, the company announced that, subject to the closing of its acquisition by Novartis, German drugmaker Schering AG intends to exercise an option to buy back or lease Chiron’s Betaseron (interferon beta-1b) manufacturing assets. Betaseron, global sales of which rose 12% to 240 million euros ($286m) in the fourth quarter of 2005 despite mounting competition, is approved for relapsing forms of multiple sclerosis, and has recently been filed with US regulators by Schering’s subsidiary Berlex for the treatment of early forms of the illness.