The British government has signed agreements with vaccine manufacturers to secure supplies of up to 90 million doses of pre-pandemic H1N1 vaccine before a pandemic begins, the Department of Health announced on Friday.

The deals signed between Alan Johnson, Secretary of State for Health, and GlaxoSmithKline and Baxter, will enable production of pre-pandemic vaccine to begin as soon as possible.

The agreements could provide enough vaccine to protect the most vulnerable in our population before a pandemic is likely to arrive, without affecting the country's supply of seasonal flu vaccine.

Johnson, the Secretary of State for Health, said: "The localized cases of swine flu found in the UK have so far been mild, and our strategy of containing the spread with anti-virals appears to have been effective in reducing symptoms and preventing further spread of infection.

"Scientists tell us that as yet we don't know enough about this novel strain, or whether it's likely to mutate, but that this virus has the potential to become a pandemic and we can't predict how serious that would be. We have an opportunity to secure vaccine in advance of a pandemic wave. We have Advance Purchase Agreements to provide vaccine for the entire UK population which will take effect when Phase 6 pandemic is declared. It will then take over a year for all the vaccine necessary to be provided."

The additional arrangements provide the opportunity by December this year to have enough pre-pandemic vaccine to protect at least half of the British population from swine flu. However, Johnson added, this will depend on when and if the manufacturers switched from seasonal to H1N1 pandemic specific vaccine production at a time after Phase 6 is declared by the World Health Organization (WHO), "as this will take precedence over pre-pandemic contracts."

The pre-pandemic vaccine is made from the current seed strain. If WHO declared a pandemic, this would then become the pandemic specific strain.

If a pandemic is declared, Advance Supply Agreements signed by the government with GSK and Baxter in July 2007, will enable the country to purchase up to 132 million doses of pandemic specific vaccine, when it becomes available.

Under the agreement, by December this year enough pre-pandemic vaccine to protect frontline health and social care workers, older people, those in clinical risk groups, and children with some additional flexibility could be secured.