The vaccine is intended to protect people against a strain of avian influenza called H5N1 that is spreading in Asia, Africa, the Middle East, and parts of Europe, and that could potentially lead to a global pandemic. The US Department of Health and Human Services (HHS) has made an initial $40m (€31m) order of bulk H5N1 antigen– the substance in the vaccines that will help produce an immune respons – to GSK. The new order will build on the existing US stockpile of about 5.9m doses of H5N1 vaccine. "Having a stockpile of influenza vaccine that may offer protection against the H5N1 virus is an important part of our pandemic influenza preparedness plan," said HHS Secretary Michael Leavitt. Under the terms of the contract, GSK will manufacture and store bulk H5N1 antigen using its recently acquired production facility in Canada. In addition, HHS may ask the drug maker to formulate the bulk antigen at some point in the future and HHS also has the option to purchase pre-pandemic vaccines together with one of GSK's proprietary adjuvant systems, which could mean that less antigen would be needed per dose to achieve a protective immune response, the company said. Clinical studies on the potential immunogenicity of a vaccine for pandemic flu using a GSK novel proprietary adjuvant system showed promising results. This announcement follows a previous deal signed in May between GSK and HHS, which awarded the drug giant with $274m to develop cell-culture technology to speed the development of new cell-culture-based seasonal and pandemic influenza vaccines, and to scale-up cell culture manufacturing capability at its Pennsylvania site. "We applaud the US government's proactive steps in protecting American citizens against this potential public health threat," said David Stout, president of pharmaceutical operations at GSK. "We are committed to helping governments and public health officials around the world effectively respond to the global threat of a flu pandemic and we are pleased to be working with the US government in its preparedness efforts." In addition, HHS announced it had also awarded contracts to two other drugmakers – Sanofi-Pasteur and Novartis – to supply flu vaccines. The three drug firms contracted will make enough doses to cover 2.7m people for $200m worth of vaccines against the H5N1 avian flu virus, HHS said. The US is one of several countries to sign a contract with GSK for a pre-pandemic vaccine and the company is reportedly in negotiations with the British government to provide vaccine for stockpiling purposes. With current global flu vaccine production capacity, most countries would not have access to vaccine once a pandemic begins.