US orders more bird flu vaccine for the stockpile

The U.S. government has ordered enough vaccine to protect another 2.7 million people against bird flu.

The Department of Health and Human Services (HHS) has signed contracts totaling $199 million with Novartis AG, Sanofi-Pasteur and GlaxoSmithKline PLC for 5.3 million doses; two 90-microgram doses make up one vaccination.

The U.S. stockpile originally had enough doses to vaccinate 3.75 million people against the deadly H5N1 bird flu virus, however during routine testing of the stockpile, Sanofi found that nearly one fifth of the doses had already lost their effectiveness and the stockpile only had the potential to vaccinate 3 million people.

The H5N1 virus is in a constant process of mutating and the stockpile was meant as a defence against a class of the virus called Clade 1.

But a new variant which appeared recently called Clade 2, has prompted the need for the development of doses to protect against it and a new supply of vaccine.

The avian influenza virus H5N1 is a subtype of the common influenza virus A which affects humans and other animal species.

The virus has in the main affected birds around the world and the center of most of the outbreaks has been Southeast Asia.

The H5N1 virus first appeared in poultry in Asia in 2003 when it killed almost 150 people worldwide.

The disease remains one which is at present confined to birds, and cannot be transmitted between humans or through aerial transmission.

Almost all those who contracted the deadly virus did so by handling sick or infected birds.

Indonesia has been the center of the disease and the Clade 2 version of the virus has already appeared in birds in China and Indonesia in 2003-2004.

But this year the virus has moved on to the migratory and wild birds of Africa and Europe.

There has always been concern that the virus will continue to mutate until transmission among humans is possible along with the ensuing threat of a pandemic.

This has prompted many countries to stockpile vaccines against H5N1.

The U.S. government eventually plans to build a stockpile capable of vaccinating 20 million people and have asked manufacturers to produce the vaccine in cells rather than in eggs, as cell based production would be quicker in the event of a pandemic.

The HHS has also requested that the vaccine include an adjuvant which would make the vaccine go further.