US Orders More H5N1 vaccine

The US government has awarded three more contracts to buy and stock sufficient H5N1 avian influenza vaccine that can immunize almost 2.7 million people, at a cost of $199.45 million.

According to the Department of Health and Human Services (HHS) the contracts are for a total of 5.3 million 90-microgram (mcg) doses of vaccine. The awards include $40.6 million to GlaxoSmithKline (GSK) for 800,000 doses, $40.95 million to Novartis for 800,000 doses, and $117.9 million to Sanofi Pasteur for 3.7 million doses.

According to HHS the existing national stockpile of pre-pandemic vaccine is only sufficient to vaccinate about 3 million people with two 90-mcg doses each. And of the stockpile of 7.3 million doses, around 1.4 million doses have begun to lose potency, leaving 5.9 million doses of full-strength vaccine.

HHS said, "These newest vaccine purchases supplement the existing stockpile of 5.9 million doses of H5N1 vaccine and build on the department's plans to buy enough vaccine for 20 million people."

Sanofi Pasteur stated that its new contract is for a vaccine based on a clade 2 (subgroup 2) H5N1 virus. The existing stockpile is based on clade 1 viruses, which circulated and caused human cases in Thailand, Vietnam, and Cambodia in 2004 and 2005. Clade 2 viruses circulated in birds in China and Indonesia in 2003-04 and spread to the Middle East, Europe, and Africa in 2005 and 2006.

Last week HHS noted its intention to begin stockpiling vaccine based on clade 2 viruses, during its pandemic planning, because of concerns that a vaccine based on one clade won't work well against a pandemic strain stemming from a different clade.

HHS’ announcement follows fewer than 3 weeks after health experts assembled by the World Health Organization warned governments against rushing to stockpile pre-pandemic flu vaccines, stating that several scientific uncertainties remain. According to these experts vaccines that work against one clade may not work against others and that the level of measured immune response representing adequate protection is unknown.

According to Sanofi Pasteur, which has a vaccine plant in Swiftwater, Pa.,its new contract is worth "up to $117.9 million," the final amount depending on the number of doses that can be made from the bulk vaccine. The company said, "The bulk concentrate is being produced now. Potency testing will be conducted over the next few months to determine the concentration of the bulk material."

In addition to its $13 million contract in September 2004 to make 2 million doses of H5N1 vaccine Sanofi also won a $100 million contract in September 2005 to make more of the vaccine. According to the company statement today that contract is worth $150 million.

Novartis has planned to make the H5N1 vaccine at its plant in Liverpool, England, in 2007 after production of next year's seasonal flu vaccine is finished.

The statement said, "The US government will determine the dosage and formulation of the final product, including potentially adding an adjuvant such as MF59, at a later date."

Novartis had acquired Chiron Corp earlier this year, which had won a $62.5 million H5N1 vaccine contract award from HHS in October 2005.

GSK reported that the company would make bulk H5N1 antigen at its "recently acquired production facilities in North America." Under the contract, GSK said, HHS may require that the vaccine include an adjuvant, which could reduce the amount of antigen needed per dose. Preliminary results of a clinical trial of an H5N1 vaccine with a novel adjuvant appeared to be promising according to the company’s statement.

Source-Medindia
NLA