Drugmakers have been boosted by the news that US health regulators have approved six versions of a vaccine for the 2008-2009 flu season, targeting three new strains, but the firms could have their work cut out to meet demand.

The vaccines given the thumbs-up by the US Food and Drug Administration are Afluria (manufactured by CSL), Fluarix (GlaxoSmithKline), FluLaval (GSK unit ID Biomedical Corp of Quebec), FluMist (AstraZeneca unit MedImmune), Fluvirin (Novartis) and Fluzone (Sanofi Pasteur). The FDA changed all three strains (two from type A, an H1N1 and an H3N2 version, and one for type B) for this year's influenza vaccine, which it notes is “an unusual occurrence”, as usually only one or two strains are updated from year to year. Two of the three strains recommended are now in use for the Southern Hemisphere's 2008 influenza season.

Aparna Krishnan, an analyst at Global Insight, noting last year's low protection rate, says that the FDA “seems to have taken a cautious stance in including additional flu virus strains. The agency’s Centers for Disease Control and Prevention has said that the overall protection rate last year was just 44%, and “it is clear that last year's experience has increased pressure on the CDC and the FDA to act”, she claims.
The recommendation is particularly good news for Sanofi Pasteur and MedImmune. The former has initiated a shipment of 1.3 million doses of FluZone, a figure which is expected to rise to 50 million, while the AstraZeneca unit said this week that it plans to produce 12 million doses of FluMist, its nasal vaccine, for the 2008-2009 season.

In total, the manufacturers are expected to produce a record total of 143-146 million doses of flu vaccine for the US market, up from 140 million last year. Ms Krishnan notes that the manufacturing of vaccines for the new strains has presented challenges for companies as producing more than 100 million doses “usually requires a lead time of about eight months, with a potential rise in procurement as the winter months set in”.

However Sanofi Pasteur for one is confident it can cope. Chief executive Wayne Pisano said that the Introduction of three new strains “was unprecedented and could have resulted in a low yield or delay given our tight production timeline”. Still, “despite these challenges, we are pleased that once again Sanofi Pasteur has demonstrated its reliability in supplying Fluzone”, he added.