extracting Influenza Virus Vaccine, Fluzone® from a 5 ml. vial.

Jim Gathany / CDC

Scientists around the world are testing human vaccines against the two most deadly strains of bird flu — H5N1 and H9N2 — to prepare for their predicted mutation into a form that causes a human flu pandemic.

But, as Erika Check reports in this week's Nature, this work might be futile if the pandemic virus turns out be vastly different to what scientists expect. If so, researchers will need to hurry to create a completely new vaccine.

Although some claim they could do this in just four weeks, Check points out that the time needed to manufacture the new vaccine would mean we would have far too few doses.

Check explains that pharmaceutical companies have little incentive to invest large sums of money making a vaccine for a pandemic that might never happen. Although governments could stimulate the vaccine market by encouraging the use of flu vaccines against non-pandemic flu, this overlooks another serious problem.

Developing countries in Asia, which are most likely to be the source of pandemic, have little capacity to make vaccines or buy stocks from other countries. Rich countries that hoard their supplies would make the problem worse. 

Public health experts say that sharing supplies seems to be the best option, but few countries are willing to discuss this proposal formally.

Link to full article in Nature 

Read more about bird flu in SciDev.Net's news focus, Bird flu: the facts.