WHO will take vaccine gamble with swine flu

[I am definitely getting the impression that they are mostly concerned about this Swine Flu mutating into a more deadly strain this Fall. The last sentence says it all. So if they are willing to go to these lengths, they must feel it has a good chance of evolving.]

LONDON — When World Health Organization officials ask vaccine manufacturers to start producing vaccine to fight swine flu in a few weeks, they will be taking a calculated risk.

Flu vaccine companies can only make one vaccine at a time: seasonal flu vaccine or pandemic vaccine. Production takes months and it is impossible to switch halfway through if health officials make a mistake.

While some countries like the United States may be better prepared than others – American officials say production for next year's vaccine batch is so advanced they're nearly finished – the situation for many other countries is unknown.

-snip-

"It's a big decision...We've never done this before," said Marie-Paule Kieny, director of WHO's Initiative for Vaccine Research.

-snip-

But if swine flu evolves into a more deadly strain, more shots may be needed to protect wider swathes of the population. Another possible complication is that the pandemic vaccine will be made using the strain available now; whether that will work if the virus mutates isn't certain.

At the moment, WHO has a bit of breathing space. The key component for the pandemic vaccine, the "seed stock" from the swine flu virus, will not be available for a few weeks.

-snip-

Recent work on H5N1 vaccines, the bird flu strain many thought would ignite the next pandemic, may also help. John Treanor, a vaccines expert at the University of Rochester said that adjuvants developed during H5N1 research may come in handy now.

He said public health officials were indeed facing a vaccine dilemma. "There is only a certain amount of capacity for vaccine manufacturing," he said. "One has to make some well-reasoned choices, sometimes based on incomplete information."