An outbreak of avian flu could attack societies with the ferocity of a global war, bringing widespread deaths and illness, and severe disruptions of the economy and social networks.
That is the fear expressed by many of the leaders at a meeting of more than 100 countries here at World Health Organization Headquarters in Geneva.
And just as they would respond to the threat of war, the leaders say individual nations and international agencies should take every action to try to prevent the disaster and hope it does not happen, but must prepare as best as possible in case it does.
Why the fear?
The current outbreak of the H5N1 virus in birds, now in its second year, is unprecedented. Hundreds of millions of birds have either been killed directly by the virus or been culled in efforts to contain the outbreaks. That alone has economically devastated farmers and those who depend on them in many Asian nations.
The existence of the virus in migrating birds indicates it will persist for the foreseeable future, as it spreads throughout Asia, recently to Europe and soon to the Middle East and Africa.
But of course it is the occasional human case that is causing the great concern. Among the approximately 120 people infected so far, the death rate has been 50 percent.
No one knows what the death rate would be if the virus mutates so it can pass easily from person to person – or whether such a mutation will ever take place. But it is worth noting that the death rate in the 1918 pandemic that killed 20-50 million people in the world was three percent.
And H5N1 is so different from any influenza virus that has previously infected humans that no one would have natural immunity if the virus were able to easily infect people.
Need for more vaccines
Vaccines to prevent an infection will not be an option for this year in the United States and Europe and for many more years, if ever, in the rest of the world.
The entire world capacity for producing influenza vaccine is now 300 million doses a year, just enough for the U.S. alone. And it takes at least six months from the identification of a virus until the appropriate vaccine is produced.
There is much talk of expanding vaccine manufacturing but it will not happen quickly. The anti-viral drugs Tamiflu and Relenza are getting a lot of attention.
Many European nations have purchased enough to treat 20 percent or more of their populations. Japan has enough to treat almost all its citizens. The U.S. has far less, as do most countries.
The World Health Organization announced today that Roche, the pharmaceutical company which makes Tamiflu, will be able to produce 115 million additional doses next year and 300 million in 2007. But many experts caution that the evidence that the drugs could contain or mitigate a pandemic outbreak is weak.
What can be done now?
The consensus that has emerged at the WHO meeting here in Geneva is that the best hope lies with earliest identification of bird and human cases and attempts to contain them whenever they break out.
To make that a possibility richer nations need to support efforts in poor countries. For example a chicken farmer must be adequately compensated for any animals that are killed so he will not hide cases. Every nation needs to have the laboratory facility to make at least a preliminary identification of H5N1.
But the challenge is enormous. If a large bird flu outbreak were confirmed in humans, panic would ensue. Everyone with a respiratory infection would be a suspected case.
Nations would almost certainly slam their borders shut. But the experts say the only hope of mitigating this potential catastrophe is to plan for it now.