Monday, November 29, 2004

Epidemic! Epidemic!

WHO aide warns of avian flu pandemic

Problem is, I burnt out on SARS last year. I still don't understand why all hell didn't break loose then. My best guess is that there were multiple strains of SARS circulating simultaneously, and an innocuous one spread faster -- immunizing the susceptibles in advance of the killer strain.

So, now there are dire warnings on Avian Flu. After anthrax (dire warnings, then nothing -- yeah, I know it's not contagious, but that wasn't what the warnings were about) and SARS, are we able to take this one seriously?

The infection estimates are 1/3 of the world with 2-100 million deaths. If that happened the economic, social, and military consequences would be enormous.

On the other hand the SARS tale is not irrelevant. Avian flu has a 70% mortality rate in the infected, but SARS was about 15-50% depending on the population studied. Those are order of magnitude comparable, but those numbers can be exceedingly misleading for many reasons.

We ought to do a lot more with public health than we do, especially in the "red states" that don't fund public health at all. Other than that ...?
A global pandemic of avian influenza is "very, very likely" and could kill tens of millions of people around the world, a top World Health Organization official said Monday.

Governments should be prepared to close schools, office buildings and factories in case of a pandemic, and should work out emergency staffing to prevent a breakdown in basic public services like electricity and transport, said Dr. Shigeru Omi, the organization's regional director for Asia and the Pacific.

Such arrangements may be needed if the disease infects 25 to 30 percent of the world's population, Omi said. That is the WHO's estimate for what could happen if the disease - currently found mainly in chickens, ducks and other birds - develops the ability to spread easily from person to person.

Deaths associated with the rapid spread of a new form of influenza would be high, he said.

"We are talking at least 2 to 7 million, maybe more - 20 million or 50 million, or in the worst case, 100" million, he said.

While many influenza experts have discussed similar figures privately, Omi's remarks represented the first time a top public health official had given such an estimate in public. But his remarks on the likelihood that the disease would start spreading easily went beyond the assessment of many scientists, who say that too little is known about the virus to gauge the odds that it will become readily transmissible.

Dr. Malik Peiris, a top influenza researcher at Hong Kong University, said that Omi's range of potential fatalities was realistic and consistent with current research into the A(H5N1) avian influenza virus. The biggest questions, he said, were whether the disease would develop the ability to spread easily from person to person and, if it did, whether it would retain its current deadliness.

... Omi and Peiris each pointed out that the high death rate recorded so far might be overstated, because people with less severe cases of the disease might not be diagnosed as having it.

Peiris also pointed out that one likely way for the disease to acquire the ability to pass easily from person to person - the acquisition of human influenza genetic material by the virus - could also reduce the death rate to the range described by Omi.

"If the virus reassorts and picks up human influenza genes then it's quite possible the severity could be limited," Peiris said.

The WHO, a Geneva-based UN agency, has reported 44 confirmed human cases of A(H5N1), 32 of whom have died, a 72.7 percent rate. The WHO has identified only one case of probable human-to-human transmission - a mother who cradled her dying daughter all night - while the rest of the cases appeared to have been acquired directly from animals.

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