A simple math problem lies at the heart of a heated debate over whether scientists should be allowed to publish provocative research into the transmissibility of H5N1 flu. Assuming the avian virus could spread easily among people, just how deadly would an H5N1 pandemic be for humans?

Flu scientists tend to shy away from that question, suggesting that it is not possible to predict how lethal the virus would still be after undergoing the necessary changes to adapt to human physiology. But inevitably, people look for clues to what appears to be the best predictor of the virus's future path—its current behavior. And that appears downright terrifying: as many as 59 percent of people known to have contracted the virus have died from the infection.

More specifically, of the 584 people who have tested positive with what the World Health Organization (WHO) confirms is H5N1, 345 have died. (These numbers are current as of February 8, 2012.)

But what if H5N1 isn't as deadly as the official numbers suggest?

Indeed, two researchers have charged into the already fraught H5N1 publication controversy insisting the numbers are wrong, that the true mortality rate is likely to be much, much lower and that bad policy is being driven by the inflated figures.

Peter Palese, a noted influenza virologist at Mount Sinai School of Medicine in New York City, and Vincent Racaniello, a professor of microbiology at Columbia University Medical Center, also in New York City, are among a vocal group of scientists who vehemently oppose any decision to suppress the details of research conducted by Yoshihiro Kawaoka of the University of Wisconsin–Madison and Ron Fouchier of Erasmus Medical Center in the Netherlands.

Fouchier and Kawaoka had—at the request of the National Institutes of Health—figured out whether the H5N1 virus could become more transmissible in non-avian species. Their efforts reportedly revealed that just a few mutations were all that was needed to create a bird flu virus that is easily transmitted between ferrets. In addition, Fouchier said that his strain remained just as deadly to ferrets as it had been to birds, although Kawaoka later declared that his lab strain was not lethal.

Palese suggested in a perspective article co-authored by Taia Wang and published ahead of print on January 25, 2012 in Proceedings of the National Academy of Sciences that the case fatality rate of H5N1 human was almost certainly "orders of magnitude" too high.

Starting with the current 59 percent rate, if you start pushing the decimal point left, 59 becomes 5.9, which becomes 0.59 or even 0.059. Each adjustment of the decimal corresponds to an order of magnitude. (For comparison's sake, the mortality rate of current seasonal flu is less than 0.1 percent whereas researchers estimate that the mortality rate of the killer 1918 flu pandemic was around 2 percent.)

Racaniello, who did his thesis research under Palese, suggested on his popular Virology Blog in early January that the estimates of H5N1's killing potential were vastly overrated. Citing a recently published study that found what might be H5N1 antibodies in the blood of some villagers in Thailand, he mused that if 9 percent of rural Asians had antibodies to the virus, the perception of how dangerous H5N1 is would change dramatically.

In the flu world, few people would argue that Palese and Racaniello are wrong that the case/fatality rate is too high. It might be difficult, though, to find many who agreed with their conclusion on what that means about the virus.

6 Comments

1. 1. lamorpa 10:02 AM 2/14/12

   That pretty much covers it. It is definitely either more deadly, less deadly, or the same amount deadly. Of that I am 100% sure.

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2. 2. brandon 11:08 AM 2/14/12

   lamorpa,
   
   Terrific! In tune.

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3. 3. Christine Gorman in reply to lamorpa 11:31 AM 2/14/12

   And yet, policy is set on the basis of these facts. To censor research--or require the work to be conducted in BSL-4 instead of BSL-3 labs, which would result in fewer people doing the research, checking the results. That may be the right thing to do, but that is what is being debated.
   

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4. 4. Diesel67 10:05 PM 2/14/12

   We are not Communists. We do not censor the press, including the scientific press. That's why Western science is so robust.
   I could never understand mass hysteria surrounding the flu. It's ONLY THE FLU

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5. 5. Diesel67 10:13 PM 2/14/12

   for heaven's sake, a minor self-limiting viral illness. Those who die from it usually are old and debilitated, or have some pre-existing respiratory ailment (smoker's disease?). Of course most cases go unreported; what manly man is going to run to the doctor with THE FLU? We treat the symptoms with over-the-counter drugs, stay home from work or school so as not to infect our buddies, sleep as needed, give extra attention to hand washing and soon we're good as new. And when we get old and the flu progresses to pneumonia, let pneumonia carry us off before we lose control of our bodily functions and become dependent on others for the most basic daily care. I've seen what it's like to get old; thanks but no thanks.

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6. 6. Stagnaro 01:40 AM 2/15/12

   In my opinion, in science every discussion is worthy at the condition it is helpful to mankind. Let's consider, for instance, the discussion on CAD, type2 DM, and Cancer growing epidemics!

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