The numbers are modest but still alarming: 13 dead, 60 sick, from a new strain of bird flu in eastern China, according to the latest reports.
But even though the H7N9 virus so far has not spread outside of China, both national and international health officials worry that it may be just a matter of time before it does - and right now there's no vaccine to protect against the disease.
The New York Times reported on a new analysis by Chinese researchers that was published Thursday in the New England Journal of Medicine. It was accompanied by a commentary from American health officials, who said the disease "raises many urgent questions and global public health concerns."
The Chinese report detailed the deaths of three patients - an 87-year-old man, a 27-year-old man and a 35-year-old woman - who suffered severe complications from the virus, including respiratory failure, septic shock and multiple-organ failure. All three patients had preexisting medical conditions, and two of them had been exposed to poultry.
In a telephone news briefing for reporters, Nancy J. Cox, Ph.D., head of the influenza division of the Centers for Disease Control and Prevention (CDC), said H7N9 "causes quite severe illness in people who have been infected," although scientists are hoping to learn more about possible mild cases of the disease.
She also said the virus has genetic traits that help it infect mammals more easily than other bird flu strains. In addition, the virus doesn't seem to make birds sick, so its presence in flocks may go undiscovered until people start to get sick.
Researchers are not even sure exactly how many people have been infected. The most serious cases - where patients need to be hospitalized - are obvious, but if some people have mild symptoms or none at all, many cases could go undetected, the Times said.
Plus, Cox told reporters that it may be difficult to make a vaccine that's effective against the new strain. Clinical trials of vaccines produced to protect against other viruses in the H7 family have shown that the vaccines aren't very effective, even when people are given what would be considered very large doses, reported the Canadian Press.
Researchers, however, are hoping that new technology, allowing them to begin testing a "seed" strain of the virus made from genetic code, could help speed up the vaccine-making process, reported Reuters. Development of a new vaccine will still take months, but the new method could shave a few weeks off the process.
Although the virus apparently is still limited to China, Michael Shaw, Ph.D., a flu expert with the CDC, told the New York Times: "With air travel as extensive as it is now, if this is going to spread, it will spread pretty quickly. That's why we're relieved to see so far that it is localized, and not efficiently going from person to person."
Photo: Peter Cade/Getty Images
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