Scientists who created easier-to-spread versions of the deadly bird flu said Friday they're temporarily halting more research, as international specialists debate what should happen next.
Researchers from leading flu laboratories around the world signed onto the voluntary moratorium, published Friday in the journals Science and Nature.
What the scientists called a "pause" comes amid fierce controversy over how to handle research that's high-risk but potentially could bring a big payoff. Two labs _ at Erasmus University in the Netherlands and the University of Wisconsin-Madison _ created the new viruses while studying how bird flu might mutate to become a bigger threat to people.
The U.S. government funded the work but last month urged the teams not to publicly reveal the exact formula so that would-be bioterrorists couldn't copy it. Critics also worried a lab accident might allow the strains to escape. The researchers reluctantly agreed not to publish all the details as long as the government set up a system to provide them to legitimate scientists who really need to know. The National Institutes of Health is creating such a system.
"We recognize that we and the rest of the scientific community need to clearly explain the benefits of this important research and the measures taken to minimize its possible risks," lead researchers Ron Fouchier of Erasmus and Yoshihiro Kawaoka of Wisconsin wrote Friday in the letter. They were joined by nearly three dozen other flu researchers.
They called for a public international meeting to debate how to learn from the work, safely. And they agreed to hold off on additional research with the existing lab-bred strains or that leads to any new ones for 60 days.
A U.S. official praised the development.
The moratorium "is a really good idea, because a lot of very important issues are at hand," said Dr. Anthony Fauci, director of the NIH's National Institute of Allergy and Infectious Diseases, who expects most flu researchers doing such work to sign on. "There aren't a lot of people who are doing that, I can assure you."
The U.S. also wants international input; researchers are talking with the World Health Organization.
Today, the so-called H5N1 bird flu only occasionally infects people, mostly those who have close contact with sick poultry. But when it does, it's highly lethal. The lab-bred H5N1 strains were a surprise because they showed it was easier than previously thought for the virus to mutate in a way that lets it spread easily between at least some mammals _ in this case, ferrets.