The bird flu virus H5N1, in gold, is seen among cells known as MDCK, in green,… (C. Goldsmith / CDC )
Bird flu researchers said Wednesday that they would end a self-imposed moratorium on controversial experiments to determine how the deadly H5N1 virus might mutate and gain the ability to spread easily among humans.
In a statement published online by the journals Science and Nature, 40 scientists said they were poised to resume their investigations — but only in countries that have established clear rules for conducting the research safely. The U.S., which is the largest funder of influenza research, is not yet among those nations.
"We want to resume virus transmission studies because we believe this research is important to pandemic preparedness," said University of Wisconsin virologist Yoshihiro Kawaoka, one of the scientists whose work prompted biosecurity experts to call for new restrictions on flu research.
There have been only 610 confirmed human cases of bird flu since 2003, but 59% of those people have died. In nature, the virus has very limited ability to spread directly from person to person. Scientists fear that just a few key genetic mutations could change that, creating the potential for a dangerous flu pandemic.
Kawaoka and Ron Fouchier, a virologist at the Erasmus Medical Center in the Netherlands, have been studying some of the mutations that could make bird flu more transmissible in mammals. In separate experiments, both men developed strains of H5N1 that could pass between ferrets in the tiny droplets expelled by coughs and sneezes. Ferrets are used in influenza studies because they respond to flu much as people do.
Kawaoka and Fouchier were on the verge of publishing their study results until late 2011, when their work caught the attention of a government advisory panel that assesses potential risks of biological research.
Worried that the flu strains could prove dangerous if they escaped the lab, the U.S. National Science Advisory Board for Biosecurity asked the scientists — and editors at Science and Nature, where their work had been accepted for publication — to redact portions of the research. It was an unprecedented move that many scientists saw as a threat to academic freedom and debate.
The researchers announced on Jan. 20, 2012, that they would suspend their work for 60 days to allow time for discussion of the risks and benefits of the research. U.S. and foreign officials, the World Health Organization and scientific groups met several times to delineate policies for continuing the research safely, including biosecurity requirements.
In the end, the moratorium lasted for just over a year. Both Kawaoka and Fouchier signed the statement published Wednesday.
In a conference call, the researchers said that continuing the study of H5N1 under appropriate laboratory conditions was crucial, because it could help them better understand how the virus becomes airborne — and let public health officials get ahead of potentially dangerous mutations that might arise in birds and mammals, perhaps by culling infected animals or using the information to develop vaccines.
"Once these mutations start popping up in nature, countries should eradicate it aggressively," Fouchier said.
Kawaoka emphasized that only nine changes in H5N1 made the virus transmissible in Fouchier's experiment.
"Nine is almost none," he said, because flu mutates very easily. "The risk exists in nature already. Not doing the research is really putting us in danger."
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which funded Fouchier's and Kawaoka's experiments, agreed that H5N1 transmission research should resume. He said that a framework to help the U.S. National Institutes of Health decide which H5N1 transmission studies should receive funding in the future should be ready "within a relatively short period of time — I hope measured in weeks."
Until then, Kawaoka will have to continue waiting. Fouchier will be able to resume some of his ferret research shortly using Dutch funding.
Kawaoka and Fouchier said they believed research in other European countries, as well as in China and Canada, could now move ahead, and that Japan, like the U.S., still had not released guidelines.
Michael Osterholm, an infectious disease researcher at the University of Minnesota and a member of the U.S. biosecurity panel, said he was still worried that publishing the results of H5N1 experiments could give scientists who don't have appropriate facilities and expertise a "blueprint" for doing dangerous research.
"We may tell people not to do it, but if they go ahead and the virus escapes, it's done," he said. "You cannot contain influenza."
Osterholm suggested that a better policy would be to continue the research, but to share findings with a limited audience.
Fauci said that the NIH did not fund classified research, choosing instead to vet grants carefully in advance and monitor operations strictly.