Figuring out what an acceptable path towards that end might be will likely occupy considerable time and brain power as many of the researchers capable of doing this work meet in New York next week.
Several months ago many expected the research moratorium would have been lifted by now. But it is becoming clear to the flu community that getting back to business as usual may not be an easy or quick task.
"I very much hope ... that no decision is made at that meeting," microbiologist David Relman says of the annual gathering of the Centers of Excellence for Influenza Research and Surveillance.
"I think that would be a terrible mistake for this particular sequestered private group to make a declaration and decide on their own that the moratorium has been lifted. I think that would be a terrible thing."
The group goes by the acronym CEIRS, pronounced like the department store Sears. Its annual three-day get-together begins work Monday in New York City.
Relman is not an influenza researcher and he won't be at the meeting. But he will be watching for developments. He is a member of the National Science Advisory Board for Biosecurity, a group that advises the U.S. government on so-called dual-use research — legitimate science that could pose a security threat in the wrong or in sloppy hands.
Last fall, the group touched off a fire storm by urging that two studies detailing how H5N1 viruses could evolve to transmit among mammals — they currently do not — should not be published in full.
After months of public and private wrangling, the group relented, though some members continue to question whether details of the research should be in the public domain. Relman is among them.
He also worries about a resumption of this type of research, which many flu experts insist is crucial but which some scientists suggest is tempting disaster. If one of these potentially transmissible viruses were to escape from a high containment lab, critics argue, the world could face a pandemic with a virus which so far seems unusually lethal for humans.
"I think the most important point is that this can't be a self-proclaimed decision or assessment by a very narrow group of people behind closed doors. This has to be an open process," insists Relman, who teaches at Stanford University in California.
"It really has to involve all of the other sectors of the scientific research community and all of the other kinds of communities that have a vested interest, including policy makers, including the national security community, including the general public."
When the scientists announced the moratorium in late January, it was a good faith gesture meant to help pave the way to publication of the two studies. The moratorium was supposed to last 60 days, until the end of March.
But the first of the contested studies — by Yoshihiro Kawaoka of the University of Wisconsin-Madison — wasn't published until May. The second and more contentious, led by Ron Fouchier of Erasmus Medical Centre in Rotterdam, the Netherlands, wasn't published until late June.
At that time, Fouchier expressed eagerness to resume H5N1 transmissibility studies. He said he hoped the moratorium would be lifted in a co-ordinated manner, but wasn't sure about waiting, if concerns in the United States meant the delay dragged on.
"If the U.S. is going to take a year from now, I don't think it's wise that the whole world is waiting for what the U.S. will be doing," he said at the time. Fouchier did not respond to a request for an interview for this article.
At the time Fouchier's paper was published, the head of the U.S. National Institute of Allergy and Infectious Diseases, Dr. Anthony Fauci, said he wanted to talk with flu researchers at the CEIRS meeting about the future of the moratorium.
Fauci's institute funds the CEIRS network. Kawaoka and Fouchier — and many other top flight flu researchers in the U.S. and abroad — get funding through the network.
Adolfo Garcia-Sastre heads one of the CEIRS centres. A virologist at Mount Sinai Hospital in Manhattan, he doesn't expect a decision to lift the moratorium will come out of this meeting.
"A decision about lifting the moratorium? No. A decision about what it requires to lift the moratorium? Maybe," Garcia-Sastre says.
He notes there are policy pronouncements that must take place before H5N1 transmission studies funded by the U.S. government can resume. Among them: a government panel must rule on what level of biosafety and biosecurity this type of flu research requires.
Currently most scientists who do this research work in laboratories with Level 3-enhanced containment. (Canada announced earlier this year that any scientists in this country who want to do this type of research would need to work in the highest containment labs, Level 4.)
It's believed the U.S. committee reached a decision weeks ago. But it has not been announced and there is no explanation for the delay.
There are questions in some quarters whether an eagerness to keep this issue from becoming a a political hot potato in the lead up to the U.S. elections may mean nothing major on this front will happen before November.
In the months after the controversy first emerged, scientists from other specialties questioned whether these transmission studies ought to have been conducted in the first place. Why set out to make a more dangerous bird flu virus, they argued.
Even some flu experts worry about the work.
"Where's this going to take us?" asks Dr. Ilaria Capua, an outspoken Italian researcher who runs an avian influenza reference laboratory for the Food and Agriculture Organization in Padua.
"When are we going to have another moratorium because somebody else comes up with a virus that we don't want to have in many labs around the world?"
She is not alone in worrying about what will happen when the next study is sent to the biosecurity advisory board to be vetted. There are believed to be a number of potentially contentious ones being written or in the publication pipeline, based on data generated before the moratorium was put in place.
Relman says flu scientists should understand that the NSABB didn't give carte blanche to all this type of research when it cleared Kawaoka's and Fouchier's papers.
Capua says it's unfortunate that in the time since the moratorium was announced, there wasn't a greater effort to resolve questions like whether there is a line that ought to be drawn and if so, where it is.
"It seems to me to be that this is nobody's baby. And nobody wants to say: OK, we need to start talking about it," she says.
But Derek Smith, a professor of infectious diseases informatics at Cambridge University, says there is a debate going on.
"There is a process that is going on," says Smith. "Some of it has looked a little bit ugly. But it does make sense for a process to go on. Serious people are thinking about this and have thought about it."
Smith was the senior author of a recent study showing some H5N1 viruses in the wild carry some of the mutations needed to become more transmissible to mammals.
"It's clear the virus isn't waiting," he says. "It's also clear that the work has to be done very carefully. And that there is a balance to be drawn."