A bid from some quarters in the U.S. to resolve the ongoing controversy over two unpublished bird flu studies will begin to play out over the next two days as government biosecurity advisers reconvene to reconsider the issue.

The National Science Advisory Board for Biosecurity will meet Thursday and Friday in Washington, D.C., to go over revised versions of the two studies and hear about the work from their principal authors, noted flu virologists Ron Fouchier of Erasmus Medical Centre in Rotterdam, the Netherlands, and Yoshihiro Kawaoka of the University of Wisconsin-Madison.

Then the group will have to decide whether to advise the U.S. government to withdraw its objection to full publication of the papers, continue to press for publication in abbreviated form or suggest the studies should not be published at all.

People involved in the process don't want to prejudge what the group's decision might be. But some parties to the controversy were at pains this week to point out that the 23-member NSABB can only advise the U.S. government.

The government is not bound to accept the panel's advice and, even if it does, it can only ask the journals that want to publish the work to withhold parts or all of the studies.

And regardless of what the U.S. government decides, the journals, Science and Nature, could still publish the studies, Fouchier said earlier this week during a panel discussion at a conference in Ireland.

"This is advisory. This is purely advisory," Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, said of the NSABB process. Fauci's institute is part of the U.S. National Institutes of Health.

Fauci said the NSABB will convey its decision to the NIH, which will pass it to Kathleen Sebelius, secretary of health and human services. Fauci admitted that as it passes on the recommendation, the NIH can also weigh in, saying it agrees or disagrees with the advice of the biosecurity group.

The NSABB touched off this controversy late last fall when it recommended that the U.S. government ask the journals to withhold sections of studies Fouchier and Kawaoka planned to publish in Science and Nature respectively. The studies show how the two teams mutated H5N1 flu viruses to the point where they spread through the air from mammal to mammal, in this case ferrets.

In the wild the worrisome H5N1 virus does not transmit this way. When mammals -- including people -- are infected, chains of transmission die out quickly because the virus is not adapted to infect human airways. Kawaoka and Fouchier's work was designed to see if the viruses could adapt to easy spread among mammals.

The NSABB recommended that the details of how Fouchier and Kawaoka performed their experiments should be withheld, to prevent others from trying to replicate the work for nefarious intentions or simply for the challenge.

But a meeting, held by the World Health Organization in mid-February, concluded it would be impractical to try to hold back parts of the studies.

If parts of the studies are withheld for security reasons, export regulations designed to prevent the development and proliferation of weapons kick into play. Those laws would make sharing the information across borders -- potentially even from a U.S.-based researcher to his U.K.-based publisher -- a logistical nightmare.

And sharing the findings with other researchers or public health agencies in H5N1-infected countries could take years, the meeting concluded.

"It was very hard to see what that mechanism would be," said Dr. Keiji Fukuda, the WHO's point person on this issue and the chair of the February meeting.

"There are definitely a lot of pretty difficult problems that came up. And so while I won't say that it's impossible -- you know, enough people given enough time can probably figure out some ways to do virtually anything -- in the here and now I certainly haven't heard of any very practical ways to do that."

Fukuda, assistant director-general for health security and environment, also stressed that the NSABB is an advisory body, and it will be up to the U.S. government to decide what to do about any recommendation that comes from the group.

At the Dublin conference, Fouchier predicted the journals will publish the papers, within weeks. And he expressed the hope that he'll be able to resume his work on H5N1 within two weeks.

The small international pool of influenza virologists who do the type of work Fouchier does agreed in January to a two-month moratorium on H5N1 transmission studies. It ended, in theory, last week, but the group agreed to extend it for an unspecified time in the hopes it would help to resolve the controversy.

Fukuda said he wasn't sure what the journals will do if the U.S. government continues to ask that the details of the work be withheld from publication, but he believes they don't want to touch off more controversy.

"I think the journals are in a tough position," he said.

"It's clear that the journals would like to go ahead to publish. But it's also clear that the journals themselves recognize the difficulties and the issues ... and that they understand that it's a fairly vigorous, fairly delicate discussion which is going on about how do you weigh dual use (research) concerns versus research priorities?"