Just before Christmas, an obscure expert committee stopped science in its tracks - or at least one crucial research programme.
The committee is called the National Science Advisory Board for Biosecurity and it advises the US Government on science that might be used by terrorists or rogue governments.
It had concerns about two scientific papers that describe two man-made variants of the Bird Flu virus H5N1. Both variants were able to pass from mammal to mammal (in the case of these experiments, ferrets) through the air.
That was the important bit, because normally H5NI can't be passed on from person to person. Once you catch it, the virus is deadly (fatality rates are about 60 percent) but only about 600 people have ever caught it because in nature it isn't airborne.
The new virus appeared to combine lethality with infectivity - an ideal weapon for terrorists. That is why the US committee wanted to censor the two scientific reports to keep detailed information about how to make the "superbug" away from the wrong people.
Now the same committee has given the two research groups permission to go ahead and publish. The committee's chairman, Professor Paul Keim, told me the apparent reversal was because they had new "confidential" information that changed the committee's risk/benefit calculations.
That information, it seems, concerned the lethality of the man-made virus. In the experiments, the ferrets were infected with the virus by an aerosol, but they did not die. So the lethality of the new strains was, it seems, not as high as feared.
Sorry about all the "seems" and "appears" in that last paragraph, but I can't be more definite yet.
I asked Professor Ron Fouchier from the Erasmus Medical Centre in Rotterdam, one of the scientists involved, but he wouldn't give me any further details before his group's paper is published in the journal Science. Scientific journals almost always forbid scientists from talking about research until it is published and their colleagues can judge it.
All he could say was that the new man-made bird flu was a pretty lousy weapon for terrorists. So all the signs are that the "superbug" isn't a "superbug" at all.
But it will be important scientifically because with it researchers can build a vaccine or treatment against a superbug that emerges naturally. Such a superbug may combine lethality and infectivity, unlike the man-made version.
Some scientists believe that could happen at any time.