Just how easy is it to make a deadly virus?

This disturbing question has been on the minds of many scientists recently, thanks to a pair of controversial experiments in which the H5N1 bird flu virus was transformed into mutant forms that spread among mammals.

After months of intense worldwide debate, a panel of scientists brought together by the World Health Organization recommended last week in favor of publishing the results. There is no word on exactly when those papers — withheld since last fall by the journals Nature and Science — will appear. But when they do, will it be possible for others to recreate the mutant virus? And if so, who might they be and how would they do it?

Scientists are sharply divided on those questions, as they are on the whole complex of issues surrounding the mutated virus known as mutH5N1.

On the question of who, while terrorists and cults have long been a concern in biosecurity circles, some scientists also fear that publication may allow curious amateurs to recreate the mutated virus — raising the risk of an accidental release.