Two separate research teams were forced to temporarily halt their studies which showed how to produce a version of the highly pathogenic H5N1 avian flu virus that is easily transmissible in mammals. The findings led a U.S. government agency to request that only the results be published, leaving out the methods.
The H5N1 virus, although easily transmitted among birds, is not very contagious among humans. But the virus is very dangerous when do humans catch it –  343 of the infected people have died of the disease.
As a result, the National Science Advisory Board for Biosecurity (part of the National Institutes of Health) requested that the methods used in the experiments not be published.