Researchers created a hybrid version of a bat coronavirus related to the virus that causes severe acute respiratory syndrome (SARS) that is capable of infecting human airway cells. The virus is not the first bat coronavirus known to be capable of binding to key receptors on human airway cells, but the results suggest that bat coronaviruses may be more of a danger to humans than previously believed. In 2014, the US asked researchers to suspend “gain-of-function” research making certain viruses more deadly or transmissible while the National Science Advisory Board for Biosecurity and the National Research Council assess the risks. The bat coronavirus research had already started and was allowed to continue when the moratorium was called. Critics of gain-of-function research worry that what we learn from it does not justify the risk of creating dangerous new viruses. Rutgers molecular biologist Richard Ebright told Nature that in his opinion “the only impact of this work is the creation, in a lab, of a new, non-natural risk”.