The US government has lifted a three-year ban on making lethal viruses in the lab, saying the potential benefits of disease preparedness outweigh the risks. Labs will now be able to manufacture strains of influenza, Sars and Middle East Respiratory Syndrome (Mers). The ban was imposed following safety breaches at federal institutions involving anthrax and avian flu. Now a scientific review panel will have to green-light each research proposal. It will only be allowed to go ahead if the panel determines there is no safer way to conduct the research and that the benefits it will provide justify the risk. Critics say such gain-of-function" research still risks creating an accidental pandemic. The ban was imposed in 2014 after embarrassing safety lapses including ... dozens of workers at the US Centers for Disease Control and Prevention (CDC) being exposed to anthrax bacteria, [and] long forgotten vials of smallpox left in a cardboard box being discovered at a research centre near Washington. In addition, there was concern that research into transmissible pathogens, which is published, could be used to deliberately engineer a mutant virus. Now, the US National Institutes of Health says it is time to lift the ban on funding such research.