However, some experts have raised questions about biosafety and regulation of that type of work. In laboratory tests, a mixture of the AI-designed phages killed E.coli bacteria that had become resistant to naturally occurring phages. The viruses are already used in some parts of the world to treat persistent bacterial infections. In an accompanying article, Prof Tom Inglesby and Dr Moritz Hanke, of the Johns Hopkins Center for Health Security, said the work raised “urgent biosafety and biosecurity questions”. “The ability to compose viral genomes using generative AI now exists; the governance to safely steer it does not,” they wrote.