A Taiwanese researcher contracted SARS-CoV-2 while working with infected mice in a biosafety level 3 laboratory at the Genomics Research Center of Academia Sinica in Taipei, in the first known case of laboratory transmission of the virus. Authorities suspect the vaccinated researcher was infected via a mouse bite. The genomic sequence of the variant infecting the researcher matched that of the lab’s mice and not strains in the surrounding community, Taiwan’s Central Epidemic Command Center reported on 11 December. More than 800 potential contacts have tested negative, and Academia Sinica has promised an investigation and a review of the lab’s safety procedures. The incident is likely to bolster claims that a lab leak could have sparked the pandemic.