WE MAY never know for certain how the SARS-CoV-2 virus jumped from another animal to a human before upending our world. Getting a convincing answer will take some time, judging by the first results from a World Health Organization investigation into the origins of the new coronavirus. The WHO team served up more questions than answers at a press conference last month, ruling out a lab origin, but calling for more research into the possibility that it was carried via frozen food.

Most virologists regard that as unlikely . The most plausible route seems to …