Where did COVID come from? Five mysteries that remain

Following a month-long fact-finding mission in China, a World Health Organization (WHO) team investigating the origins of the COVID-19 pandemic concluded that the virus probably originated in bats and passed to people through an intermediate animal. But fundamental questions remain about when, where and how SARS-CoV-2 first infected people. As the international WHO team finalizes a report of its findings, which is expected next week, Nature speaks to four of the investigators about what they still want to know.