Two members of WHO team blocked from entering China over failed coronavirus antibody test

An international team of 13 scientists was due to land in the central Chinese city of Wuhan, where cases of the coronavirus were first recorded in late 2019, on Thursday. But two members of that team remain in Singapore, the WHO said in a series of tweets, after they "tested positive for IgM antibodies."

IgM antibodies are among the earliest potential signs of a coronavirus infection, but could also appear in someone who has been vaccinated or previously infected (but is no longer a carrier) of the virus. False positives are also possible with such tests.