A scientist who worked on coronavirus projects funded by the U.S. is one of three Chinese researchers who became sick with an unspecified illness during the initial outbreak of Covid-19, according to current and former U.S. officials.

A scientist who worked on coronavirus projects funded by the U.S. is one of three Chinese researchers who became sick with an unspecified illness during the initial outbreak of Covid-19, according to current and former U.S. officials.