BEIJING — No infections caused by convalescent COVID-19 patients have been detected so far, Guo Yanhong, an official with the National Health Commission, said on Feb 28.

Guo noted at a press conference in Beijing that some provincial-level regions had reported positive nucleic acid test results of some recovered patients, who had earlier been discharged from hospitals, in subsequent visits required by the commission.

No infected cases caused by this group of people had been found, Guo said, adding that some of them had later tested negative for COVID-19.

The commission had paid great attention to related issues by organizing experts for research and would reinforce the continuous monitoring of convalescent patients, Guo said.

She added that the novel coronavirus demands further understanding of its pathogenesis, the overall picture of the disease and the characteristics of the disease's course.