The National Institutes of Health (NIH) took samples from Americans and found seven people in Illinois, Massachusetts, Mississippi, Pennsylvania and Wisconsin had Covid before the first case was detected.
The US reported its first Covid cases on January 21 last year.
NIH data suggested Covid could have been present in the US as early as December 24 2019, with the cases said to be far away from expected points of entry.
Zhao Lijian, spokesperson of China’s Ministry of Foreign Affairs, cited the study and claimed it is supported by similar evidence seen in international scientific journals.
He then added: “It is obvious that the outbreak had multiple origins.”
Mr Zhao also citied chief Swedish epidemiologists who have suggested the virus was present in Sweden as early as November.