A new French study has dismissed a cave in Mojiang County, southwest China's Yunnan Province as an origin of SARS-CoV-2, the virus that causes COVID-19.

The study, published online on the journal Environmental Research in late September, also rebuts lab-leak speculations that link the virus to several miners working in the county in 2012.

A retrospective analysis of their clinical reports showed that the miners had displayed symptoms very different from those shown by COVID-19 patients, Sputnik news agency reported.

"One must also wonder why a virus which killed more than 5 million and infected more than 200 million in 18 months did not cause any illness in 7 years from 2012 to 2019," the study read.

"Dismissing the Mojiang mine theory leaves the laboratory leak narrative without any scientific support thus making it simply an opinion-based narrative," it added.