Did coronavirus start in China in August?
Coronavirus might have been spreading in China as early as August last year, according to US research based on satellite images of hospital travel patterns and search engine data.
But China has dismissed the Harvard Medical School, Massachusetts, study as "ridiculous".
The research is not peer-reviewed and has been published on the university's Digital Access to Scholarship at Harvard website.
The researchers used satellite imagery of hospital parking lots in Wuhan, where the disease was first identified in late 2019, and data for symptom-related queries on search engines for things such as "cough" and "diarrhoea".