Here is a summary of the main findings of an international team of experts, led by the World Health Organization (WHO), which investigated the origins of the new coronvirus first identified in Wuhan, China, in late 2019. 

Reuters has seen the joint WHO-China report, which is due to be published on Tuesday at 1400 GMT. 

ON LIKELY SOURCES 

• direct zoonotic (animal-to-human) spillover is considered to be a possible-to-likely pathway; 

• introduction through an intermediate animal host is considered to be a likely to very likely pathway 

• introduction through cold/food chain products is considered a possible pathway 

• introduction through a laboratory incident was considered to be an extremely unlikely pathway 

ON THE ROLE OF THE HUANAN FARM MARKET IN WUHAN, CHINA 

Many early human cases were associated with the Huanan seafood market in Wuhan, which also sold wildlife, “but a similar number of cases were associated with other markets and some were not associated with any market”, the report said. 

“No firm conclusion therefore about the role of the Huanan market in the origin of the outbreak, or how the infection was introduced into the market, can currently be drawn.” 

ON WHETHER THE VIRUS WAS CIRCULATING OUTSIDE CHINA FIRST 

“The findings suggest that circulation of SARS-CoV-2 preceded the initial detection of cases by several weeks. Some of the suspected positive samples were detected even earlier than the first case in Wuhan, suggesting the possibility of missed circulation in other countries. 

So far, however, the quality of the studies is limited. Nonetheless, it is important to investigate these potential early events.”