Using mathematical models, a quartet of Chinese scientists has argued that the first case of Covid-19 appeared between April and November 2019 in the northeastern US, long before the outbreak in Wuhan, China.

“The calculation results show that the COVID-19 epidemic in the United States has a high probability of beginning to spread around September 2019,” says the 14-page paper published on Wednesday at ChinaXiv, a repository operated by the National Science Library of the Chinese Academy of Sciences.

The paper was authored by Zhouwang Yang, Yunhe Hu, and Zhiwei Ding from the University of Science and Technology of China, and corresponding author Tiande Guo of the University of Chinese Academy of Sciences. (RT)