https://www.bbc.com/portuguese/internacional-55149801
A study published by the U.S. Centers for Disease Control and Prevention (CDC) adds another major question to the true origins of the covid-19 pandemic.

The official chronology begins on December 31, 2019, when health authorities in Wuhan, China, warned about a series of cases linked to a mysterious respiratory virus. The common denominator is a municipal market that sells live and dead wildlife.

Now, almost a year later, researchers with ties to the U.S. government have retroactively determined that 39 people from three states in the country had developed antibodies against the coronavirus two weeks before China's warning. The United States even officially identified its first case on January 21, 2020.

The study was based on blood samples donated between December 13, 2019, and January 17, 2020. The 7,389 samples analyzed were routinely collected from donations organized by the NGO Red Cross in nine U.S. states.