The World Health Organization (WHO) had recently declared that SARS-CoV-2 was the virus causing a worldwide pandemic (March 11, 2020) when several teams of researchers warned that it was already circulating at least a year earlier. This is the case of the Barcelona sewage study, which placed the origin at least in March 2019; the high impact of covid-19 in lung cancer patients which placed it in September 2019 in Italy, or a late 2019 study in the United States which stated that the coronavirus was already "widely disseminated" long before it was formally detected. A final study, from France, placed its origin in November 2019 but with a single case. All four papers were trying to find whether the virus had spread from the Chinese city of Wuhan or, instead, had emerged in different parts of the world. With the passage of time, none of the four papers holds up.