EVIDENCE WORLDWIDE

Not merely in the United States, more researches have added to growing evidence that COVID-19 was circulating outside of China earlier than previously thought.

In Spain, researchers at the University of Barcelona, one of the European country's most prestigious universities, had detected the presence of the virus genome in waste water samples collected on March 12, 2019, the university said in a statement in June.

These results "suggest the infection was present before knowing about any case of COVID-19 in any part of the world," the statement said.

"Although COVID-19 is a respiratory disease, researchers proved there are large quantities of the coronavirus genome in the excrements that reach waste waters. This situation made the waste water-based epidemiology a potential tool for early detection of the circulation of the virus among the population," the statement said.

In France, scientists found a man was infected with COVID-19 in December last year, roughly a month before the country confirmed its first cases.

Citing a doctor at Avicenne and Jean-Verdier hospitals near Paris, BBC News reported that the patient "must have been infected between Dec 14 and 22, as coronavirus symptoms take between five and 14 days to appear."

Meanwhile, in Italy, a recent research by the National Cancer Institute in Milan showed that 11.6 percent of the 959 healthy volunteers who participated in a lung cancer screening trial between Sept 2019 to March 2020 had developed COVID-19 antibodies well before February when the first official case was recorded in the country, with four cases from the study dated to the first week in October last year, which means those people had been infected in September.