Coronavirus quickly spread around the world starting late last year: CNN

[Photo: Screenshot of CNN's report]

A new genetic analysis of the virus that causes Covid-19 taken from more than 7,600 patients around the world shows it has been circulating in people since late last year, and must have spread extremely quickly after the first infection, reported CNN.

Genetics researcher Francois Balloux of the University College London Genetics Institute told CNN that he and colleagues pulled viral sequences from a giant global database that scientists around the world are using to share data. They looked at samples taken at different times and from different places, and said they indicate that the virus first started infecting people at the end of last year.

"This rules out any scenario that assumes SARSCoV-2 may have been in circulation long before it was identified, and hence have already infected large proportions of the population," Balloux's team wrote in their report, published in the journal Infection, Genetics and Evolution. At the most, 10% of the global population has been exposed to the virus, Balloux estimated.

They also found genetic evidence that supports suspicions the virus was infecting people in Europe, the US and elsewhere weeks or even months before the first official cases were reported in January and February. It will be impossible to find the "first" patient in any country, Balloux said.

"All these ideas about trying to find a Patient Zero are pointless because there are so many patient zeros," he said.