The new coronavirus may have been circulating in Italy since September 2019, months before the first official case was detected in the country, according to a new study from Italy. But public health experts say that more analysis is needed for that timeline to be confirmed.

https://www.livescience.com/coronavirus-circulating-italy-earlier-thought.html

The World Health Organization's China office first picked up the scent of a mysterious cluster of pneumonia cases in the city of Wuhan from local media statements on Dec. 31 and rang the alarm bells at the start of the new year, according to the WHO's timeline. Scientists later traced the first known case of COVID-19 in Wuhan back to Nov. 17, 2019, Live Science previously reported.

But the actual pandemic timeline — from the moment the virus hopped from animals to humans to when it first crossed international borders — remains murky. Italy, one of the worst-hit countries in Europe during the first wave of the virus, recorded its first local case on Feb. 20 in Lombardy, a region in northern Italy. That case suggested that the virus had been circulating in Italy since January of this year, according to the new study published on Nov. 11 in the Tumori Journal.

But some studies hinted at the possibility that the virus had been crossing borders long before then. One study found coronavirus RNA, or genetic material, in sewage samples taken on Dec. 18, 2019, in the cities of Milan and Turin. Another found that a patient in Paris who was treated in an intensive care unit in December 2019 had COVID-19, Live Science previously reported. Another analysis from Harvard University looked at satellite images and found that traffic at hospitals in Wuhan and online searches for COVID-19 symptoms were elevated compared with normal starting in the late summer and early fall of 2019. That suggested that the coronavirus may have been attacking us long before we knew its name.

To further clarify the early movements of the virus, a group of researchers analyzed blood samples from people in Italy who were enrolled in a prospective lung cancer screening trial between September 2019 and March 2020. They looked for antibodies specific to the receptor binding domain (RBD) — the dock on the coronavirus' spike protein that it uses to latch onto and invade human cells.