The first Covid-19 infections in Italy date back to January, according to a scientific study presented on Friday, shedding new light on the origins of the outbreak in one of the world’s worst-affected countries.

Italy began testing people after diagnosing its first local patient on February 21 in Codogno, a small town in Lombardy region.

Cases and deaths immediately surged, with scientists soon suspecting that the virus had been around, unnoticed, for weeks.

Stefano Merler, of the Bruno Kessler Foundation, told a news conference with Italy’s top health authorities that his institute had looked at the first known cases and drawn clear conclusions from the subsequent pace of contagion. “We realised that there were a lot of infected people in Lombardy well before February 20, which means the epidemic had started much earlier,” he said

Italy is set to ease its coronavirus lockdown, the toughest and longest in Europe, over the next four weeks, the Corriere della Sera daily reported on Friday, although there was no official confirmation.