The new findings, conducted at the National Cancer Institute in Milan, suggest the pathogen may have been in Europe months earlier than it was first reported. The disease was first observed in Wuhan, China, in December, according to the World Health Organization.
In Italy, the first case of coronavirus was registered in Lombardy on February 21.
But scientists who carried out the study observed the pathogen in blood samples dating from September last year.
They said the research “may reshape the history of the pandemic”.
The study has been published in the scientific magazine Tumori Journal.
It analysed the blood samples of nearly 1,000 people who presented no symptoms.
The subjects were volunteers of a cancer study conducted from September 2019 until March 2020 in Milan.
The research revealed that more than 11 percent of the patients had formed coronavirus antibodies to the SARS-CoV-2 strain before February, including 14 percent from blood sampled obtained in September 2019.
The scientists wrote: “This study shows an unexpected very early circulation of SARS-CoV-2 among asymptomatic individuals in Italy several months before the first patient was identified.
“Finding SARS-CoV-2 antibodies in asymptomatic people before the COVID-19 outbreak in Italy may reshape the history of the pandemic.”
The study comes as it emerged a new coronavirus vaccine has shown nearly 95 percent protection against the virus.
Data suggests the jab, developed by US company Moderna, is even more effective than the Pfizer vaccine.
Pfizer became the first pharmaceutical firm to reveal the results of its coronavirus vaccine research on November 9.
The new developments brought hopes of a return to normal with Defence Secretary Ben Wallace saying the UK would get “on top” of the pandemic by “testing, tracing and then, hopefully sometime maybe before Christmas, vaccine”.
Mr Wallace said: “Certainly the military will have a role in the rollout of the vaccine.
“What exactly they’re going to be doing in that is what we’ve been working on for the last few weeks and months.”
Andrew Hill, senior visiting research fellow in the University of Liverpool’s department of pharmacology, said the Moderna vaccine had better prospects than the Pfizer jab.
He said: “This vaccine would be much easier to transport and administer than the one from Pfizer.
“Also, the preliminary evidence suggests that it can prevent severe COVID-19 disease.
“However, the Moderna vaccine is more expensive and there are fewer doses available in the next year. No vaccine company has enough supplies available to protect everyone in need.
“We will need all the available vaccines with over 90 percent efficacy to cover global demand.”