News of the COVID-19 virus became widespread in December 2019, as the then-unknown virus rapidly spread through the Chinese city of Wuhan. A new study by the National Cancer Institute, however, has found that the virus may have been present in Milan, Italy as early as September 2019.
This may mean that the virus could have been in the Italian city five months before its first patient was officially detected, and three months before the outbreak in Wuhan.
In a study published to Tumori Journal on November 11, Italian researchers reported that 12% of 959 healthy volunteers enrolled in a lung cancer screening trial between September 2019 and March 2020 developed coronavirus antibodies long before February 21, when the country’s first case was identified.
According to Giovanni Apolone, a co-author of the study, four cases dated back to early October 2019, which meant the healthy volunteers would have been infected in September.
“This is the main finding: people with no symptoms not only were positive after the serological tests but had also antibodies able to kill the virus,” he said. “It means that the new coronavirus can circulate among the population for long and with a low rate of lethality not because it is disappearing but only to surge again.”
“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, and clarifies the onset and spread of the coronavirus disease 2019 (COVID-19) pandemic,” reads the study. “Finding SARS-CoV-2 antibodies in asymptomatic people before the COVID-19 outbreak in Italy may reshape the history of pandemic.”
In March, Italian researchers also reported a higher-than-average number of severe pneumonia cases and flu outside Milan in the last quarter of 2019. This has now been taken as an early sign that the virus could have been around well before the “outbreak”.