Tourists wearing masks are seen in Venice, Italy, Feb. 23, 2020. (Xinhua/Cheng Tingting)
A retest by Italian and Dutch researchers of pre-pandemic blood samples was found to have coronavirus-linked antibody IgM, Reuters reported recently.
The retest, carried out by researchers from the VisMederi laboratory at the University of Siena and their Dutch counterparts from the Erasmus University of Rotterdam, founded that the oldest sample with IgM dated back to Sept. 3, 2019, from Italy's northeastern region of Veneto, the media said in a report published Saturday, citing a paper published on July 14 that detailed the results from the retest.
The samples retested, which were originally collected from healthy volunteers in Italy who participated in a lung cancer screening trial before the pandemic started, were studied by VisMederi and the National Cancer Institute in Milan (INT) last year as they looked for coronavirus-linked antibodies.
In November 2020, VisMederi and the INT published their study, which showed that 11.6 percent of 959 healthy volunteers had developed COVID-19 antibodies well before February 2020 when the first official case was recorded in Italy, with four cases from the study dating to the first week of October 2019, which means those people had been infected in September 2019.
The study indicated that the virus could have circulated in Italy weeks before it was formally identified in China.
Citing Giovanni Apolone, INT scientific director, Reuters said 23 studies carried out in Europe and North America also "come to similar conclusions to the Italian research."