Virus may have been in Italy in October 2019

Retesting of blood samples has shown that it is possible Covid-19 was circulating in Italy in October 2019.

The World Health Organisation asked for further clarification after researchers in Milan claimed samples from cancer patients showed Covid19 may have been circulating for several months in Italy even before the first cases were reported in China in November 2019.

Researchers tested blood samples from 959 individuals who had been screened for lung cancer and found that 111 tested positive for antibodies against Covid-19. The earliest sample showing one type of antibody — IgM — was collected in October 2019, the researchers said.

At the request of the WHO, 29 original and 29 control samples were sent to VisMederi laboratory in Siena, Italy, and Erasmus University in the Netherlands. Three samples were found by both Erasmus and VisMederi to be positive for IgM, the researchers said.

However, Erasmus found that none of the samples contained high enough levels of each of the three types of antibodies that it needs to consider proof of infection.

Marion Koopmans, professor of virology at Erasmus, said it was “not impossible” that the patients had been infected with Covid-19. “Just that you would like to see other pieces of evidence.”