Using serum samples routinely collected in 9144 adults from a French general population-based cohort, we identified 353 participants with a positive anti-SARS-CoV-2 IgG test, among whom 13 were sampled between November 2019 and January 2020 and were confirmed by neutralizing antibodies testing. This suggests early circulation of SARS-CoV-2 in Europe.
A recent investigation of the presence of SARS-CoV-2 antibodies in 959 adults participating to a trial in Italy with blood samples collected between September 2019 to February 2020 identified 111 (11.6%) samples with a positive receptor-binding protein specific enzyme-linked immunosorbent assay (ELISA), among which 4 samples collected in October, 1 in November and 1 in February were also positive in a qualitative microneutralization assay [4]. This indicates that SARS-CoV-2 could have been present in Italy since the beginning of autumn 2019.
