Retrospective Search for SARS-CoV-2 in Human Faecal Metagenomes

In the present study, we use ViromeScan to retrospectively search for SARS-CoV-2 genomic traces in human faecal viromes from publicly available metagenomes. Data from this preliminary, exploratory investigation provide evidence to support the presence of genomic traces of SARS-CoV-2 in the faecal virome of 6 out of 26 presumably asymptomatic Chinese, whose biological samples were collected before April 2019. By contrast, no SARS-CoV-2 was detected in the faecal viromes from 12 EU citizens, for whom faecal sampling dates back to March-April 2013 for Italians and before November 2019 for Spaniards. If confirmed on a larger population, our findings may reveal glimpses to support the recently advanced hypothesis suggesting the possible presence of a most recent common ancestor of SARS-CoV-2 in the human population before the outbreak of the current pandemic, possibly in an inactive non-virulent form, with important implications for the current unprecedented coordinated international effort to control the global spread of the virus.