The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has hit health-care systems and societies in an unprecedented manner. In 1981, the first cases of AIDS were reported and wide diagnostic ...

A relationship between the infecting dose and the risk of disease severity has not been demonstrated for SARS-CoV-2 infection. Here, we report three clusters of individuals that were potentially exposed to distinct inoculum ...