The total number and mass of SARS-CoV-2 virions in an infected person

Sender, Ron; Bar-On, Yinon M.; Flamholz, Avi; Gleizer, Shmuel; Bernsthein, Biana; Phillips, Rob; Milo, Ron

Quantitatively describing the time course of the SARS-CoV-2 infection within an infected individual is important for understanding the current global pandemic and possible ways to combat it. Here we integrate the best current knowledge about the abundance of potential SARS-CoV-2 host cells and typical concentrations of virions in bodily fluids to estimate the total number and mass of SARS-CoV-2 virions in an infected person. We estimate that each infected person carries 10(9)-10(11) virions during peak infection, with a total mass of about 1 μg-0.1 mg, which curiously implies that all SARS-CoV-2 virions currently in the world have a mass of only 0.1-1 kg. Knowledge of the absolute number of virions in an infected individual can put into perspective parameters of the immune system response, minimal infectious doses and limits of detection in testing.