The total number and mass of SARS-CoV-2 virions

Quantitatively describing the time course of the severe acute respiratory syndrome coronavirus 2 (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 typical viral load of SARS-CoV-2 in bodily fluids and host tissues 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) to 10(11) virions during peak infection, with a total mass in the range of 1 mu g to 100 mu g, which curiously implies that all SARS-CoV-2 virions currently circulating within human hosts have a collective mass of only 0.1 kg to 10 kg. We combine our estimates with the available literature on host immune response and viral mutation rates to demonstrate how antibodies markedly outnumber the spike proteins, and the genetic diversity of virions in an infected host covers all possible single nucleotide substitutions.

Automated summary

Each infected person carries 10^9 to 10^11 SARS-CoV-2 virions during peak infection, with a total mass in the range of 1-100 micrograms. The study shows that antibodies in infected hosts significantly outnumber spike proteins, and the genetic diversity of virions covers all possible single nucleotide substitutions.