If all the SARS-CoV-2 coronaviruses circulating in the world were collected in one place, then their total mass would be from 0.1 to 100 kilograms. This is the conclusion reached by scientists at the Weizmann Research Institute in Israel. This is reported in an article published in the journal Proceedings of the National Academy of Sciences. Briefly about the scientific work is the publication Science Alert.
First, experts calculated how many viruses each infected person carries. This is a rough estimate, since different people will have different viral loads at the peak of infection, it depends on the characteristics of the organism. The researchers used data from previous measurements of the number of viral particles in rhesus monkeys during the peak of infection in various organs (lungs, tonsils, lymph nodes and the digestive system), extrapolating to the mass of human tissue.
The number of viruses is 10-100 billion per infected person, which corresponds to 1-10 micrograms. Since the total number of infected people who have not yet recovered ranged from one million to 10 million at any given time, the total mass of viruses lies somewhere between the mass of an apple and the mass of a child. The mass of one viral particle is approximately one femtogram (10 to the minus 15th power of a gram).
In addition, scientists have calculated that during infection of one host, the virus accumulates from 0.1 to 1 mutations throughout the genome. This characteristic was obtained on the basis of data on the frequency of nucleotide substitutions, the number of nucleotides in the SARS-CoV-2 genome, as well as the number of viral replications within the body. Thus, a virus transmitted from person to person accumulates about three mutations per month.
The authors of the work compare the effect produced by a small mass of the pathogen with the explosion of a nuclear bomb, which contains less than one hundred kilograms of fissile material, but leads to colossal destruction. According to Johns Hopkins University, the virus has already infected over 137 million people and killed over 3.7 million.