Sars-Cov-2 Transmission Routes And Implications For Self- And Non-Self-Protection

The global spread of the coronavirus SARS-CoV-2 has massively impacted health, economic, and social systems. Although effective vaccines are now available, it is likely that this pathogen will become endemic and stay with us for years. In order to most effectively protect others and oneself from SARS-CoV-2 infection, an understanding of how SARS-CoV-2 is transmitted is of utmost importance. In this review paper, we explain transmission routes with an eye towards protecting others and oneself. We also address characteristics of SARS-CoV-2 transmission in the community. This work will help to clarify the following questions based on the available literature: When and for how long is an infected person contagious? How is the virus excreted? How is the virus taken up? How does the virus spread in society? Human-to-human transmission of SARS-CoV-2 is strongly determined by pathogen molecular characteristics as well as the kinetics of replication, shedding, and infection. SARS-CoV-2 is transmitted primarily via human aerosols, which infected persons can excrete even if symptoms of the disease are not (yet) present. Most infected people cause only a few secondary cases, whereas a few cases (so-called super-spreaders) cause a high number of secondary infections - at the population level one speaks of a so-called "overdispersion." These special characteristics of SARS-CoV-2 (asymptomatic aerosol transmission and overdispersion) make the pandemic difficult to control.