The importance of superspreading events
Empirical observation throughout the SARS-CoV-2 pandemic has shown the outsized role of superspreading events in the propagation of SARS-CoV-2, wherein the average infected person does not transmit the virus. Our results suggest the same dynamics likely influenced the initial establishment of SARS-CoV-2 in humans, as only 29.7% of simulated epidemics from the primary analysis went on to establish self-sustaining epidemics. The remaining 70.3% of epidemics went extinct…Furthermore, the large and highly connected contact networks characterizing urban areas seem critical to the establishment of SARS-CoV-2. When we simulated epidemics where the number of connections was reduced by 50% or 75% (without rescaling per-contact transmissibility), to reflect emergence in a rural community, the epidemics went extinct 94.5% or 99.6% of the time, respectively…The high extinction rates we inferred suggest that spillover of SARS-CoV-2-like viruses may be frequent, even if pandemics are rare.
Here is the paper, via the excellent Kevin Lewis.