A study conducted by researchers from several Israeli and American universities has shown that around 10% of coronavirus carriers are responsible for around 80% of secondary infections.
The study, published on the MedRxiv website, analyzed 212 coronavirus sequences to trace the origins and spread of the virus. The researchers also assessed the reproduction rate of the virus (the "R" rate), before and after social distancing measures were applied, and found that without social distancing, the R rate was around 2 to 2.6, and dropped by two-thirds after social distancing measures were applied.
"Between 1 and 10 percent of infected individuals result[ed] in 80% of secondary infections," the study's authors concluded, adding that, "our findings ... demonstrate the effectiveness of social distancing measures."
Similar studies conducted elsewhere, including a large-scale study in China, have produced similar results.