Fig. 2.

(A) Degree of superspreading quantified by the dispersion parameter $k$ (where $k<1$ indicates significant superspreading) during different periods of the outbreak. Let $T$ be the day of announcing the shelter-in-place order: Period 1 is time $t<T$, period 2 is $\left[T,T+14\right)$, and, finally, period 3 is $t>T+14$. Overall, about the top 2% of cases (that have highest mean number of offspring) directly infected 20% of the total infections. (B) Mean number of offspring generated by cases in each age group. Red dots represent those cases that have mean offspring $\ge$ 8. The younger age group (<60 y) tends to have more cases that produce an extreme number of offspring, and also a larger average (blue lines) of the mean number of offspring. Overall means of $k$ also tend to be similar or smaller among the younger group: 0.53 for the younger group versus 0.82 for the older group in Cobb County, 0.57 versus 0.54 in DeKalb, 0.46 versus 0.64 in Fulton, 0.6 versus 0.6 in Gwinnett, and 0.39 versus 0.62 in Dougherty.