Using the likelihood-based method to simultaneously estimate initial R t and the SI across 100 imputations of the dataset (Method 1), we estimated aR R t of 1.47 (95% CI: 1.30-1.72) and a mean SI of 2.78 days (95% CI: 1.80-3.75) (Figure 2 ).R R t estimates ranged from 1.31 (95% CI: 1.21-1.48) to 1.54 (95% CI: 1.37-2.03) when the maximal value of the SI ranged from 4 to 8 days.