The reproductive number was calculated using the serial interval distribution of COVID-19 (Figure 1A). Data was then used to predict reproductive numbers based on 25% and 50% reduction over 10 days based on crew efforts to control the spread of infection.

Figure 1A: The distribution of serial interval (A), the distribution of likely values of reproductive number (R0) with the Maximum-Likelihood (ML) estimation (B), a sample of 1000 likely R0 values using a bootstrap resampling method (C) for COVID-19 on Diamond Princess cruise ship.