Evaluating new evidence in the early dynamics of the novel coronavirus COVID-19 outbreak in Wuhan, China with real time domestic traffic and potential asymptomatic transmissions

Can Zhou

The cumulative number of infected individuals in Wuhan on Feb. 7, 2020 is estimated at 80,084 on average with a 95% credible interval of [63060, 98567] individuals. Due to the elevated population outflow since Jan. 1, 2020, the number of cumulative infected individuals in Wuhan is approximately linear between day 31 and day 51, then appears to stabilize afterwards, and then increases exponentially after the date Wuhan was quarantined (Figure 9 ). The predicted pattern closely resembles the trend of the cumulative number of officially confirmed cases in Wuhan with a time lag of approximately 3 days (Figure 1) . Assuming a constant time lag of 3 days, the confirmation rate of this disease has been low, i.e., less than 10%, in January 2019 but has steadily increased ever since ( Figure 10 ). On Feb. 10, 2020, the overall case confirmation rate is estimated at 23.37% on average with a 95% credible interval of [18.72%, 29.26%]. The time lag between the onset of symptoms and official confirmation of the case probably have decreased with time due to people's increased awareness of this disease and also the reduced procedural burden to confirm a case with newer versions of the case definition from the Chinese CDC. To evaluate other time lags, the estimated case confirmation rate was calculated with lags between 1 and 5 days. These time lags produced similar results on the case confirmation rate on Feb. 10, 2020 (Table 2) .