The time-varying transmission dynamics of COVID-19 and synchronous public health interventions in China.

OBJECTIVES

We aimed to estimate the time-varying transmission dynamics of COVID-19 in China, Wuhan City, and Guangdong province, and compare to that of severe acute respiratory syndrome (SARS).

METHODS

Data on COVID-19 cases in China up to 20 March 2020 was collected from epidemiological investigations or official websites. Data on SARS cases in Guangdong Province, Beijing, and Hong Kong during 2002-3 was also obtained. We estimated the doubling time, basic reproduction number (R), and time-varying reproduction number (R) of COVID-19 and SARS.

RESULTS

As of 20 March 2020, 80,739 locally acquired COVID-19 cases were identified in mainland China, with most cases reported between 20 January and 29 February 2020. The R value of COVID-19 in China and Wuhan was 5.0 and 4.8, respectively, which was greater than the R value of SARS in Guangdong (R = 2.3), Hong Kong (R = 2.3), and Beijing (R = 2.6). At the start of the COVID-19 epidemic, the R value in China peaked at 8.4 and then declined quickly to below 1.0 in one month. With SARS, the R curve saw fluctuations with more than one peak, the highest peak was lower than that for COVID-19.

CONCLUSIONS

COVID-19 has much higher transmissibility than SARS, however, a series of prevention and control interventions to suppress the outbreak were effective. Sustained efforts are needed to prevent the rebound of the epidemic in the context of the global pandemic.