The impacts of diagnostic capability and prevention measures on transmission dynamics of COVID-19 in Wuhan

LIANG, Jingbo; Yuan, Hsiang-Yu

Background: Although the rapidly rising transmission trend of COVID-19 in Wuhan has been controlled in late February 2020, the outbreak still caused a global pandemic afterward. Understanding Wuhan COVID-19 transmission dynamics and the effects of prevention approaches is of significant importance for containing virus global transmission. However, most of the recent studies focused on the early outbreaks without considering improvements in diagnostic capability and effects of prevention measures together, thus the estimated results may only reflect the facts in a given period of time. Methods: We constructed a stochastic susceptible-exposed-infected-quarantined-recovered (SEIQR) model, embedding with latent periods under different prevention measures and proportions of documented infections to characterize the Wuhan COVID-19 transmission cross different stages of the outbreak. The epidemiological parameters were estimated using a particle filtering approach. Results: Our model successfully reproduced the dynamics of the Wuhan local epidemic with two peaks on February 4 and February 12 separately. Prevention measures determined the time of reaching the first peak and caused an 87% drop in the R_t from 3.09 (95% CI, 2.10 to 3.63) to 0.41 (95% CI, 0.18 to 0.66). An improved diagnostic capability created the second peak and increased the number of documented infections. The proportion of documented infections changed from 23% (95% CI, 20% to 26%) to 37% (95% CI, 33% to 41%) when the detection kits were released after January 26, and later up to 73% (95% CI, 64% to 80%) after the diagnostic criteria were improved.