Real-time monitoring the transmission potential of COVID-19 in Singapore, February 2020

Abstract

BackgroundThe ongoing COVID-19 epidemic that spread widely in China since December 2019 is now generating local transmission in multiple countries including Singapore as of February 27, 2020.This highlights the need to monitor in real time the transmission potential of COVID-19. In Singapore, four major COVID-19 case clusters have emerged thus far. MethodsHere we estimate the effective reproduction number, Rt, of COVID-19 in Singapore from the publicly available daily case series of imported and autochthonous cases by date of symptoms onset, after adjusting the local cases for reporting delays. We also derive the reproduction number from the distribution of cluster sizes using a branching process analysis. ResultsThe effective reproduction number peaked with a mean value ~1.1 around February 2 nd , 2020 and declined thereafter. As of February 27 th , 2020, our most recent estimate of Rt is at 0.5 (95% CI: 0.2,0.7) while an estimate of the overall R based on cluster size distribution is at 0.7 (95% CI: 0.5, 0.9). ConclusionThe trajectory of the reproduction number in Singapore underscore the significant effects of containment efforts in Singapore while at the same time suggest the need to sustain social distancing and active case finding efforts to stomp out all active chains of transmission.

Transmission potential and severity of COVID-19 in South Korea

“…This aligns well with the sub-exponential growth patterns of COVID-19 in Singapore and all Chinese provinces except Hubei , Tariq et al, 2020.…”

“…(1.1, 95% CI: 1.1, 1.3) as of February 19 th , 2020, reflecting a significant impact of the control interventions that have been implemented in Singapore (Tariq et al, 2020). The estimates of the scaling of growth parameter (p) in our study indicate sub-exponential growth dynamics of COVID-19 in Korea.…”

Transmission potential of the novel coronavirus (COVID-19) onboard the diamond Princess Cruises Ship, 2020

“…unfolded aboard the Diamond Princess Ship, January-February 2020. The overall mean reproduction number in the confined setting reached values as high as ~11, which is higher than mean estimates reported from community-level transmission dynamics in China and Singapore in the range 1.1-7[10][11][12][13][14][15][16]. However, following the implementation of the quarantine period, the overall R t decreased substantially compared to values estimated during the early stage, but it exhibited fluctuations around the epidemic threshold, which likely prolonged the outbreak.Our results indicate that R t declined following the quarantine measures implemented by the Japanese government on February 5 relative to values during the early phase of the outbreak[3].…”

Transmission potential of COVID-19 in South Korea

“…Our estimates of the reproduction number can be compared with earlier estimates reported for the epidemic in China where the estimates of R lie in the range 2-7.1 (1,(23)(24)(25)(26)(27)(28)(29). Moreover, the mean R reached values as high as ~11 for the outbreak that unfolded aboard the Princess Cruises Ship during January-February 2020 (30 Singapore and all Chinese provinces except Hubei (31,32).…”