The ongoing COVID-19 epidemic that has spread widely in China since December 2019 is now generating local transmission in several countries including Singapore of February 19, 2020. This highlights the need to monitor transmission potential of unfolding SARS-CoV-2 outbreaks in real time. In particular, five major COVID-19 clusters have emerged in Singapore. Here we estimate the effective reproduction number, Rt, for Singapore from the daily case series of imported and autochthonous cases by date of symptoms onset, after adjusting the local cases for reporting delays, using a generalized growth model and employing a renewal equation. We also derive the reproduction number from the distribution of cluster sizes using a branching process analysis. As of February 19th, 2020, our results indicate that the mean effective reproduction number Rt is at 1.1 (95% CI: 1.1,1.3) while an estimate of Rt based on cluster size distribution is at 0.63 (95% CI: 0.4, 1.05). These estimates underscore positive impact 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.
### Competing Interest Statement
The authors have declared no competing interest.
### Funding Statement
G.C. is supported by NSF grants 1610429 and 1633381.
### Author Declarations
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Tariq Amna, Lee Yiseul, Roosa Kimberlyn, Blumberg Seth, Yan Ping, MA Stefan, Chowell Gerardo. (2020). Real-time monitoring the transmission potential of COVID-19 in Singapore, February 2020. Cold Spring Harbor Laboratory Press