number has shown it to be consistently below 1, suggesting that containment efforts are successful (Pung et al, unpublished data). However, several challenges lie ahead. Firstly, the longer the outbreak persists, the more chains of community transmission and missed cases are present, and the more difficult it will be to link cases and contain spread. Contact tracing and quarantine are resource-intensive activities and may not be sustainable in the long run. Secondly, some individuals who continue to work or attend social functions while symptomatic are driving disease spread, leading to substantial community Downloaded from https://academic.oup.com/jtm/advance-article-abstract/doi/10.1093/jtm/taaa039/5804843 by guest on 22 March 2020 transmission. Thirdly, with global spread, the force of infection from imported cases will be substantial, leading to new waves of infection. As Singapore is a travel hub with high reliance on trade, sustained border control measures may not be practical with global disease spread, and it may not be feasible to completely shut a country’s borders for a prolonged duration. These factors may result in a rise in cases, and additional measures will be required to achieve a balance between containing disease spread and reducing the overall health and socioeconomic impact due to community transmission. Conclusion Early detection of cases through surveillance and aggressive contact tracing around known cases has helped to contain spread of the outbreak in Singapore. Together with other healthcare, border and community measures, they allow the COVID-19 outbreak to be managed without major disruption to daily living. Countries could consider these measures for a proportionate response to the risk of COVID-19. Author contributions: All authors contributed equally to the literature review, data collection and writing of the manuscript. Declaration of interests: We declare no competing interests. References 1. World Health Organization. Coronavirus disease (COVID-2019) situation report 49 (10 Mar 2020). https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200309-sitrep-49- covid-19.pdf (11 March, 2020, date last accessed). 2. Wilder-Smith A, Chiew CJ, Lee VJ. Can we contain the COVID-19 outbreak with the same measures as far SARS? Lancet Infect Dis 2020. https://doi.org/10.1016/S1473-3099(20)30129-8. 3. Our World in Data. How many tests for COVID-19 are being performed around the world? http://www.ourworldindata.org/covid-testing-10-march (11 March, 2020, date last accessed). 4. Novel Coronavirus Pneumonia Emergency Response Epidemiology Team. The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19) in China. Zhonghua Liu Xing Bing Xue Za Zhi 2020; 41(2):145-151. 5. Ng Y, Li Z, Chua YX et al. Evaluation of the effectiveness of surveillance and response measures for the first 100 patients with COVID-19 in Singapore. MMWR Morb Mortal Wkly Rep 2020 (in press). 6. World Health Organization. Coronavirus disease (COVID-19) technical guidance: Surveillance and case definitions. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical- guidance/surveillance-and-case-definitions (11 March, 2020, date last accessed).