With the rapidly evolving situation, China is no longer the epicentre of the COVID-19 outbreak and the virus has spread to many other countries around the world.
To minimise the risk of widespread community transmission, contact tracing and enhanced surveillance (such as enhanced pneumonia surveillance and testing of patients in intensive care units) is essential.
Efforts should be focused on identifying locally acquired cases and containment to prevent further transmission in the community.
This was proposed by a local team of researchers in a paper titled ‘Investigation of three clusters of COVID-19 in Singapore: implications for surveillance and response measures’, published in The Lancet on 16 March 2020.
The paper looked at data from three clusters (involving a Chinese tour group, company conference and a church) that show the transmissibility of COVID-19 in community settings beyond household clusters. This is also what we are seeing now around the world. It is thus important for countries to do active case-finding among close contacts of cases to prevent such clusters from spreading.
The study also highlights the importance of emphasising personal and hand hygiene as a key public health message that countries should adopt. According to the authors, cases in the three clusters are probably attributable to close or prolonged interactions, and that direct transmission could be possible by contact, or indirect transmission via common-touch surfaces.
The authors note some limitations of the study including the small sample size and recall bias. They were also unable to address asymptomatic transmission and said that further studies should be done to better understand disease transmissibility of asymptomatic cases.
The paper was produced by the Singapore COVID-19 Novel Coronavirus Outbreak Research Team, which is made up of researchers from various local institutions including SSHSPH; Ministry of Health, Singapore (MOH); National Centre for Infectious Diseases; Agency for Science, Technology and Research (A*STAR); Lee Kong Chian School of Medicine, Nanyang Technological University; and NUS Yong Loo Lin School of Medicine.
The data analysis on disease transmission and figures was conducted by Ms Rachael Pung, Public Health Officer at MOH, in consultation with Associate Professor Alex Cook and Assistant Professor Hannah Clapham.