eng Science and Education Publishing American Journal of Infectious Diseases and Microbiology 2328-4064 2020-09-10 8 3 113 117 10.12691/ajidm-8-3-4 AJIDM2020834 article Yen Shen Wong vegans@live.com.my 1 Dzawani Muhamad 2 Soon Hin How 3 Mohamed Sapian Mohamed 4 Nasrah Mohd Arif 4 Tze Vee Soh 4 Suzana Mohd Hashim 4 Norazmi Abdullah 5 Department of Internal Medicine, Pekan Hospital, Pahang, Malaysia Infectious Disease Unit, Department of Internal Medicine, Tengku Ampuan Afzan Hospital, Pahang, Malaysia Respiratory Medicine Unit, Department of Internal Medicine, International Islamic University Malaysia, Pahang, Malaysia State Health Department of Pahang, Malaysia Hospital Director, Tengku Ampuan Afzan Hospital, Pahang, Malaysia Coronavirus disease 2019 (COVID-19) is highly contagious in symptomatic patients as it is thought to be transmitted through respiratory droplets. However, it is debatable whether asymptomatic COVID-19 patients are contagious due to lack of data. From 1st March to 15th April 2020, a total of 247 COVID-19 cases were admitted to Tengku Ampuan Afzan Hospital and 1010 close contacts were identified. We studied the epidemiological and clinical outcomes in asymptomatic subjects, as well as estimated the metrics of disease transmission between asymptomatic, symptomatic, and pneumonia subjects. From a total of 125 asymptomatic subjects, majority (n=116, 92.8%) remained asymptomatic upon discharge. Only 9 (7.2%) subjects developed mild symptoms after admission. Seven subjects had abnormal chest radiograph suggestive of pneumonia, and 22 subjects (17.6%) were found to have mild liver impairment. None of the asymptomatic subjects required oxygen support, inotropic support or ICU care during admission. Fifteen second generation COVID-19 cases were found transmitted from the asymptomatic group, with an attack rate of 3.9%, which was statistically significantly lower compared to the symptomatic (7.6%) or pneumonia groups (25.7%, p<0.001). In conclusion, asymptomatic COVID-19 patients show excellent clinical outcome. They are infectious but had a lower transmission risk compared with symptomatic or pneumonia patients. http://pubs.sciepub.com/ajidm/8/3/4/ajidm-8-3-4.pdf Asymptomatic COVID-19 patients clinical outcome Coronavirus disease 2019 (COVID-19) Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Transmission risk