Before revision: The Coronavirus Disease 2019 ( COVID-19 ), has infected more than 170 ,000 people globally and resulted in over 6 ,000 deaths over a three-month period. Contrary to mainstream views, there is growing literature on pre-symptomatic and asymptomatic individuals contributing significantly to the disease outbreak . Several recent studies on serial infection yielded a mean interval of around 4 days, shorter than the mean symptom onset time of 5-7 days, and negative serial interval in more than 10\% of the cases. These observations highlight the urgent need to quantify the pre-symptomatic transmission for adequate global response. In this paper, we develop an epidemic model driven by pre-symptomatic transmission. Within the model construct, the infectiousness of a viral carrier on a given day is identified with their symptom onset probability , which we characterise through extensive studies of the clinical literature.
After revision: The Coronavirus Disease 2019 ( COVID-19 ), has infected more than 170 ,000 people globally and resulted in over 6 ,000 deaths as of March 26, 2020. Swift government response to contain the outbreak requires accurate and continuous census of the infected population, particularly with regard to viral carriers without severe symptoms. We take on this task by converting the symptom onset time distribution , which we characterise through extensive studies of the clinical literature.