武漢肺炎疫情在中國境內迅速擴散，如何有效地控制住疫情不在全球流行擴散，是國際公共衛生面對的緊急事件，根據2020年2月19日新英格蘭臨床期刊報告指出，要能有效地控制住疫情之前， 有幾個重要問題須釐清：第一、完整武漢肺炎疾病病程，從無臨床症狀到因病死亡。第二、2019年新型冠狀病毒 (COVI-19) 傳播途徑有哪些? 第三、感染者的特性，尤其是無臨床症狀之感染者。第四、那些危險因子會造成嚴重臨床症狀，進而因病死亡? 現階段需要更多資料與更多不同領域的研究結果，才能正確回答這些問題，所幸目前除中國以外，其他國家疫情尚能有效地控制， 但中國以外的國家需要對COVI-19此新興傳染病投入更多的研究，方能全盤了解COVI-19此新興傳染病。
The epidemic of 2019 novel coronavirus (now called SARS-CoV-2, causing the disease Covid-19) has expanded from Wuhan throughout China and is being exported to a growing number of countries, some of which have seen onward transmission. Early efforts have focused on describing the clinical course, counting severe cases, and treating the sick. Experience with the Middle East respiratory syndrome (MERS), pandemic influenza, and other outbreaks has shown that as an epidemic evolves, we face an urgent need to expand public health activities in order to elucidate the epidemiology of the novel virus and characterize its potential impact. The impact of an epidemic depends on the number of persons infected, the infection’s transmissibility, and the spectrum of clinical severity.
Thus, several questions are especially critical. First, what is the full spectrum of disease severity (which can range from asymptomatic, to symptomatic-but-mild, to severe, to requiring hospitalization, to fatal)?
Second, how transmissible is the virus?
Third, who are the infectors — how do the infected person’s age, the severity of illness, and other characteristics of a case affect the risk of transmitting the infection to others? Of vital interest is the role that asymptomatic or presymptomatic infected persons play in transmission. When and for how long is the virus present in respiratory secretions?
And fourth, what are the risk factors for severe illness or death? And how can we identify groups most likely to have poor outcomes so that we can focus prevention and treatment efforts?
Author：Marc Lipsitch, David L. Swerdlow, Lyn Finelli, et al.