2019年12月以來，中國湖北省武漢市發現多起不明原因肺炎病例，其臨床表現與病毒性肺炎相似。經實驗室檢測，確認其致病原為新型冠狀病毒。隨著疫情的蔓延，中國其他省市及境外多個國家也出現此類病例。2020 年2 月，世界衛生組織將此疾病命名為coronavirus disease 2019(COVID-19,新冠肺炎)，新型冠狀病毒也正式命名為severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, 新冠肺炎病毒)。目前認為經呼吸道飛沫傳染與接觸傳染為SARS-CoV-2 主要的傳播途徑。COVID-19 潛伏期一般為14 天內，大部分是四到五天。疾病早期的傳染性最高。臨床表現以發燒、呼吸道症狀、腹瀉與嗅覺味覺異常為主。分子生物學檢查是診斷COVID-19 急性感染的最主要方法。

In December, 2019, a cluster of pneumonia cases of unknown cause emerged in Wuhan, Hubei, China, with clinical presentations resembling viral pneumonia. Genetic sequencing analysis indicated a novel coronavirus. With the spread of the epidemic, such cases have also been found in other parts of China and other countries. The World Health Organization designated the disease COVID-19, which stands for coronavirus disease 2019. The virus that causes COVID-19 is designated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Transmission of SARS-CoV-2 is thought to occur via respiratory droplets and close contact. The incubation period for COVID-19 is thought to be within 14 days after exposure, mostly four to five days. Patients might be more infectious in the earlier stage of infection. Clinical manifestations include fever, respiratory tract symptoms, diarrhea, and smell or taste disorders. The diagnosis of COVID-19 is made by detection of SARS-CoV-2 RNA by reverse-transcription polymerase chain reaction (RT-PCR).