Comprehensive overview of COVID-19 based on current evidence.

In December 2019, twenty-seven pneumonia patients with unknown causes originated in South China seafood market in Wuhan. The virus infection spread rapidly and swept through China in less than a month. Subsequently, the virus was proven a novel coronavirus and named SARS-CoV-2. The outbreak of novel coronavirus has been determined as a Public Health Emergency of International Concern (PHEIC) by WHO on January 31, 2020. Similar to other coronaviruses like the Middle East Respiratory Syndrome (MERS) CoV and Severe Acute Respiratory Syndrome (SARS) CoV, the novel coronavirus was reported to spread via respiratory droplets and close contact from human to human, which means the virus is highly infectious and dangerous. Unfortunately, till now the virus has spread to over 200 countries/territories/areas around the world and the Coronavirus Disease 2019 (COVID-19) outbreak is continuing to grow. Currently, information sharing and transparency are essential for risk assessment and epidemic control in all endemic areas. In this article, we compared SARS-CoV-2 with SARS-CoV and influenza virus, discussed current researching progress of COVID-19, including clinical characteristics, pathological changes, treatment measures, and so on.