COVID-19 and SARS are both types of pneumonia caused by different coronaviruses. The main clinical manifestations of COVID-19 are fever, dry cough, and fatigue. A small number of patients may experience nasal congestion, runny nose, sore throat, muscle pain, and diarrhea. Severe cases may develop difficulty breathing and/or low blood oxygen levels. SARS, short for Severe Acute Respiratory Syndrome, typically begins with fever, accompanied by chills, muscle aches, joint pain, headache, and fatigue. A dry cough with little phlegm may be present. In severe cases, patients may experience rapid breathing, shortness of breath, and even respiratory distress. Some patients may also exhibit gastrointestinal symptoms such as diarrhea, nausea, and vomiting. The differentiation between these two diseases primarily relies on pathogen testing, which involves detecting different viral nucleic acids or antibodies.