Take a detailed history to ascertain the level of risk for COVID-19 and assess the possibility of other
causes. Travel history is key; it is crucial for timely diagnosis and to prevent further transmission.
The diagnosis should be suspected in patients with fever and/or signs/symptoms of lower respiratory
illness (e.g., cough, dyspnoea) who reside in or have travelled to a country/area or territory reporting local
transmission of COVID-19 or who report close contact with a confirmed or probable case of COVID-19 in
the 14 days prior to symptom onset.
The clinical presentation resembles viral pneumonia, and the severity of illness ranges from mild to
severe. Approximately 80% of patients present with mild illness, 14% present with severe illness, and 5%
present with critical illness. Early reports suggest that illness severity is associated with older age and the
presence of underlying health conditions.
Some patients may be minimally symptomatic or asymptomatic. Large-scale screening in non-endemic
areas may pick up more of these types of patients. A milder clinical course has been reported in cases
identified outside of China, with most patients being healthy adults.
Based on an early analysis of case series, the most common symptoms are:  
Less common symptoms include:
• Sputum production
• Sore throat
• Chest pain
• Abdominal pain.
Approximately 90% of patients present with more than one symptom, and 15% of patients present with
fever, cough, and dyspnoea. It appears that fewer patients have prominent upper respiratory tract or
gastrointestinal symptoms compared with SARS, MERS, or influenza.  Patients may present with
nausea or diarrhoea 1 to 2 days prior to onset of fever and breathing difficulties. Most children present
with mild symptoms, without fever or pneumonia. However, they may have signs of pneumonia on chest
imaging despite having minimal or no symptoms.   Retrospective reviews of pregnant women
with COVID-19 found that the clinical characteristics in pregnant women were similar to those reported
for non-pregnant adults.  A retrospective case series of 62 patients in Zhejiang province found
that the clinical features were less severe than those of the primary infected patients from Wuhan City,
indicating that second-generation infection may result in milder infection. This phenomenon was also
reported with MERS.
Perform a physical examination. Patients may be febrile (with or without chills/rigors) and have obvious
cough and/or difficulty breathing. Auscultation of the chest may reveal inspiratory crackles, rales, and/or
bronchial breathing in patients with pneumonia or respiratory distress. Patients with respiratory distress
may have tachycardia, tachypnoea, or cyanosis accompanying hypoxia.