In April, the US Centres for Disease Control and Prevention (CDC) released six additional symptoms, including chills, muscle pain and sore throat, which may appear two to 14 days after exposure to the virus.

The symptoms of Covid-19 according to the CDC are:

• Fever
• Shortness of breath
• Dry cough
• Chills
• Repeated shaking with chills
• Muscle pain
• Headache
• Sore throat
• New loss of taste or smell

These include:

• Persistent pain or pressure in the chest
• Mental confusion or low responsiveness to stimuli
• Bluish tinge to the lips or face.

If you have a fever, difficulty breathing or other severe or concerning symptoms, wear a surgical mask, seek medical attention promptly and reveal your recent travel history.

China’s National Health Commission has warned that people who have been infected but show no symptoms can be contagious, with research showing these asymptomatic cases have led to sporadic clusters of the disease.

Limited studies suggest the viral loads in the respiratory samples of asymptomatic patients – a key metric of an infected person's transmission capability – do not demonstrate distinct differences from those of confirmed cases, according to Chang Jile, head of the commission's disease control bureau.

People of all ages can be infected by the coronavirus and most infected people will develop mild to moderate symptoms and recover without requiring special treatment, according to the WHO. Some may develop more severe forms of the disease, such as pneumonia.

However, older people and those with underlying or pre-existing medical conditions, such as asthma, diabetes and heart disease, have a higher risk of developing severe disease and death, the WHO said.