There are about four strains of coronavirus that cause about 20% of the cases of common cold. However, the COVID-19 virus can cause severe illness because it travels deep into the respiratory tract and infects the lungs. This deep infection can make a person more susceptible for pneumonia. About 80% of the cases of COVID-19 are mild but those with compromised immune systems and the elderly are at greater risk.
Drafted 16 March 2020