Less frequently, these viruses are associated with lower respiratory tract infection, including pneumonia, which primarily occurs in immunocompromised individuals and infants. Most people will be infected with one or more of these viruses at some point in their lives, with reinfections occurring throughout life.
In adults, these viruses account for 4% to 15% of acute respiratory disease annually, and up to 35% during peak periods. In children, the illness rates reaches 8% annually, with a peak of up to 20%. In temperate climates infections mainly occur during the winter months. Human coronaviruses are the second most common cause of the common cold, after rhinoviruses.
