They are a common cause of infections in the upper respiratory tract and can lead to persistent otitis media, pneumonia, meningitis, sepsis and more.
Þeir eru algeng orsök sýkinga í efri öndunarvegum sem geta leitt til þrálátra miðeyrnasýkinga, lungnabólgu, heilahimnubólgu, blóðsýkingar o.fl.