Individuals infected with C. pneumoniae are generally asymptomatic. In symptomatic cases, infection most commonly present with a cough, fever, headache, and malaise. However, they can also develop laryngitis, pharyngitis, coryza and pneumonia. Initial symptoms have a gradual onset but can persist over extended periods of time and some may experience a continuous cough and malaise for several weeks or months, despite antimicrobial therapy.

C. pneumoniae is spread from person-to-person through respiratory droplets. It can also spread through contact with objects contaminated with respiratory droplets as the bacteria can survive on surfaces for up to 30 hours. C. pneumoniae is associated with a long incubation period of 3-4 weeks. with a period of infectivity ranging from 2-14 days.