Signs and Symptoms

In general, Chlamydia pneumoniae infection is a mild illness that most commonly causes an upper respiratory tract infection, such as sore throat or an ear or sinus infection. Common symptoms include:

• Runny or stuffy nose
• Being tired (fatigue)
• Low-grade fever
• Hoarseness or loss of voice (laryngitis)
• Sore throat
• Slowly worsening cough that can last for weeks or months
• Headache

C. pneumoniae can also cause lower respiratory infections like bronchitis and lung infections like pneumonia. While not all people with pneumonia caused by C. pneumoniae have laryngitis, most do, separating it from the other types of bacterial pneumonia. It can take at least 21 days after someone is exposed to the bacteria before they start showing signs or symptoms of illness. Symptoms can also continue for several weeks after they start.