A secondary infection is an infection that occurs during or after treatment for another infection. It may be caused by the first treatment or by changes in the immune system.
Two examples of a secondary infection are:
- A vaginal yeast infection after taking antibiotics to treat an infection caused by bacteria
- Pneumonia caused by bacteria or fungi after having an upper respiratory infection (like a cold) that was caused by a virus
Dockrell DH, Sundar S, Angus BJ. Infectious disease. In: Ralston SH, Penman ID, Strachan MWJ, Hobson RP, eds. Davidson's Principles and Practice of Medicine. 23rd ed. Philadelphia, PA: Elsevier; 2018:chap 11.
Reid PT, Innes JA. Respiratory disease. In: Ralston SH, Penman ID, Strachan MWJ, Hobson RP, eds. Davidson's Principles and Practice of Medicine. 23rd ed. Philadelphia, PA: Elsevier; 2018:chap 17.
Review Date 9/1/2021
Updated by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.