Is Pneumonia Contagious?

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

When is pneumonia contagious?

Pneumonia is contagious when the causative pathogens (usually bacteria or viruses) are expelled by an infected person by coughing out infected droplets. These expelled droplets contain the bacteria or virus that causes the pneumonia. These droplets contaminate the mouth or breathing tract of another individual to eventually infect their lungs.

The approximate time when pneumonia becomes contagious varies with the type of infecting agent and may range from one to two days to weeks. In addition, some pneumonias are more highly contagious than others. For example, Mycobacterium and Mycoplasma organisms are highly contagious, but other types, including pneumococcal pneumonia, require optimal conditions to spread to another person and are weakly contagious.

What is the incubation period for pneumonia?

The incubation period for pneumonia depends on the type of pathogen causing the disease, the person's age, and his or her overall health. In general, most pneumonias begin with symptoms similar to those of a cold or the flu that last longer than the flu (about seven to 10 days) and become more severe. The signs and symptoms of pneumonia include

These symptoms may occur as early as one to three days or about a week after "flu-like symptoms" develop.

Medically Reviewed by a Doctor on 6/27/2017

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