Once a person who has pneumonia starts on antibiotics, he or she only remains contagious for the next 24 to 48 hours. This can be longer for certain types of organisms, including those that cause the disease tuberculosis. In that case, someone can remain contagious for up to two weeks after starting on antibiotics.

How long is pneumonia contagious?

The average time an individual is contagious from pneumonia is approximately 10 days. However, some cases of pneumonia (particularly pneumonia associated with tuberculosis) can be contagious for several weeks, depending on the form of pneumonia and the type of medical treatment recommended.

Is pneumonia contagious before symptoms appear?

In most cases, infections are contagious for a few days before symptoms appear and for a few days after. The exact length of time a person is contagious depends on the type of microorganism causing the infection. Some forms of pneumonia, such as pneumonia caused by mycoplasma, remain contagious for several weeks.