How Is Pneumonia Spread?
The germs that cause pneumonia are usually found in the mouth and nose of the infected person. They can be spread easily to another person, either through the air or by touching a contaminated surface. Typically, they enter the person's body through their mouth, nose, or eyes. When this happens, a battle begins -- the person's immune system tries to kill the germs, while the germs try to multiply.
Although a person with either viral or bacterial pneumonia is contagious, that person's germs are more likely to cause an upper respiratory infection in another person (such as the common cold) than pneumonia. This is because many of the viruses and bacteria that cause people to get pneumonia are the same ones that cause upper respiratory infections.
(For more information on how pneumonia is spread, click Is Pneumonia Contagious? This article takes an in-depth look at how people transmit pneumonia, including things you can do to limit your chances of getting sick.)