Pneumonia is caused by bacteria and viruses that are contagious, according to WebMD. Typically, a healthy immune system fights off the sources of pneumonia before the condition takes hold; however, if someone in a household shows the symptoms of pneumonia, everyone should take extra care to wash their hands frequently and not share eating implements or toothbrushes, explains KidsHealth.
Everyday Health explains that pneumonia is an infection in the lungs. This infection arises when certain bacteria, viruses or fungi enter the lungs and cause infection. Thus while pneumonia can be passed between people, it is not a direct pneumonia virus that is contagious but rather the bugs that can lead to pneumonia. Viral sources of pneumonia tend to spread the most easily.
Those with compromised immune systems are at an increased risk of contracting pneumonia. Everyday Health states that those with diabetes, heart disease and COPD face increased risk of pneumonia as do those recovering from surgery, those undergoing treatment for cancer and alcoholics.
Pneumonia typically lasts about two weeks, according to WebMD. The damage to the lungs may lead to more persistent difficulties, with fatigue and weakness sometimes lasting for up to a month after the infection is resolved.