pneumonia is caused by a variety of organisms. the time that a person is contagious varies and depends on the organism that causes the particular case of pneumonia. some types of pneumonia are spread by aerosolized particles (called airborne infectious organisms) but most are acquired by organisms that are already found in your mouth. tuberculosis can also cause pneumonia and that can take two weeks or longer of therapy before an infected person is considered no longer contagious. the most common types of pneumonia such as pneumococcal pneumonia require other conditions besides exposure to an infected person to spread.
how long after you begin antibiotic treatment for pneumonia are you no longer contagious?