Is Pneumonia Contagious?

March 3, 2016

Is pneumonia contagious? The answer is…well, yes…no…maybe! But read on because it is not a simple yes or no answer.

What is it and is it contagious?

Pneumonia is a lower respiratory lung infection that causes inflammation in one or both lungs. Once infected, the lung’s air sacs inflame and fill with fluid and pus. Pneumonia comes in different forms and is caused primarily by bacteria or viruses, and less commonly by fungi and parasites. The type of germ determines who gets pneumonia, how serious the illness can become, and how pneumonia is treated.

It is contagious when the causative pathogens (usually bacteria or viruses) are expelled when an infected person coughs and produces droplets. These expelled droplets contain the bacteria or virus that causes the pneumonia. Bottom line, you don’t catch pneumonia. You catch the germs that cause it!

You can catch the germs that cause pneumonia in the most common of places, and the environment you visit on a daily basis may contribute to how susceptible you are to the disease.

For the most part, bacterial pneumonia is much less contagious after antibiotics have been administered for 24-48 hours. For viral pneumonia, the person becomes less contagious after the symptoms have begun to recede, especially the fever. This may occur one or two days after the person is free of fever, but one may still shed some infectious virus for a week or so with some types of viral pneumonia.

What causes pneumonia?

There are more than 30 different organisms that cause pneumonia — primarily bacteria, viruses and fungi –and to a lesser degree other infectious agents, chemicals or inhaled food.

Bacterial Pneumonia

Bacteria are the most common cause of pneumonia in adults.Types of bacterial pneumonia include:

  • Streptococcus pneumonia: This is the most common cause of bacterial pneumonia in adults and can be prevented by a vaccine called Pneumovax, which is currently recommended to start at age 65 or in anyone younger whose health is compromised.
  • Mycoplasma pneumonia: Mycoplasma pneumonia usually affects younger adults who work in crowded areas such as schools, homeless shelters, or prisons.
  • Chlamydophila pneumonia: This type of pneumonia is a mild pneumonia that usually affects people over age 60.
  • Haemophilus influenza type B: Haemophilus influenza type B can be prevented with a vaccine, called the Hibvaccine. It’s recommended for all children younger than 5.
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Bacterial pneumonia symptoms include fever, chills, cough, shortness of breath and fatigue. Others include rapid breathing, pain when coughing or breathing deeply, and loss of appetite. Bacterial pneumonias tend to be more serious with more noticeable symptoms than other types.

Risk factors for bacterial pneumonia include:

  • Having an underlying lung disease like asthma or COPD
  • Having a systemic disease like diabetes
  • Having a weekend immune system
  • Being very old or very young
  • Being disabled
  • Abusing alcohol
  • Smoking

Antibiotics treat pneumonia by controlling the bacterial or fungal infection. The initial choice of antibiotic depends on the organism presumed to be causing the infection. Depending on the level of illness, the physician may treat the patient with antibiotics either at home or in the hospital.

A mild case of pneumonia is called walking pneumonia

Walking pneumonia is a non-medical term to describe a mild case of pneumonia and it is also known as atypical pneumonia. It is different from the more serious cases of pneumonia caused by typical bacteria. People who have walking pneumonia are seldom confined to bed or need to be hospitalized. Some may even feel well enough to go to work and carry on with other routines much like when the person suffers from a cold.

Viral Pneumonia

Viral pneumonia viruses are responsible for about a third of all pneumonias, and they are most common for children under 5.Adults suffering from viral pneumonia tend to recover in about one to three weeks, but there is an increased risk for bacterial pneumonia. Adults with viral pneumonia can also expect to develop fever and headache and will also experience a sore throat, loss of appetite and muscle pain. Viral pneumonia is more contagious than bacterial and fungal pneumonia because viruses are more likely to spread from person to person.

Antibiotics are ineffective against viral pneumonia. The physician will typically treat the symptoms: fever, cough and dehydration.

Fungal Pneumonia

There are three types of fungi living in soil which are known to cause pneumonia and they are:

  • Coccidioidomycosis which is common in the Southwest US
  • Histoplasmosis found in the middle of the country
  • Cryptococcus which is found in bird droppings all cross the US

Most people who inhale these fungi do not get sick unless they have a weak immune system and then they develop pneumonia. Another fungus, pneumocystis jirovecii can generate an infection in people with a weakened immune system, such as those who have HIV/AIDS.

Aspiration Pneumonia

Aspiration pneumonia can develop after a person inhales food, liquid, gases, or dust.

A strong gag reflex or cough will usually prevent aspiration pneumonia, but a person may be at risk if he or she has a hard time swallowing or have a decreased level of alertness. Chemical – or toxin-related pneumonia can be seen in older people who have difficulty swallowing such as those who have suffered a stroke. Once the lungs have been irritated by breathing in food or stomach contents, a bacterial infection can develop.

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When to seek medical care?

A physician should be seen if the following symptoms are present: fever and cough (especially if a productive cough with yellow, green, brown sputum) after having flu-like symptoms.

A person should go to an ER if these symptoms appear – chest pain, shortness of breath, confusion and high fever. If a person has a chronic health problem like diabetes, HIV, or other problems that result in a depressed immune system, he or she should see a physician immediately or go to an ER if even mild pneumonia symptoms develop.

Complications from pneumonia included sepsis, pleural effusion and empyema. Pneumonia can be fatal in up to 30% of severe cases that are managed in the intensive-care setting.

How is pneumonia diagnosed?

Pneumonia can be diagnosed by a doctor listening to a patient’s lungs. Certain sounds heard through a stethoscope may indicate infection. In addition, a chest x-ray can help identify which part of a patient’s lung is infected. An x-ray also can show abnormal fluid collections which also can help diagnose pneumonia. The patient may also have blood drawn. Laboratory tests can show that the immune system is working properly to fight off infection.


Texas MedClinic was established in 1982 by Dr. Bernard T. Swift, Jr., as a group medical practice that specializes in urgent care and occupational medicine. Texas MedClinic has grown to 19 locations in San Antonio, New Braunfels, Austin, and Round Rock. Texas MedClinic is staffed with 82 medical providers including physicians, physician assistants and nurse practitioners and over 450 employees.

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