The Facts About Pneumonia: Types, Symptoms, and Reducing Your Risk

Medically Reviewed By Adithya Cattamanchi, M.D.

“Pneumonia” is a general term for an infection in one or both lungs. The infection inflames the alveoli, which are the tiny sacs that exchange oxygen and carbon dioxide. Pneumonia can range from mild to serious and life threatening. It is a common infection that can occur at any time of the year. In healthy adults, pneumonia can be a relatively moderate condition that does not require hospitalization. However, it is a common complication of various conditions and can lead to life threatening complications, such as sepsis and respiratory failure.

The American Lung Association (ALA) warns that pneumonia is a frequent cause of death, especially in infants and older adults with chronic diseases or weakened immune systems. 

This article provides an overview of pneumonia, including types and causes. It also discusses symptoms of pneumonia and when to contact a doctor.

What are the different types of pneumonia?

Older man using vaporizer or facial steamer
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Classifying pneumonia is important because it helps guide treatment. The different types of pneumonia include the following.

Aspiration pneumonia

This kind of pneumonia occurs when you inhale particles or large amounts of material into the lungs. The material inhaled could include mouth secretions or stomach contents. This may inflame the lungs and introduce bacteria into them.

Normally, the body can clear small particles that you inhale. There are also mechanisms to prevent inhaling contents from your mouth or stomach. When something inhibits those protective actions, however, aspiration can occur.

Older adults, people who are vomiting, and individuals with swallowing problems or reflux are at risk of this kind of pneumonia. You can also develop it as a result of anesthesia or intoxication with alcohol or drugs.

Community-acquired pneumonia

This type of pneumonia is a leading cause Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source of death and hospitalization worldwide. You can acquire it while living your daily life in your home and community. Bacteria, viruses, and fungi can cause it. Some forms of community-acquired pneumonia are quite mild and do not require bed rest. Others can be serious and require a hospital stay.

Nosocomial pneumonia

This type encompasses hospital-acquired pneumonia and healthcare-acquired pneumonia. You can get it while staying in a hospital or another kind of healthcare facility. This includes long-term care facilities and even outpatient care clinics, such as dialysis clinics.

Bacteria are the most likely Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source cause of this type of pneumonia. These bacteria are generally more dangerous than those that cause community-acquired pneumonia. These bacteria are often hard to treat because they are resistant to standard antibiotics.

People receiving ventilator treatment are at higher risk Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source of developing this type of pneumonia. 

People who are sick or recovering are also less able to fight off nosocomial pneumonia infections.

Fungal pneumonia

Certain fungi can cause pneumonia, particularly in people with weakened immune systems or chronic diseases. These fungi include:

  • Aspergillus species
  • Cryptococcus neoformans
  • Pneumocytis jirovecii

Endemic fungi, which are types of fungi that occur in specific regions, can also cause respiratory conditions, including pneumonia. These endemic fungi include:

  • Coccidioides species, present in the Southwestern United States
  • Histoplasma capsulatum, present in the Mississippi and Ohio River Valleys
  • Blastomyces dermatitidis, present in the upper Midwest
  • Cryptococcus species, present in the Pacific Northwest

Fungal pneumonia is not contagious.

‘Walking pneumonia’

Walking pneumonia is not a medical type of pneumonia. Instead, this is a colloquial term for mild pneumonia that does not require bed rest or hospitalization. However, the ALA advises that even mild cases of pneumonia require self-care and rest for a quick recovery. Talk with your doctor if your symptoms do not go away after a few days or if they become worse.

Pneumonia and COVID-19

Because COVID-19 primarily affects Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source the respiratory system, some people who develop COVID-19 have also developed pneumonia. The Centers for Disease Control and Prevention (CDC) Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source recommends getting the COVID-19 vaccine as a step to lower your risk of pneumonia.

What are the symptoms of pneumonia?

Pneumonia signs and symptoms vary in type and severity. They depend on a variety of factors, such as your age, general health, and medical history. Symptoms are often more severe in people who have chronic illnesses, those with weakened immune systems, children younger than 2 years, and older adults.

During a pneumonia infection, inflamed alveoli can fill with fluid or mucus. This causes typical pneumonia symptoms that include:

How long does pneumonia last?

The recovery time for pneumonia varies from person to person, depending on the severity of the infection. The doctor recommending the treatment plan will give a more accurate prediction of your recovery timeline. 

Some people may be able to return to their regular activities within a week or two. Others may take a month or longer. Lingering fatigue can take a month to resolve, and doctors encourage people to rest when they are tired.

Talk with your doctor about your symptoms. They will let you know when it is OK for you to return to your regular activities. Returning to the tasks of daily life too soon may cause a relapse in illness.

The recovery period can be longer if complications develop. Older adults, children, and people with weakened immune systems may be more likely to develop complications from the infection. Sepsis, acute respiratory distress syndrome (ARDS), and respiratory failure can cause longer recovery times. 

Serious symptoms that might indicate a life threatening condition

According to the ALA, pneumonia can be life threatening in some cases. Seek immediate medical care by calling 911 for any of the following serious symptoms:

What causes pneumonia?

Bacteria and viruses are the most common causes of pneumonia. The infection usually spreads from person to person when someone with the infection coughs, talks, or sneezes. This sprays droplets containing bacteria into the air where others can inhale them. However, not everyone who is around these germs will get sick. It can depend on risk factors.

The ALA reports that Streptococcus pneumoniae bacteria are the most common bacterial cause of community-acquired pneumonia. Other bacteria include Chlamydia pneumoniae, Haemophilus influenzae, Legionella pneumoniae, and Mycoplasma pneumoniae.  

L. pneumoniae are the bacteria responsible for Legionnaires disease, while M. pneumoniae bacteria cause walking pneumonia.

Common viruses that cause community-acquired pneumonia include influenza viruses, respiratory syncytial virus, and SARS-CoV-2.

Other causes of pneumonia include:

  • choking or aspiration of food or liquid into the lungs
  • a fungal or yeast infection
  • inflammation of the lungs due to exposure to toxic gases or lung irritants
  • near drowning
  • trauma

What are the risk factors for pneumonia?

Pneumonia can occur in any age group and population. However, the risk is highest for children ages 2 years or younger and for older adults. A number of other factors increase the risk of developing pneumonia, including:

Reducing your risk of pneumonia

Not all people with risk factors will get pneumonia. You can lower your risk of catching or spreading pneumonia by:

  • getting your COVID-19 vaccination, including recommended booster doses
  • avoiding contact with people who have pneumonia, a cold, or the flu
  • avoiding exposure to air pollutants, toxic gases, and lung irritants, such as heavy smoke
  • avoiding long periods of immobility
  • covering your mouth and nose with your elbow or a tissue when sneezing or coughing
  • following your doctor’s advice for exercise and deep breathing exercises
  • following your treatment plan for chronic illnesses and injuries
  • not smoking
  • washing the hands frequently with soap and water for at least 20 seconds
  • getting the pneumococcal vaccine if you are an older adult, though you can get it at a younger age if you have a medical condition, as recommended by your primary care professional

Childhood vaccines that prevent pneumonia include Hib, MMR, pneumococcal, and varicella.

How do doctors diagnose pneumonia?

To diagnose pneumonia, your doctor will take a medical history, perform an exam, and order testing. Questions your doctor may ask include:

  • What symptoms are you experiencing?
  • How long have you had these symptoms?
  • Do your symptoms interfere with your ability to do activities or interrupt sleep?
  • What, if anything, seems to make your symptoms better or worse?
  • Are you coughing up phlegm? If so, what color is it?
  • Have you ever had pneumonia before?
  • Have you had your pneumococcal and COVID-19 vaccines?
  • What medical conditions do you have?
  • What medications do you take?

During the exam, your doctor will listen to your lungs and breathing. Tests they may order include:

  • blood tests to check your blood counts and look for signs of infection
  • a chest X-ray to make images of your lungs
  • pulse oximetry to check your blood oxygen saturation
  • sputum culture to see what pathogen is causing pneumonia 

If you require hospitalization for pneumonia, doctors may need to perform additional testing. This may include more imaging exams and more invasive lung tests, such as bronchoscopy.

What are the treatments for pneumonia?

The goals of pneumonia treatment include reducing your risk of serious complications and controlling your symptoms to allow you to rest and recover. Doctors may suggest managing mild to moderate cases in generally healthy adults at home. More severe cases or infections in infants, older adults, or people with chronic diseases often require hospitalization.

Bacterial pneumonia treatment requires antibiotics. Antibiotics are not effective for treating viral pneumonia. Other pneumonia treatments include: 

  • bronchodilators to help ease breathing and relieve shortness of breath
  • cool-mist vaporizer
  • fluids to prevent dehydration
  • medications to relieve fever and body aches
  • oxygen therapy to help relieve shortness of breath and ensure that vital organs, such as the heart and brain, get enough oxygen
  • rest

Pneumonia vaccines

Pneumococcal vaccines help prevent the effects of bacterial pneumonia caused by S. pneumoniae. Although vaccination will not prevent all cases of the lung infection from developing, it can prevent serious complications, promote milder symptoms, and reduce recovery time. 

There are two types of pneumococcal vaccines that can reduce the likelihood of developing pneumonia. The CDC Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source recommends pneumococcal vaccination for children younger than 2 years and older adults over 65 years. Doctors may also recommend the vaccine to people with chronic diseases or weakened immune systems, regardless of age.

Both types of the pneumococcal vaccine are highly effective in preventing pneumonia. 

Influenza, or the flu, is a highly contagious viral infection that can cause pneumonia. The ALA recommends the yearly flu vaccine to help prevent pneumonia. Each year, the flu vaccines administered reflect the current strains that are circulating. Although they are not completely effective at blocking all cases of influenza, they can offer some important protection against the virus. 

Learn about the factors that determine how effective flu vaccines are here.

The CDC Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source also recommends COVID-19 vaccination, including booster shots, as a way to lower your risk of contracting pneumonia. This lung infection has been a complication of COVID-19 for some people.

What are the potential complications of pneumonia?

In some people — especially infants, older adults, and people with chronic diseases — complications of pneumonia can be severe, even life threatening. They can include:


Pneumonia is an infection that causes inflammation in the air sacs within the lungs. Viruses, bacteria, and fungi can cause pneumonia.

Viral pneumonia and bacterial pneumonia are contagious. Someone may acquire pneumonia from their day-to-day routine, during a hospital stay, or as a result of exposure to certain fungi in their environment.

Treatment for bacterial pneumonia involves taking antibiotics to kill the bacteria. Treatments for viral pneumonia focus on managing symptoms and allowing you to rest and recover.

Receiving the pneumococcal vaccine and the full course of the COVID-19 vaccination is a key step in lowering your risk of pneumonia infection.

Because complications of pneumonia can be severe or even life threatening, it is important to contact your primary care doctor or another healthcare professional for symptoms of pneumonia, including a loose, wet cough, chest pressure, and fever and chills.

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Medical Reviewer: Adithya Cattamanchi, M.D.
Last Review Date: 2022 Mar 31
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