Pneumonia is an infection of the lungs that can be caused by a variety of pathogens, including viruses, bacteria, and fungi. When you have pneumonia, the tiny air sacs in your lungs become inflamed and can fill with fluid or even pus.

Pneumonia can range from a mild to serious or life-threatening infection and can sometimes lead to death. According to the Centers for Disease Control and Prevention (CDC), over 50,000 people in the United States died from pneumonia in 2015. Additionally, pneumonia is the leading cause of death worldwide for children under 5 years of age.

Who’s at risk for a severe or life-threatening case of pneumonia and why? What are the symptoms to look out for? How can you prevent infection? Read on to learn more.

Pneumonia can affect anyone. But there are some at an increased risk for developing a severe or life-threatening infection. Generally, those at greatest risk have a weaker immune system or a condition or lifestyle factor that affects their lungs.

People that are at an increased risk for having a serious or life-threatening case of pneumonia include:

  • children younger than 2 years old
  • adults aged 65 and older
  • people who are hospitalized, particularly if they’ve been placed on a ventilator
  • individuals with a chronic disease or condition, such as asthma, chronic obstructive pulmonary disease, or diabetes
  • people with a weakened immune system due to a chronic condition, chemotherapy, or an organ transplant
  • those who smoke cigarettes

Pneumonia symptoms may be milder or subtler in many at-risk populations. This is because many at-risk groups have a weakened immune system or a chronic or acute condition.

Because of this, these people may not receive the care that they need until the infection has become severe. It’s very important to be aware of the development of any symptoms and to seek prompt medical attention.

Additionally, pneumonia can worsen preexisting chronic conditions, particularly those of the heart and lungs. This can lead to a rapid decline in condition.

Most people do eventually recover from pneumonia. However, the 30-day mortality rate is 5 to 10 percent of hospitalized patients. It can be up to 30 percent in those admitted to intensive care.

The cause of your pneumonia can often determine the severity of the infection.

Viral

Viral pneumonia is typically a milder disease and symptoms occur gradually. However, it’s important to note that viral pneumonias can sometimes be further complicated when a bacterial infection develops at the same time or following the viral pneumonia.

Bacterial

These pneumonias are often more severe. Symptoms can either develop gradually or come on suddenly and can affect one or many lobes of the lung. When multiple lobes of the lungs are affected, the person typically requires hospitalization. Antibiotics are used to treat bacterial pneumonia. Complications such as bacteremia can also occur.

You may have heard of “walking pneumonia.” Unlike other types, this form of bacterial pneumonia is typically very mild and you may not even know you have it.

Fungal

Fungal pneumonia is typically more common in people with a weakened immune system and these infections can be very serious.

Pneumonia can also be classified by where it is acquired — within the community or within a hospital or healthcare setting. Pneumonia acquired from a hospital or healthcare setting is often more dangerous because you’re already sick or unwell.

Additionally, bacteria pneumonia that’s acquired in a hospital or healthcare setting may be more severe due to the high prevalence of antibiotic resistance.

If you or a loved one has the following symptoms, you should make an appointment with a doctor to be evaluated for possible pneumonia:

  • abnormal body temperature, such as fever and chills or a lower-than-normal body temperature in older adults or people with weak immune systems
  • shortness of breath or difficulty breathing
  • cough, possibly with mucus or phlegm
  • chest pain when you cough or breathe
  • tiredness or fatigue
  • confusion, particularly in older adults
  • nausea, vomiting, or diarrhea

You can help to prevent serious or life-threatening pneumonia infection by doing the following:

Monitoring your health

Be aware of any worrying symptoms, particularly if you have any risk factors. Also, remember that pneumonia can also follow other respiratory infections, so be aware of any new or worsening symptoms if you’re already or have recently been sick.

Getting vaccinated

Many vaccines can help prevent infections that can potentially cause pneumonia. These include:

Practicing good hygiene

Wash your hands frequently, particularly:

  • after using the bathroom
  • before eating
  • before touching your hands, face, and mouth

Use hand sanitizer if soap isn’t available.

Living a healthy lifestyle

Avoid smoking cigarettes and be sure to keep your immune system boosted through regular exercise and a healthy diet.

Pneumonia is a lung infection that can sometimes lead to severe or life-threatening illness and even death.

If you or a loved one is experiencing symptoms of pneumonia, it’s important to go see a doctor, particularly if you have certain risk factors. If left untreated, the infection can rapidly worsen and become life-threatening. Early diagnosis is key and leads to better outcomes.