Though pneumonia is often thought of as a single illness, it actually comes in many different forms. While each type can cause the dangerous inflammation in your lungs—the result of an infection that leads to fluid or pus collecting in the lungs—the specific type of pneumonia can determine risk of severity, symptoms, and even treatment options.
Another thing that the specific type of pneumonia can shed light on: whether or not it's contagious. (Yes, you heard that right: some forms of pneumonia are indeed able to be passed between people). To get more information on those types—and what you need to know about how they present and how to avoid them—we tapped some infectious disease experts. Here's what you need to know about the contagious forms of pneumonia.
Is-Pneumonia-Contagious-GettyImages-1211147099 (NHLBI). Pneumonia causes the air sacs—called alveoli—of the lungs to fill up with fluid or pus. That can lead to uncomfortable symptoms like a cough with or without mucus, fever, chills, and trouble breathing.
Pneumonia can be severe, and sometimes even fatal. "Pneumonia can kill you," David Cutler, MD, a family medicine physician at Providence Saint John's Health Center in Santa Monica, Calif., tells Health. "It used to be one of the leading causes of death in this country and the world. It's only since the development of antibiotics and vaccines to prevent pneumonia that it's no longer the case."
Is pneumonia contagious?
So, yes, it can be. Here's where the certain types of pneumonia come into play, since whether or not pneumonia is contagious depends on which type you have (or someone you know has).
In the most basic terms, pneumonia can be caused by either a bacterial, viral, or fungal infection, according to the Centers for Disease Control and Prevention (CDC). Out of those three main causes, the ones that are communicable (i.e., passed from person to person) are those of the bacterial and viral variety. (Fungal pneumonia, according to the American Lung Association, is typically seen in people with compromised immune systems and occurs after they've been exposed to large amounts of certain fungi, usually in soil or bird droppings.)
Though both are contagious, there are some differences between bacterial and viral pneumonia—here's what to know about each.
Bacteria are a common cause of pneumonia in adults, the NHLBI says. And, while plenty of types of bacteria can cause bacterial pneumonia, Streptococcus pneumonia is the biggest cause in the U.S. However, Mycoplasma pneumoniae and Legionella pneumophila can also cause bacterial pneumonia.
You can get bacterial pneumonia on its own, or "you can develop it as a secondary infection after having the cold or flu," pulmonary critical care expert Reynold Panettieri, MD, director of the Institute for Translational Medicine and Science at Rutgers University, tells Health.
Bacterial pneumonia can be treated with antibiotics, and you shouldn't be contagious after a few days of being on the medication, John E. McGinniss, MD, a pulmonologist with Penn Medicine, tells Health.
Viral pneumonia can happen as a direct result of viruses that infect your airways and lungs, like the flu (which is caused by the influenza virus) or the common cold (rhinovirus), the NHLBI says. In children, respiratory syncytial virus (RSV) is the most common cause of viral pneumonia.
But viral pneumonia isn't just caused by the cold and flu. SARS-CoV-2, the virus that causes COVID-19, can also cause pneumonia, Dr. McGinniss points out.
As a whole, "viral pneumonia is more contagious than bacterial pneumonia," Dr. McGinniss says. That's why, if you're around someone who has viral pneumonia, it's important to take precautions like wearing a mask and practicing careful hand hygiene, he says. However, according to the ALA, most viral pneumonias are not as serious as bacterial pneumonia, nor do they last as long. (The exception to that is pneumonia caused by the influenza virus, which can be very severe and fatal in some cases.)
Viral pneumonia is usually treated with anti-viral medication, according to the NHLBI, although they're not effective against every virus that causes pneumonia.
How can you catch pneumonia—and who’s most at risk?
When pneumonia is caused by either bacteria or viruses, it can spread between people in a variety of ways: being exposed to viral particles through uncovered coughs or sneezes, sharing drinks or utensils with an infected person, or even touching a tissue from or taking care of a person with pneumonia. It's important to note that these are mainly examples of community-acquired pneumonia, which occurs when someone develops pneumonia in the general community, per the CDC.
Anyone can get pneumonia, according to the ALA, but some people are at a greater risk for having severe pneumonia than others. Those include:
- People age 65 and over.
- Children under two years old.
- People with chronic lung diseases like COPD or cystic fibrosis.
- People with serious chronic illnesses, like heart disease, diabetes, and sickle cell disease.
- People with a weakened immune system due to HIV/AIDs, an organ transplant, chemotherapy, or long-term steroid use.
- People with difficulty swallowing.
- Those who had a recent respiratory infection, like a cold, laryngitis, or the flu.
- People who have been recently hospitalized.
- People who abuse drugs and alcohol.
- Exposure to certain chemicals, pollutants, or toxic fumes, including secondhand smoke.
Is there any way to prevent getting a contagious form of pneumonia?
Here's where some vaccines come into play—there are actually a few different ones that can significantly lower your risk (as long as your doctor gives you the all-clear).
- The flu vaccine: "The flu vaccine is actually very effective at preventing bacterial pneumonia, since influenza predisposes you to bacterial pneumonia as a secondary infection," Dr. McGinniss says. He points out that it can also be helpful at preventing viral pneumonia from the influenza virus.
- Pneumococcal vaccines: There are twovaccines available to prevent infections from the pneumococcus bacteria, the most common type of bacteria that causes pneumonia— pneumococcal conjugate vaccine (PCV13) and the pneumococcal polysaccharide vaccine (PPSV23). These are usually recommended for adults over the age of 65 or older, people with chronic diseases, and people who smoke. "The current vaccines are very effective," Dr. Panettieri says.
- The Hib vaccine: Hib stands for Haemophilus influenzae type b, which is a type of bacteria that can cause pneumonia and meningitis. It's recommended for all children under the age of five in the U.S., and is given to babies as young as two months old, the NHLBI says.
- The COVID-19 vaccine: While the vaccines are new, they have been proven to lower your risk of contracting a severe form of the virus, which can include serious complications like pneumonia, Dr. McGinniss points out.
Aside from getting vaccinated, experts stress the importance of careful hand hygiene and doing your best to avoid people who are sick to lower your risk of pneumonia.
If you do happen to develop symptoms of pneumonia, your best bet is to call your doctor and schedule an appointment—they can give you a once-over and determine exactly what you're dealing with (and, if it is pneumonia, possibly which type) so you can receive the correct treatment.
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