Bacterial pneumonia is the most common type of pneumonia in the community. Community-acquired bacterial pneumonia is not considered contagious in the traditional sense of the word.
I have personally treated thousands of patients hospitalized with common bacterial pneumonia in the last 15 years of my medical practice. Once someone is diagnosed with pneumonia, friends, family, and co-workers are concerned that they may also get pneumonia due to contact with the person hospitalized with bacterial pneumonia. That is a concern with specific types of very contagious pneumonia, but common bacterial pneumonia, also called community-acquired bacterial pneumonia, is different.
In this article, I will explain why community-acquired bacterial pneumonia is not considered contagious in the traditional sense, and why people close to the person with bacterial pneumonia need not worry too much. I will specifically explain the following points:
- Why community-acquired bacterial pneumonia does not require isolation or special precautions to avoid spreading the disease
- Who needs to worry about possibly catching community-acquired bacterial pneumonia
- Why getting vaccinated against community-acquired pneumonia is important for certain people
This article is based on my personal experience as well as a thorough review of medical literature.
Why community-acquired bacterial pneumonia does not require isolation or special precautions
Although not considered very contagious, community-acquired pneumonia is still an infectious disease. It is caused by microorganisms that could be transmitted from one person to another. However, we don’t put people suffering from community-acquired bacterial pneumonia in isolation because, as the name applies, the bacteria causing community-acquired pneumonia is everywhere in the community.
Most people who inhale particles containing the bacteria responsible for community-acquired pneumonia only get colonized by bacteria. They don’t develop pneumonia. It is not practical to avoid contact with people that are colonized with this bacteria because it is simply everywhere. Up to 60% of children and 10% of adults may carry this bacteria in their upper respiratory tract. If you live in a community, it is very difficult to avoid contact with this bacteria.
People who are hospitalized with community-acquired bacterial pneumonia represent a small fraction of people who have been colonized by this bacteria. That is why we don’t put these people in any special isolation room. Under normal circumstances, there are no restrictions for visitors who want to visit their loved ones hospitalized with community-acquired bacterial pneumonia.
There are many more people treated at home for this type of pneumonia than hospitalized with it. These people get diagnosed with pneumonia at the doctor’s office and are sent home on antibiotics. Many people diagnosed with pneumonia at the doctor’s office are nervous about going home because they are worried that they may infect their family members.
As with people hospitalized with community-acquired bacterial pneumonia, people being treated at home also need not worry about spreading the disease to friends and family except for certain specific situations that we will discuss shortly.
Who needs to worry about possibly catching community-acquired bacterial pneumonia
Although community-acquired bacterial pneumonia is not considered contagious to normal people, there are certain situations where it can be contagious and dangerous to specific people. Here are a few examples:
- People who have just received a bone marrow transplant
- People getting immune system suppressing treatment
- People with very low white blood cell counts due to certain types of chemotherapy during cancer treatment
- People suffering from certain immune system disorders
If you are in any of the above categories, you need to avoid contact with anyone that is sick with any communicable disease including community-acquired bacterial pneumonia. When your immune system isn’t working, the same bacteria that colonizes most people can make you sick with an invasive life-threatening illness.
In addition to not visiting people with community-acquired pneumonia, you need to follow these other guidelines to prevent getting serious life-threatening infections:
- Avoid crowded places: As you know, most people who are colonized with pneumonia-causing bacteria don’t have any symptoms, but they can still spread the disease to you if your immune system is compromised. It is important to avoid any crowded place if you have decreased immunity.
- Wear a mask: Wearing a mask whenever you are in the presence of other people may help you prevent getting sick with a respiratory infection.
- Keep visitors to a minimum: As any of your visitors may carry bacteria, you can reduce the chance of getting it by keeping the number of visitors to a minimum. It is understandable that your friends and family would want to visit you when you are sick. But if you have a poor immune system, you need to tell your visitors to stay away. If they truly care about you, they would understand.
- Have essential visitors wear a mask: Having your visitors wear a mask will significantly reduce the risk of getting germs from your visitors.
Why getting vaccinated against community-acquired pneumonia is important for certain people
You have learned that pneumonia-causing bacteria are everywhere, and it is very difficult to avoid exposure. If you are a young and healthy adult, you don’t need to worry about getting pneumonia because your immune system will fight it, and you most likely won’t get sick.
The most common bacteria that causes community-acquired pneumonia in adults is called Streptococcus pneumoniae, or simply pneumococcus. There is a highly effective vaccine against pneumococcus. It will help your immune system get ready to fight this bacteria if it enters your body.
It is recommended that you get this vaccine if you are an adult in any of the following categories:
- 65 years old or older: As you age, your immune system gets weaker. Once you reach age 65, it is important to get yourself protected against community-acquired bacterial pneumonia by getting the pneumococcal vaccine.
- If you have a drinking problem: If you drink a lot of alcohol during a regular basis, you are at a very high risk of getting pneumonia. If you are not ready to give up drinking yet, you can at least get some protection against pneumonia by getting the pneumococcal vaccine.
- If you smoke cigarettes: Smoking damages the protective barrier of your lungs, reducing your immunity. If you smoke, you need the pneumococcal vaccine to protect you against pneumonia.
- If you have a history of heart problems: When you have chronic heart problems, you are at a higher risk of getting pneumonia. The pneumococcal vaccine will reduce your chances of getting pneumonia.
- If you have COPD or similar lung problems: Chronic lung disease makes it easier for bacteria to invade deeper into your lungs and cause pneumonia. You need the pneumococcal vaccine to reduce your risk.
- If your diabetes is out of control: High blood sugars interfere with your white blood cells and make it harder for them to fight an infection. Having uncontrolled diabetes increases your risk of getting any infection, including pneumonia.
- If you have liver problems: The liver makes many proteins that are essential to the body, including special proteins required to help prevent infections. Having a chronic liver disease makes you susceptible to pneumonia. You can decrease your risk by getting the pneumonia vaccine.
In conclusion, community-acquired bacterial pneumonia is an infectious disease and is communicable from person to person, but it is not considered contagious in the traditional sense because it is present everywhere in the community. It is not practical to avoid being exposed to the bacteria that causes community-acquired pneumonia. If you are at a high risk of getting pneumonia, it is more practical to reduce your risk by getting vaccinated rather than avoiding exposure.
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5949087/
https://pubmed.ncbi.nlm.nih.gov/25785969/