When an individual is immunocompromised, their immune system does not work as well as it should. This can cause more instances of illness and a higher likelihood of becoming seriously sick. There are many groups of people who are at risk of serious complications from seemingly ordinary illnesses because they are immunocompromised. This includes people living with certain medical conditions like HIV, cancer, diabetes, autoimmune disorders or liver disease. It also includes anyone taking immunosuppressive drugs (post-transplant or for an autoimmune disease) and people undergoing treatments like chemotherapy or radiation.
As a medical oncologist, Dr. Michael Grant’s patients fall into this group. He spoke with us about how he protects his patients from pneumonia and what he suggests when they have unexplained symptoms. “Immunocompromised patients are more at risk of contracting things that are atypical or opportunistic, meaning that since the person’s immune system is lower than a typical patient, they are at a great disadvantage,” he explained. This is why he takes even the most unlikely diagnosis into consideration.
Causes and Complications for Immunocompromised
Pneumonia can be caused by bacteria, viruses, and in less common situations, fungi. This lung infection, which causes the lungs' air sacs (alveoli) to become inflamed and fill up with fluid, can make it difficult to breathe. People with a healthy immune system typically experience symptoms like chest pain, fever and cough that produces mucus and sputum. But people with a weak immune system have to also be wary of shortness of breath or a dry cough, as they may have pneumonia even without displaying the usual symptoms. “I tell my patients that if they have any new or different respiratory symptoms compared to their baseline, like sputum color changes, if there is more than usual, or if their cough is just getting worse, they should contact someone,” says Dr. Grant.
For patients with compromised immune systems, the worry is that the infection will overwhelm the immune system and cause serious complications. Sepsis is a life-threatening condition where the infection triggers the body to overreact, causing damage to its own tissues and organs, which can lead to organ failure. Cardiac complications can be caused by low blood pressure. And if the pneumonia significantly compromises someone’s lung function, preventing oxygen exchange, their oxygen levels can plummet, which is also life-threatening. “It can be tough to know if your oxygen level is dropping,” Dr. Grant explains. “Sometimes it can just feel like increased shortness of breath, that’s why you need to be in a clinic or emergency department to get your oxygen levels checked.”
How Treatment and Recovery Differ
Most of the time, even individuals with a weakened immune system can be treated without being admitted to the hospital for pneumonia. If the infection is severe, you may be treated in the hospital with supplemental oxygen support, IV fluids and antibiotics and/or other in-hospital treatments.
In both cases, doctors have to determine what caused the infection so they can prescribe antibiotics, antivirals or antifungals. To pinpoint the cause, your doctor will ask about your medical history and will conduct a physical exam. They may need to order blood tests, a sample of your mucus, a chest X-ray or CT scan. If a person is on immunosuppressive treatments, they may have to interrupt their normal treatment regime so that the medication can work properly. “It depends on what they are being used for, but doctors will want to factor that in when considering treatment,” said Dr. Grant. “If that immune system is really low, antibiotics may take a while to work, and the infection may last longer. In general, it will take these patients longer to return to baseline than someone with a normal immune system.”
Treatment for any disease when someone has a suppressed immune system is complicated, which is why they should work closely with their healthcare provider and be sure to ask questions.
Preventing Severe Pneumonia
When it comes to prevention, Dr. Grant believes that maintenance care is especially important for people with a suppressed immune system. Vaccines can be lifesaving, be sure to be up to date on your personal vaccination recommendations, guided by your healthcare provider. This includes:
- An annual flu shot, the nasal spray flu shot is not recommended for individuals who are immunocompromised
- At least one dose of COVID-19 vaccine, you may need additional doses
- An RSV vaccine
- Pneumococcal vaccines according to your healthcare provider's schedule, this helps prevent the most common type of bacterial pneumonia
Your healthcare provider may recommendation additional vaccines as well. “There is a lot of information now about when you should be getting vaccines and who fits into those high-risk groups,” said Dr. Grant. “It is essential for immunocompromised patients to stick to this schedule as any infection can turn into something more severe.”
In addition, some immunocompromised individuals may qualify for prophylactics, a group of preventive medications that target some bacteria, viruses and fungal organisms. But it is important to work closely with your healthcare provider as this is a case-by-case basis. “Sometimes for patients that are really immunocompromised, we recommend broad fungal treatment so that they do not develop fungal pneumonia, because it can become very severe if you do develop it.”
Dr. Grant also stresses that the other often underrecognized preventive steps that everyone can take is maintaining a healthy lifestyle. “Staying active, exercising regularly can help your immune system sort of counteract the immunosuppressive regimens some patients are on,” he said. “Talk to your doctor but eating healthy and exercising are always a good idea.”
Blog last updated: February 4, 2026
