Immunocompromised: Understanding a Weakened Immune System
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is immunocompromised?
Immunocompromised is a condition in which the immune system is weakened and cannot fight infections as easily as it should, so people get sick more often or more severely. Causes include HIV, cancer, diabetes, corticosteroids, chemotherapy and transplants. Warning signs include frequent infections and slow recovery. Infections can spread and cause sepsis and septic shock, which can be fatal. [1]
What the research says
Vaccines work less well in many immunocompromised groups. A systematic review and meta-analysis of 82 studies found that after one COVID-19 vaccine dose, seroconversion was about half as likely in people with blood cancers (risk ratio 0.40), immune-mediated inflammatory disorders (0.53) and solid cancers (0.55) than in immunocompetent controls, and organ transplant recipients were 16 times less likely to seroconvert (0.06). After a second dose, only about a third of transplant recipients had seroconverted. (Lee et al., BMJ, 2022)
Breakthrough infections are more likely despite vaccination. A systematic review found that, after vaccination, the relative risk of COVID-19 breakthrough infection was higher than in the general population for people with cancer (1.4), HIV (1.92), chronic kidney disease (2.26), immunodeficiency (2.55) and organ transplants (6.94). (Bytyci et al., Immun Inflamm Dis, 2024)
What does it mean to be immunocompromised?
Being immunocompromised means your immune system, the network of cells and organs that defends against germs, is not working properly. It is weakened and cannot fight infections as easily as it should. You can be born with a condition that compromises your immune system, or infections, medications, cancer or other health conditions you acquire later in life can weaken it. [1]
Immunocompromised is also described as having a weakened immune system. The term immunosuppression is usually used when the weakening comes from certain treatments or from illnesses you were not born with. Whatever the term, the result is the same: your body's natural shield is lowered, so germs are more likely to cause harm. [1]
Recognizing the signs of a weakened immune system
On its own, being immunocompromised does not cause symptoms you can feel. It shows up in how your body responds to illness. Getting sick a lot or having unusually long-lasting infections are the most common signs, but getting sick often does not by itself mean your immune system is not working properly, because the kind of illness matters. Young children getting colds all the time, for example, is completely normal. Frequent bacterial infections, pneumonia or certain other illnesses are more concerning. [1]
Indicator | Description |
|---|---|
Unusual infections | You get illnesses that most people fight off without getting sick |
Severe response | Illnesses that mildly affect most people make you severely sick |
Slow recovery | Illnesses linger or take a longer time to recover from |
Complications | You are more likely to develop complications than others, such as pneumonia after a respiratory virus |
Viral reactivation | You get sick again with viral infections you have had before, such as Epstein-Barr virus or varicella-zoster virus (the virus behind shingles) |
Vaccine failure | You do not develop antibodies after getting vaccinated |
If you have an illness that causes immunosuppression, such as certain cancers, you might also notice fatigue, night sweats, recurring fevers, unintended weight loss or swollen lymph nodes. A healthcare provider may suspect a compromised immune system if you get infections that most people fight off easily, such as Pneumocystis pneumonia, symptomatic cytomegalovirus (CMV) infections, or fungal infections that spread outside your lungs. [1]
Common causes of a compromised immune system
Diseases, the side effects of certain medications, and receiving an organ or stem cell transplant are the most common causes of a compromised immune system. Many diseases can destroy immune cells or affect your body's ability to make them properly. [1] Diseases that can cause immunosuppression include:
Primary immunodeficiency: Any condition you are born with that weakens your immune system. [1]
HIV (human immunodeficiency virus). [1]
Cancer: Leukemia, lymphoma and multiple myeloma are most likely to affect your immune system, but other cancers can too. [1]
Other conditions: Diabetes, autoimmune diseases, sickle cell disease, liver cirrhosis and viral hepatitis. [1]
People without a thymus (where T cells mature) or a spleen (an organ that contains white blood cells and controls their levels) also have a compromised immune system. [1]
Medications and treatments that suppress immunity
Some treatments, like radiation and chemotherapy, weaken your immune system as a side effect. Others suppress it as part of how they work. For example, a bone marrow transplant usually destroys all or most of your immune system to replace it with one that works better, and many medicines for autoimmune diseases weaken your immune system to stop it from attacking healthy cells. [1] Common examples include:
Cancer therapies: Chemotherapy and radiation therapy. [1]
Corticosteroids: Medicines such as prednisone, prednisolone and dexamethasone. [1]
Other immunosuppressive medicines: Azathioprine, cyclosporine, hydroxychloroquine, leflunomide, methotrexate and sulfasalazine. [1]
Transplants: Bone marrow or solid organ transplants. [1]
Diagnosis, treatment and complications
Healthcare providers diagnose a compromised immune system, and the conditions that cause it, by testing your blood and body tissues. Tests may include a complete blood count (CBC), antibody testing, flow cytometry (which counts immune cells), genetic testing, urinalysis, HIV testing, lymph node, bone marrow or liver biopsies, and CT scans or other imaging. [1]
Treatment depends on the cause. Providers can treat certain underlying conditions to strengthen your immune system again, for example with antiretroviral therapy for HIV or cancer treatments. If you get an infection, your provider will probably treat it right away with antibiotic, antifungal, antiviral or antiparasitic medicines, depending on the type of infection. [1]
The complications of being immunocompromised can be life-threatening. Because your body cannot fight off infections as well, they can spread throughout your body, leading to organ damage, sepsis and septic shock (extremely low blood pressure), all of which can be fatal. Go to the nearest emergency room if you are severely ill. [1]
Preventing infections and when to seek care
Most conditions that weaken your immune system are not preventable, so avoiding infections from other people is usually the best way to prevent severe complications. You can reduce your infection risk by:
Washing your hands frequently and following safe food handling practices. [1]
Getting recommended vaccinations. Ask your provider which ones make sense for you, because certain types of vaccines can make you sick if you have a weakened immune system. [1]
Limiting exposure. Avoid people who are sick and large crowds, especially during cold and flu season, and carry a mask and hand sanitizer with you. [1]
Knowing the warning signs. Ask your provider what signs of infection to look out for and what to do if you have them. [1]
Always go to the emergency room if you have signs of a serious infection, including a fever (in many cases, any temperature above 100.4°F or 38°C), confusion or an altered mental state, a severe headache, a stiff neck, frequent vomiting or diarrhea, or wounds that are red, swollen, painful, oozing or warm to the touch. [1]
Not everyone with a weakened immune system is immunocompromised to the same degree. Some people are immunocompromised for only a short time, while others have conditions or take medicines that affect their immune system for life. Many of these conditions are manageable, but most require lifelong vigilance to prevent infections or treat them right away. Talk with your healthcare team about what to expect in your situation. [1]
Learn more. For more evidence-based health guides, visit Rinnit.com.
Frequently Asked Questions
Does getting a lot of colds mean I am immunocompromised?
Not necessarily. Frequent colds are common, especially in young children. What matters is the kind of illness. Frequent bacterial infections, pneumonia or unusually long-lasting infections can be signs of a weakened immune system.
Can I get vaccinated if I am immunocompromised?
Ask your healthcare provider which vaccines make sense for you. Recommended vaccinations help reduce your risk of certain infections, but certain types of vaccines can make you sick if you have a weakened immune system. Some immunocompromised people also do not develop antibodies after vaccination.
Is being immunocompromised the same as having an autoimmune disease?
No, but they are related. Many medicines that treat autoimmune diseases weaken the immune system to stop it from attacking healthy cells, which can make a person immunocompromised.
Can stress weaken my immune system?
Stress alone does not make someone immunocompromised. The term usually refers to a weakening caused by a disease, medicines or other treatments. Managing stress is still a healthy habit that can support your immune system.
What is the most dangerous infection for an immunocompromised person?
Any infection can be serious. Providers watch especially for infections that most people fight off easily, such as Pneumocystis pneumonia, symptomatic cytomegalovirus (CMV) infections and fungal infections that spread beyond the lungs.
Can I still live a normal life if I am immunosuppressed?
Many people do, with extra precautions such as frequent handwashing, avoiding sick people, planning ahead and close follow-up with their healthcare team. What feels like a minor adjustment to one person may change another person's life completely.
Does HIV weaken the immune system?
Yes. HIV is one of the diseases that can cause immunosuppression. Antiretroviral therapy can reduce the amount of HIV in your body to levels so low that it no longer affects your immune system.
How do I know if my medication is an immunosuppressant?
Check with your doctor or pharmacist. Common examples include corticosteroids such as prednisone and medicines used for autoimmune conditions, such as methotrexate.
Can you be born immunocompromised?
Yes. Conditions you are born with that weaken the immune system are called primary immunodeficiency.
Does a missing spleen affect my immune system?
Yes. The spleen contains white blood cells and controls their levels, so people without a spleen, or without a thymus, have a compromised immune system.
What should I do if I have a fever and am immunocompromised?
Ask your provider in advance what to do. In many cases, a temperature above 100.4°F (38°C) is a reason to go to the emergency room, as are confusion, severe headache, stiff neck, frequent vomiting or diarrhea, or wounds that are red, swollen, painful or warm.
Can diet improve a compromised immune system?
Ask your healthcare provider whether physical activity or food choices can make a difference for you. Treatment for a weakened immune system depends on its underlying cause.
What is sepsis?
Sepsis is a life-threatening emergency in which the body's response to an infection causes widespread inflammation and organ damage. Go to the nearest emergency room if you are severely ill.
Are there different levels of being immunocompromised?
Yes. Not everyone with a weakened immune system is immunocompromised to the same degree. For example, a bone marrow transplant usually destroys all or most of the immune system before replacing it with one that works better.
Can my immune system ever go back to normal?
It depends on the cause. Some people are immunocompromised only for a short period, while others have conditions or take medicines that affect their immune system for life.
References
Cleveland Clinic. Immunocompromised (Immunosuppressed). Cleveland Clinic. Last updated December 17, 2024. https://my.clevelandclinic.org/health/diseases/immunocompromised
Lee ARYB, et al. Efficacy of covid-19 vaccines in immunocompromised patients: systematic review and meta-analysis. BMJ. 2022;376:e068632. PMID 35236664. https://doi.org/10.1136/bmj-2021-068632
Bytyci J, et al. Immunocompromised individuals are at increased risk of COVID-19 breakthrough infection, hospitalization, and death in the post-vaccination era: A systematic review. Immun Inflamm Dis. 2024;12(4):e1259. PMID 38661301. https://doi.org/10.1002/iid3.1259
Medical disclaimer
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Comments