Sepsis and Impaired Immune System

Your immune system protects you from many illnesses. It’s your defense system. It recognizes dangers to the body and fights bacteria, viruses, and other dangerous microbes to keep you healthy. An impaired – or weakened – immune system doesn’t protect you as well from infection.

Your immune system is made up of cells, proteins, and organs. For most people, it works well, although they still may get sick or contract an infection from time to time. This is why we get vaccinations against illnesses like tetanus, measles, and polio. Vaccines trick your body into thinking it already had the illness, making you immune to it. Other medications, like antibiotics, antivirals, antifungals, and antiparasitics help your body fight infections that do develop. These are all antimicrobials.

For a variety of reasons, many people are immunocompromised. Their immune system either doesn’t work well or not at all.  People with an impaired immune system are at higher risk of contracting infections, which increases their risk of developing sepsis. These infections may also be more severe.

Sepsis, which was often called blood poisoning, is the body’s life-threatening response to infection. Like strokes or heart attacks, sepsis is a medical emergency that requires rapid diagnosis and treatment.

Suggested Citation:
Sepsis Alliance. Sepsis and Impaired Immune System. 2024.

Updated January 19, 2024.


More About Impaired Immune Systems


There are several reasons for immunosuppression. Here are some:

Certain illnesses

Diseases like primary immune deficiency  make it difficult for people to fight infections. There are over 400 types of PI, according to the Centers for Disease Control and Prevention.

Cancer treatment

Some diseases, like cancer, are treated with chemotherapy. While chemotherapy can be quite effective in fighting the cancer cells, it can also destroy some of the body’s healthy cells, including those that help fight infection. People undergoing chemotherapy must avoid exposure to anything that could cause illness.

Some people with cancer and other serious illnesses require a bone marrow or stem cell transplant. This also makes it hard for your body to fight infection. To prepare people for such a transplant, they must undergo chemotherapy and sometimes radiation therapy. This will destroy cancer cells and depress the immune system, so the body doesn’t reject the transplant.

Organ transplants

Organ transplants are occurring more often now, allowing people to live longer and to improve their quality of life. However, the organ recipient’s body sees these new organs as invaders, so the immune system will try to fight them. To keep the body from rejecting the organ, people with organ transplants must take immunosuppressant drugs, or anti-rejection drugs. These drugs also can reduce the ability to fight other infections, such as colds, the flu, and more.


Your spleen is a small organ in the upper part of your abdomen, near your stomach. It helps filter your blood and stores platelets and white blood cells, which fight infection. Certain illnesses can reduce how well your spleen works, such as sickle cell anemia. Technically, you can live without your spleen. People without spleens must be particularly careful to avoid exposure to anything that may cause an infection.

Other medications

Some medications are very useful in helping treat illnesses, even preventing death. However, they can also have serious side effects, like making you more susceptible to developing an infection. These include medicines like corticosteroids, such as prednisone, and TNF inhibitors, which may be prescribed for autoimmune diseases like rheumatoid arthritis or psoriasis.

Infection Prevention

An impaired immune system is a risk factor for infection. Infection prevention is vital. This includes proper hand washing, up-to-date vaccinations, and treating infections as soon as possible. Good nutrition is also essential. Not consuming enough nutrients for your needs, can lower your body’s ability to fight infection. If you are immunocompromised and suspect an infection, mention your immunocompromised status to the healthcare professionals. This will help them with your care.

Related Resources

Information Guide

Immune System

  • To submit this form you are required to enter your first name, last name, a valid email address and your role.

Information Guide


  • To submit this form you are required to enter your first name, last name, a valid email address and your role.

Charles Butters

Charles (Chuck) was my husband of 41 years who died from sepsis 3 years ago after a valiant fight with non-Hodgkin lymphoma. (Sepsis and Cancer) He was diagnosed with lymphoma and had surgery, chemo, and radiation. He remained in remission for over a year and he used this time to travel. He experienced relapse of lymphoma and started another round of chemo with a goal of stem cell transplant. (Sepsis and Impaired Immune System) After the first treatment, he began having some confusion, fever, and weakness. We went immediately to the ED but it was already too late. He was ... Read Full Story

Submit Your StoryView More Stories

Kerry Hecht

I got sick in December 2020 when Covid was in full swing. I was perfectly fine – completely normal. About halfway through a meeting, I started getting very tired and got terrible chills. I assumed, like everyone did then, that I had Covid. When I went to the urgent care to get tested – it was negative, and they sent me home. I loaded up on aspirin and was fine – actually, for a few days. Then, it returned. With a high fever, chills, and vomiting, I returned to the urgent care to get tested again for COVID-19. I was ... Read Full Story

Submit Your StoryView More Stories

James L.

Hi. My husband, James (Jay for short) had spent years on an immunosuppressant medication for rheumatoid arthritis. We knew there was risk of infection, but he had always been fine. (Sepsis and Impaired Immune System) One morning in July 2019, he awoke extremely sick. It seemed like food poisoning so I sent him back to bed. But because of Covid I was taking his temperature just in case. Well his temperature spiked and he was in and out of consciousness. I rushed him to the hospital where he was admitted in septic shock. He was in kidney failure and having ... Read Full Story

Submit Your StoryView More Stories

Alexa Foutch

I am a 16 time sepsis survivor. 3x septic shock survivor. What started as an asthma attack that put me on a ventilator, and I ended up vomiting which turned into aspiration pneumonia, however, I just kept getting sick after that though. I was septic with COVID and other illnesses. Come to find out I have primary ammagammabulemia. Because of sepsis I had to give up PTA school, am on supplemental oxygen 24/7 due to chronic respiratory failure, and have been on life support 14 times, I struggle every day with the after-effects of sepsis. I have been diagnosed with ... Read Full Story

Submit Your StoryView More Stories

Donna Swain

Unfortunately, I am all too familiar with sepsis. I am very prone to UTIs, but it is rare that I recognize that I have one because I get no symptoms, until it’s too late! (Sepsis and Urinary Tract Infections) Without the usual symptoms of a UTI, the infection gets out of control and I quickly becomes septic. I must be very careful with this because in 2015, I had a liver transplant (unrelated to my UTIs or sepsis). (Sepsis and Organ Transplants, Sepsis and Impaired Immune System) Unfortunately, when I become septic, I get very confused, disoriented, and unable to ... Read Full Story

Submit Your StoryView More Stories

Other Topics

Impaired Immune System