Information for Patients and Caregivers

Photo of a man receiving chemotherapy

People with cancer who are treated with chemotherapy are more likely to get infections because of their weakened immune system.

People with cancer who are treated with chemotherapy are more likely to get infections because of their weakened immune system. Cancer and chemotherapy can damage your immune system, reducing your numbers of infection-fighting white blood cells and making it harder for your body to fight infections.

An infection can also lead to sepsis, the body’s extreme response to an infection. It is a life-threatening medical emergency.

Having cancer can make you more likely to get severely ill from COVID-19. Treatments for many types of cancer can weaken your body’s ability to fight off disease. Having a history of cancer may increase your risk.

What Is an Infection?

You get an infection when germs enter your body and multiply, causing illness, organ and tissue damage, or disease. Bacteria and viruses cause infections.

How Does Chemotherapy Increase My Risk for Getting an Infection?

1. Chemotherapy
Photo of a woman receiving chemotherapy

Chemotherapy drugs treat cancer by killing the fastest-growing cells in the body—both cancer cells and good cells.

2. Neutropenia
Illustration of normal blood cells and blood cells with neutropenia

White blood cells are good cells that help your body fight infections. Chemotherapy kills many of these cells. This is a side effect called neutropenia.

3. Infection
Photo of a man taking his temperature because he feels sick

Germs enter your body. With fewer white blood cells, your body can’t kill the germs as well as it could before you started chemotherapy. So you’re more likely to get sick.

What Should I Do If I Think I Have an Infection?

Call your doctor right away, even if this happens in the middle of the night. This is considered an emergency. Don’t wait until morning. Keep your doctor’s phone numbers with you at all times. Make sure you know what number to call during your doctor’s office hours, as well as after hours.

What Can I Do to Protect Myself from an Infection?

Photo of a man with a thermometer and an ice pack.
Take your temperature any time you feel warm, flushed, chilled, or not well. Call your doctor right away if you have a temperature of 100.4ºF (38ºC) or higher.
Photo of a person washing hands.
Many diseases are spread by not cleaning your hands, which is especially dangerous when you’re getting chemotherapy treatment. Wash your hands often.
Photo of a man who has a fever.
Infection during chemotherapy can lead to hospitalization or death. Call your doctor right away if you notice any of the signs and symptoms of an infection.
Caregiver putting her hand on the head of a cancer patient who has fever.
Your doctor or nurse will let you know exactly when your white blood cell count is likely to be at its lowest. You should carefully watch for signs and symptoms of infection during this time.
Page last reviewed: November 10, 2020