Almost 17 million people in the United States are living as cancer survivors, according to the American Cancer Society. The organization also estimates that there will be about 1.9 million new cancer diagnoses in 2022.

Cancer and its treatment can have many effects on your body, one of which can be a weakened immune system. But are all people who’ve had cancer immunocompromised? Not necessarily.

In this article, we break down what it means to be immunocompromised, what can cause people with cancer to become immunocompromised, and the challenges associated with a weakened immune system. Keep reading to learn more.

People who are immunocompromised have a weakened immune system. This means that their immune system is less able to respond effectively to infections and other diseases.

A 2016 study analyzed the results of a 2013 health survey of adults in the United States. Based on their analysis, researchers estimated that 2.7% of adults in the United States were immunocompromised.

Some, but not all, people who have had cancer can have a weakened immune system. But what exactly does this mean? Are there different degrees of being immunocompromised?

There’s no hard and fast rule dividing up what makes someone slightly immunocompromised or moderately to severely immunocompromised. However, a good marker to look at is something called a neutrophil count.

Neutrophils are white blood cells (WBCs) that are vital in responding to infections. Their levels can be measured in the blood using a simple blood draw.

The ACS notes that you’re at an increased risk of infection when neutrophil levels are below 1,000 cells per microliter. This is called neutropenia. Your risk increases even more when neutrophil levels drop below 500 cells per microliter.

If you have cancer, you can become immunocompromised due to the effects of the cancer, the effects of your treatment, or both.

Some cancers can directly impact the way that the immune system works. Examples of such cancers include:

These cancers all affect blood cells, which are made in your bone marrow. When cancer cells are present in the bone marrow, they can crowd out healthy blood cells, including WBCs, and reduce their numbers.

A variety of cancer treatments can also weaken the immune system. These include:

  • Chemotherapy: Chemotherapy targets fast-growing cells, including healthy blood cells, such as WBCs, in the bone marrow. It’s the cancer treatment that most commonly causes a weakened immune system.
  • Radiation therapy: Radiation therapy can also lower WBC counts. However, it’s often only directed at one part of the body and is therefore less likely to impact the immune system in a large way.
  • Immunotherapy: Immunotherapy aims to help your immune system response to cancer. However, because this treatment alters how the immune system works, some types of immunotherapy may boost your infection risk.
  • Stem cell transplant: Stem cell transplants aim to reestablish a healthy bone marrow. One of the steps of this is to use high dose chemotherapy or radiation to kill cancer cells, which also kills healthy blood cells in the bone marrow, including WBCs. This increases infection risk.
  • Surgery: Surgery itself is hard on your body and generally weakens your immune system. Some types of surgery can also directly affect your immune system. An example is spleen removal, as the spleen both stores and filters your blood cells, including WBCs.

People who are immunocompromised are at an increased risk of contracting infections. These can include infections with:

Not only are immunocompromised people at a higher risk of getting an infection, but these infections can be much more severe than they would be in a healthy person. This is because the immune system cannot respond as effectively to the infection.

There are several things that you can do to help manage the infection risks that are associated with being immunocompromised. These include:

  • avoiding contact with people who are currently sick until they’ve recovered
  • washing your hands frequently with soap and water
  • regularly sanitizing high-touch surfaces in your home, such as doorknobs, light switches, and faucet handles
  • wearing a well-fitting mask when you’re out in public to protect against respiratory infections like COVID-19 and the flu
  • avoiding areas where infections can spread more easily, such as places that are crowded or poorly ventilated
  • receiving any recommended vaccinations as directed by your care team
  • washing all fresh produce thoroughly before eating
  • cooking all foods to at least the safe minimum cooking temperature
  • avoiding the consumption of raw or unpasteurized foods
  • being careful with activities that involve sharps, such as shaving and preparing food, and cleaning any cuts or nicks that happen right away
  • using care or asking for help when cleaning up after your pets

It’s also important to talk with your care team about ways to manage being immunocompromised. They can make more personalized recommendations based on your specific health situation.

Seek medical help if you develop signs of an infection

Always contact your care team promptly if you do develop symptoms of an infection. Some signs to look out for can include:

  • fever
  • chills
  • cough
  • headache
  • skin rash
  • areas that are painful, red, or swollen

Coping with a weakened immune system can be stressful. However, there are some steps that you can take to help boost your immune system after cancer.

Eating well

Eating a balanced diet can help to keep your immune system in tip-top shape. According to the Centers for Disease Control and Prevention (CDC), eating well means focusing on:

They also note that it’s important to limit other types of foods, such as those that have high levels of:

Exercising regularly

Exercise can have positive effects on your immune system. A 2020 review notes that exercise, especially moderate exercise, can improve immune activity and reduce illness risk.

Not sure how to get started? Talk with your care team about an exercise routine that would be appropriate for you.

Improving sleep quality

Sleep quality can impact your immune system. According to a 2021 review, sleep supports the immune system, and getting less sleep can increase the risk of infection and chronic inflammation. Examples of ways to promote good sleep are:

  • setting a sleeping and waking schedule that you can stick to
  • having a nighttime routine to help you relax before bed
  • reducing your intake of caffeine and alcohol in the hours before you go to bed
  • making sure your sleeping space is dark, quiet, and a comfortable temperature

Reducing stress

Research has found that stress can lead to immune system dysregulation, which can increase your risk for infection and elevate inflammation in your body. So, try to find ways to lower stress in your daily life, such as:

  • spending quality time with your support network
  • engaging in a hobby that you enjoy
  • doing yoga
  • trying out meditation
  • listening to calming music

Cutting back on alcohol

Chronic, heavy alcohol use can lead to an increased vulnerability to infections, according to a 2016 review. Because of this, aim to drink only in moderation or not at all. The American Cancer Society recommends that cancer survivors not consume any alcohol.

Quitting smoking

The CDC notes that smoking can harm the immune system and decrease its ability to respond to infections. If you smoke, work with your doctor to develop a quit plan.

Are people with chronic conditions considered immunocompromised?

Sometimes. A few examples of chronic health conditions where a person can be immunocompromised include:

Will my immune system be weakened forever after surviving cancer?

Not necessarily. Immune function can slowly return to normal levels over time. However, this may take longer than previously thought.

A 2016 study of people who received chemotherapy for breast cancer found that levels of certain immune cells still remain significantly low 9 months after treatment.

Are cancer survivors at high risk of severe COVID-19?

Yes. Research from 2021 found that having had a cancer diagnosis was associated with a higher risk of hospitalization and death due to COVID-19. However, this effect was higher in those that still had active cancer.

Is it safe for a cancer survivor to receive a COVID-19 vaccine or booster?

Yes, the COVID-19 vaccine, including the booster, is safe for cancer survivors. The National Comprehensive Cancer Network recommends that people with a history of cancer be vaccinated against COVID-19 as soon as possible.

The FDA also approved Evusheld as a prophylactic for adults who are immunocompromised and who may not be able to mount an immune response to the COVID-19 vaccination.

Is it safe for cancer survivors to receive live vaccines?

For most survivors, yes, at some point. However, you may need to wait 3 to 6 months based on the type of treatment you had and when you completed it.

Because they can replicate in the body, live vaccines can cause serious problems in people with a weakened immune system. As such, your doctor will want to assess your immune health before administering a live vaccine.

Some cancer survivors can be immunocompromised. This means that your immune system is weakened and cannot respond to infections as effectively.

Because of this, immunocompromised people are at a higher risk of contracting infections and having more severe illnesses due to them. It’s important to take steps to reduce infection risk while you’re immunocompromised.

It’s possible that your immune function will slowly return to normal as time passes after your treatment. In the meantime, there are many things that you can do to help to boost your immune system.