COVID-19 and Cancer
For some people with cancer and weak immune systems, COVID-19 can lead to serious illness. It's important for people with cancer to get the COVID-19 vaccine to help prevent infection. COVID-19 vaccines do not contain live viruses, so they are safe for people with weakened immune systems.
Learn about COVID-19, how the virus can affect people with cancer, how to protect yourself and loved ones, and what to know about vaccines and staying safe.
What is COVID-19?
COVID-19 (coronavirus disease 2019) is the name of the illness caused by a type of virus called a coronavirus. Several types of coronaviruses can infect humans. Some can cause more serious illnesses than others. The coronavirus that causes COVID-19 is SARS-CoV-2.
Both adults and children can get COVID-19, even more than once. Anyone with COVID-19 can spread it, even if they don’t have any symptoms.
COVID-19 variants
Over time, the virus that causes COVID-19 can mutate. This results in new variants of the virus. New variants might spread more easily or cause slightly different symptoms. Older vaccines might not protect against new variants. The COVID-19 vaccines have been updated each year to help them be as effective as possible.
Symptoms of COVID-19
People with COVID-19 can have a wide range of symptoms, ranging from mild to severe. Some people might have no symptoms at all.
Acute COVID-19 infection
An acute infection happens within a short amount of time after a person is exposed to COVID-19. Most people start to feel sick about 3 to 4 days later. But some signs can show up as late as 14 days after.
The most common symptoms of COVID-19 are:
- Fever or chills
- Cough
- Shortness of breath
- Muscle aches and pains
- Sore throat
- Loss of smell or taste
- Stuffy or runny nose
- Feeling very tired
- Headache
- Diarrhea
- Nausea or vomiting
If you have cancer and have any of the above symptoms that get worse or don’t go away, contact your cancer care team. If you are being treated for cancer, ask your care team if you need to delay any treatment based on your symptoms.
Serious signs and symptoms
COVID-19 can also sometimes cause serious signs and symptoms that need medical attention right away:
- Trouble breathing
- Constant pain or heaviness in the chest
- Confusion or being hard to wake up
- Pale, gray, or blue-colored skin, lips, or nails, depending on skin tone
Whether you have cancer or not, if you have any of these serious symptoms, get medical attention right away.
Long COVID
Some people who’ve had COVID-19 might have long-term effects. These might be called post-COVID conditions, long COVID, chronic COVID, or long-haul COVID. People who have been gotten COVID-19 more than once have a higher risk of developing long COVID.
A person with long COVID can continue to have some of their initial symptoms last longer than usual. Some symptoms might get better or go away completely, while others remain a problem for weeks, months, or even longer.
Some common symptoms of long COVID include:
- Extreme tiredness that affects your daily life
- Symptoms that worsen after mental or physical effort
- Trouble thinking or concentrating
- Shortness of breath
- Diarrhea
People who get the COVID-19 vaccine are less likely to get long COVID than people who do not, but anyone can still get it.
If you have cancer and have long COVID, be sure to keep your cancer care team updated on your symptoms. Many cancer treatments can have some of the same side effects as long COVID.
For the latest on COVID-19 symptoms, variants, and long COVID, visit the US Centers for Disease Control and Prevention (CDC) website.
COVID-19 in people with cancer
Some cancers and their treatments can weaken your immune system. When this happens, having had COVID-19 or the COVID-19 vaccine might not be enough to protect you from future infections.
Research shows:
- Cancer itself and its treatments can increase a person’s risk of getting COVID-19.
- Some people with cancer have higher risks of having severe symptoms of COVID‑19.
- Some people with cancer have a higher risk of hospital admission. This also includes needing care in the intensive care unit (ICU) and mechanical ventilation (being on a ventilator) to help treat COVID-19 and its symptoms.
The risk is lower if your treatment was several years in the past. But the situation for each person is different.
It’s important to get the COVID-19 vaccine to lower your chance of getting sick. If you get sick, get care fast.
Which people with cancer are at higher risk from COVID-19?
A few risk factors for having more serious signs and symptoms include:
- Having a weak immune system
- Having excess body weight (overweight or obesity)
- Smoking, now or in the past
- Having certain types of cancer, such as leukemia, lymphoma, or lung cancer
- Getting cancer treatment now or in the past year
- Getting chemotherapy (chemo), long courses of corticosteroids (steroids), certain types of immunotherapy, or a stem cell or bone marrow transplant
- Living with lung cancer, because the virus that causes COVID-19 often targets the respiratory system
- Needing frequent medical appointments, which can increase their risk of being exposed to the virus that causes COVID-19
Each person’s situation is different. It's important that people who’ve had cancer talk with a doctor who understands their situation and medical history.
How can I lower my risk of getting COVID-19?
If you have cancer, there are several things you can do to help lower your risk of being infected with the virus that causes COVID-19. Talk to your cancer care team about which precautions are right for you. Their recommendations will depend on whether you have a weak immune system or other risk factors for severe COVID-19.
Vaccines are one of the most important ways to help protect against COVID-19. Most cancer doctors recommend COVID-19 vaccines for people with cancer. But if your cancer treatment weakens or wipes out your immune system, it might make sense to postpone getting the vaccine for a while.
If you’re being treated for cancer, ask your doctor about the best time for you to get the vaccine.
For more on the COVID-19 vaccine, visit the CDC website.
Some people with a weak immune system do not get enough protection from the COVID-19 vaccine. For some of these people, a medicine called pemivibart (Pemgarda) can help lower the risk of getting COVID-19.
This medicine is not a substitute for the vaccine. If you can get the vaccine, you should still get it. Pemivibart is given at least 2 weeks after a COVID-19 vaccine dose. This medicine is given into a vein (IV), about once every 3 months.
This medicine does not work against every form of the COVID-19 virus. As the virus changes, the medicine might not work as well. Because of this, it is not always the right choice. Talk to your doctor to find out whether pemivibart is a good option for you.
Even if you’re up to date with vaccines, take preventive medicines, or have had COVID-19 in the past, you can still get COVID-19.
Other things you can do to help lower your risk of getting COVID-19 might include:
- Avoiding crowded indoor spaces
- Avoiding close contact with people who are sick
- Wearing a mask when out in public
- Washing your hands often with soap and water
Learn more ways to protect yourself and others in Infections in People with Cancer.
Information on COVID-19 from other organizations
The following organizations might also offer helpful information. The American Cancer Society is not affiliated with or responsible for these resources.
- Written by
- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
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Last Revised: November 9, 2026
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