Infections in People With Cancer

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Vaccines during cancer treatment

People with weak immune systems can get some vaccines, but they should not get vaccines that contain live virus. Fatal infections have been caused by giving live-virus polio, measles, and smallpox vaccines to people with weak immune function.

It’s generally recommended that vaccines not be given during chemo or radiation treatments — the only exception to this is the flu shot. This is because vaccines need an immune system response to work, and you may not get an adequate response during cancer treatment.

In many cases, live-virus vaccines can be given at least 3 months after all immune-suppressing treatment has stopped. But this time varies and you should talk to your doctor before you or anyone you live with or spend a lot of time with gets vaccinated with a live virus.

Even when your immune system is weak, some preventive immunizations can be very helpful. Your doctor should tell you about any vaccines that might help you, such as certain ones that may be recommended after bone marrow or stem cell transplant. But it’s important to know which vaccines are safe for people with weak immune systems. We will talk about the most common vaccines here.

    Be sure to talk to your cancer doctor before you or anyone you spend a lot of time with gets any vaccines.

Flu shots

The flu shot is given to reduce your risk of getting influenza (the flu). Since the flu raises your risk of pneumonia (lung infection), avoiding the flu lowers that risk. The flu shot may be given at least 2 weeks before chemo or between chemo cycles. It can be given 6 months after a bone marrow or stem cell transplant, and every year after that.

Flu-mist®, the nasal mist version of the flu vaccine, contains a weakened version of the live virus. People with cancer should NOT use the nasal mist flu vaccine. Family members of a person with cancer can safely get the nasal spray unless the patient is being cared for in a germ-protected area. For example, household members should not get the nasal mist vaccine if a family member has recently had a stem cell or bone marrow transplant.

For more information on this, see our document called Should I Get a Flu Shot?

Polio and smallpox

Polio vaccine: Children who have weak immune systems, as well as their siblings and others who live with them, only should get inactivated polio virus vaccines. Most doctors in the United States use only the inactivated polio vaccine, but you can ask to be sure. The older oral polio virus vaccine (which is taken by mouth) contains a live virus. People who get the live virus vaccine can pass the poliovirus on to people with weak immune systems.

Smallpox vaccine: In general, people with weakened immune systems should not get the smallpox vaccine. Household members of those with weak immune systems should not get it either. There are many other restrictions and exceptions on how this vaccine is used. To learn more about smallpox vaccination, see our document called Smallpox Vaccine and Cancer.


People who have very weak immune systems should not get the measles-mumps-rubella (MMR) vaccine because it contains live virus. But unlike the smallpox vaccine, it’s safe for other household members to get it.

After exposure to measles: If the person being treated for cancer is exposed to someone with measles, let the doctor know right away. Sometimes, measles immune globulin (a blood product that contains antibodies to the measles virus) can be given to help fight the measles infection before it starts.

Pneumococcus (pneumococcal pneumonia)

Your doctor may recommend one or more doses of the pneumococcal vaccine, depending on your age and health history. If you are to have your spleen removed, the vaccine will be given before surgery. Most adults with long-term health problems get the Pneumovax® (or PPV-23) vaccine. The vaccine can help people with weak immune systems fight off serious infections, such as pneumonia, caused by certain bacteria. Children and those with recent bone marrow transplants may get a different vaccine (called PCV or Prevnar 13) to help them fight this germ, although some may need the PPV-23 vaccine later.

Pneumococcus can cause serious infections that can invade the lungs, blood, or brain (meningitis). These infections can be life-threatening. People with chronic illness, including a weak immune system, can reduce their risk of this infection by getting the pneumococcal vaccine.

Varicella (chickenpox)

This is another live virus vaccine that’s given only to people with blood tests that do not show immunity to the varicella zoster virus (VZV). Varivax® is intended to prevent chickenpox in people who have never had it. But this vaccine should not be given to people while their immune systems are weak. It’s OK for household members of the person with weakened immunity to get the varicella vaccine.

After exposure to chickenpox: A person with weak immunity who has been exposed to someone with chickenpox should call the doctor right away. The patient may need VZV immune globulin (a blood product that contains antibodies to the VZV virus) to help fight the virus. It must be given within 72 hours of exposure. Cancer treatment may be stopped and restarted after the end of the VZV incubation period (the time it takes to see if you get sick, usually about 21 days). If a person with cancer has signs of VZV infection, the doctor may hold off on cancer treatment that causes immune suppression until scabs have formed.

Varicella zoster (shingles)

Zostavax® is a live virus vaccine that is given to prevent shingles (or make symptoms of shingles less severe). It’s used in adults age 60 and older who have had chickenpox. It’s not used in people whose immune systems are weak, including people being treated for cancer.

People who have had stem cell transplants must wait at least 2 years after the transplant to take this vaccine. And if you are on any drug that suppresses the immune system or you’re getting chemo or radiation treatments, you should not get Zostavax. Talk to your doctor before you or anyone in your household gets this vaccine.

See “Varicella zoster virus” under “Viruses” in the section called “What kinds of germs cause infections in people with cancer?” for more information about shingles.

Last Medical Review: 11/06/2013
Last Revised: 11/06/2013