The COVID-19 and flu vaccines are safe for cancer patients regardless of where you are in your course of treatment.

Story by: Norton Healthcare; Reviewed by John T. Hamm, M.D. on November 28, 2023

Both the flu shot and the COVID-19 vaccine are safe if you are a cancer patient, a cancer survivor or in the midst of chemotherapy, radiation therapy, immunotherapy or other course of treatment. The injectable vaccines do not contain live virus. The vaccines trigger an immune response using dead viruses.

The American Cancer Society emphasizes that having cancer or undergoing cancer treatment can compromise your immune system, making it crucial to prioritize vaccination. By getting vaccinated against influenza or COVID-19, you can significantly reduce the risk of developing severe complications. Vaccination also reduces the risk of spreading the flu virus and coronavirus, so it is important for people who live with or care for you.

Flu season runs from September through March, and the vaccine takes about two weeks to build up an immune response in your system. Getting vaccinated early in the season is best, but even if you’ve put it off, influenza vaccination can help protect you late in the season.

The flu vaccine is 40% to 60% effective at preventing the need for medical treatment for flu. Because the flu virus varies every season, the vaccine is reformulated each year. Some years it works better than others. The COVID-19 vaccine reduces hospitalization of adults who become infected by 62%.  

“Even if you catch the flu or COVID-19, vaccination helps. The vaccines can reduce the severity of the illness and reduce the chances that you develop serious complications like pneumonia, sepsis or inflammation of the heart, lungs, bronchial tubes, brain or muscle,” said John T. Hamm, M.D., a medical oncologist focusing on lung cancer with Norton Cancer Institute. “This is especially important if you are or have been a cancer patient.”

Dead versus live viruses

While the flu shot contains dead seasonal flu virus, the nasal spray vaccine contains weakened live virus. The live virus could be dangerous if you have a weakened immune system. Talk to your oncologist or other health care provider about which immunization is right for you.

If you have a blood cancer, like leukemia or lymphoma, you may have a weakened immune system. Some types of cancer treatment, such as chemotherapy, immunotherapy, radiation therapy or stem cell transplants can weaken your immune system.

Advance planning for your flu shot or treatment

When you get the flu shot, tell the medical provider about your cancer, your past and upcoming treatments before getting vaccinated. Also, let them know if you are allergic to eggs, which are often used in developing vaccines.

If you have cancer or are a cancer survivor, talk to your health care provider now about what to do if you get sick. Flu symptoms also can be a sign of a more serious infection, including COVID-19. Planning gives you guidelines about when to call your doctor or seek out treatment and how to get a prescription for flu antiviral medication if necessary. Talk to your medical provider about the RSV vaccine and pneumococcal vaccine as well.

Additional flu and COVID-19 prevention steps

• Wash your hands often.
• Avoid touching your face.
• Keep surfaces clean, especially those you touch often, such as counters, phones, and handles.
• Wear a mask in public if your doctor recommends it. 
• Stay away from people who are sick. If you feel sick, stay home. 
• Cover your mouth and nose if you cough or sneeze.