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Ana Velez, MD, FACP, Infectious Diseases and Internal Medicine, associate professor at the University of South Florida, answers five questions about the flu vaccine.

1. Why is the flu a major concern for cancer patients?
The flu virus is a very common cold virus circulating in the fall and winter time and is also one of the respiratory viruses with the highest mortality rate. It is of particular concern for cancer patients because certain cancers can affect the immune system. Some chemotherapy treatments can also affect the body’s immune response. In patients who have cancer and are immunosuppressed, the flu can have more severe complications including respiratory failure and secondary bacterial infections. In addition, they can have a more prolonged course of illness than in healthy individuals with healthy immune systems.

2. Is the flu vaccine recommended for most people who are currently diagnosed with and undergoing treatment for cancer? Is the injectable or nasal mist recommended?
The flu vaccine that is recommended this year is the injectable form. The nasal spray version of the vaccine, which is a live attenuated virus, is not recommended for anyone this year. As far as the injectable vaccine, it is an inactivated form of the vaccine, so it is safe for immunosuppressed patients. These individuals should receive the flu vaccine every year. Family members or individuals living with a cancer patient should also receive the vaccine. The only individuals who should not receive the vaccine are those who have ever had Guillain-Barre Syndrome and those who experienced severe anaphylaxis or allergic reactions with past flu vaccines. In some instances, these individuals may still receive some special types of vaccines if they can be monitored in a healthcare setting and visit an allergy doctor who can do specialized testing.

3. Is the flu vaccine still important for patients who have been cleared of cancer and have no evidence of disease?
Actually, the flu vaccine is important for all of us, with or without cancer, immunocompetent or immunosuppressed. If we contract the flu and get no complications from it, we can still pass it to other people with risk factors for severe disease such as pregnant women, small children, and those who are immunocompromised, among others. If you are a cancer survivor and you have no issues with the immune system, you should still receive the annual vaccine.

4. Can I really get the flu from the flu vaccine?
There is no live flu virus in the flu shot. The vaccine cannot cause the flu. There are some side effects from the vaccine, such as local-site reactions and mild muscle pain – but those don’t last for long. Having those minor side effects is nothing compared the severe complications you can get from the actual flu. However, there are other cold viruses circulating around during fall and winter time that can also cause cold and have similar flu symptoms. Some of them can also have serious complications but are not influenza. Unfortunately, there is not yet a vaccine for those viruses.

5. Will the flu vaccine still be effective if I am immunocompromised?
If your immune system is weak, you should still get the flu vaccine. In that case, the vaccine may not be 100 percent protective, because you need to have a good immune system in order to have a good response to the vaccine. Unfortunately, you can still contract the flu even if you had the vaccine, this may happen because your immune response was not strong enough to develop an immune reaction against the flu. In addition, there are many strains of the flu. The vaccine changes year to year based on previous circulating types of flu, and as a consequence, the efficiency of the vaccine is better some years than others. However, it’s better to have some protection than none. If you can do something to prevent the flu and it’s in your hands you should do it.

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