People with weakened immune systems due to cancer are at increased risk of severe complications from the influenza virus, according to experts. Flu-related complications are known to be highest in very young people and the elderly.

“The flu shot is recommended annually for cancer patients, as it is the most effective way to prevent influenza and its complications,” said Mollie deShazo, MD, associate professor of medicine in the Division of Hematology and Oncology and medical director of University of Alabama at Birmingham Inpatient Oncology. “The flu vaccine significantly lowers the risk of acquiring the flu; it is not 100% effective, but it is the best tool we have.”

Flu activity in the United States is low, even after increasing slightly in recent weeks, according to the Centers for Disease Control and Prevention. However, more activity is expected, and people who have not had a flu vaccine this year are advised to do so.

“It takes up to 2 weeks to build immunity after a flu shot, but you can benefit even if you get the vaccine after the flu has arrived in your community,” deShazo said.

The flu shot—not the mist—is safe and is recommended for people with cancer.

“Patients with cancer or who are undergoing chemotherapy should not get the flu mist because it contains live flu virus and could lead to complications in immunocompromised patients,” deShazo said, adding:

• Cancer patients should avoid contact with anyone suspected of having the flu.

• It is prudent to wash hands often and thoroughly with soap and water and avoid touching eyes, nose, or mouth whenever possible.

• It is recommended that all caregivers and family members of cancer patients also get the flu vaccine to protect their loved ones.

Once one is cancer-free, his or her risk lessens.

“The longer patients are cancer-free, the lower their influenza complication risk, until it is no more than the risk of those who’ve never had the disease,” deShazo said.