Are you at risk?

People with certain chronic (long-term) medical conditions are at risk for flu complications:

Heart disease

People with heart disease, such as congenital heart disease, coronary artery disease, or congestive heart failure (CHF), are at risk of flu complications. In fact, people with heart disease are more likely to die of the flu or its complications than people with any other chronic medical condition. The flu can also make heart disease worse. It is not known exactly why this happens.

Lung disease

The flu and lung disease both put stress on the lungs. Therefore, people with lung disease, such as asthma, cystic fibrosis, or chronic obstructive pulmonary disorder (COPD) are at risk of flu complications. The flu and its complications can also make the symptoms of lung disease worse.


People with diabetes can have a harder time fighting off infections, and most flu complications are caused by infections. Plus, people with diabetes are at a higher risk of other medical conditions that can increase the risk of flu complications, such as heart and kidney disease. Therefore, people with diabetes are at risk of flu complications.

Weakened immune system

The immune system helps your body fight infections. A weakened immune system can put someone at risk of flu complications by making it harder to fight the flu and other infections that may occur as complications of the flu (such as pneumonia). The flu also tends to last longer in people with weakened immune systems.

The immune system can become weakened by:

  • HIV/AIDS, an infection that attacks the immune system
  • cancer
  • medications for certain conditions, such as:
    • organ transplants: e.g., steroids, medications that suppress the immune system to prevent it from rejecting the organ (e.g., cyclosporine, tacrolimus, mycophenolate mofetil)
    • cancer: e.g., chemotherapy
    • certain types of arthritis, such as rheumatoid arthritis: e.g., steroids, biologics (medications that modify the response of the immune system, such as adalimumab or infliximab), medications that suppress the immune system to prevent it from attacking the body (e.g., methotrexate, azathioprine)
    • Crohn's disease: e.g., steroids, biologics (see above), or medications to suppress the immune system

Other conditions

Other medical conditions that can increase the risk of flu complications include:

  • kidney or liver problems
  • neurological problems, such as brain disorders, spinal cord injury, nerve disorders, cerebral palsy, epilepsy, stroke, developmental delay, and muscular dystrophy
  • blood disorders, such as sickle cell anemia
  • metabolic disorders, such as mitochondrial disorders and inherited metabolic disorders

Reducing your risk of flu complications

If you have a chronic medical condition, try these tips to reduce your risk of flu complications:

  • Take steps to prevent the flu. Your doctor may recommend a flu shot (to reduce the risk of the flu) and a pneumococcal vaccine (to reduce the risk of pneumonia, a common flu complication).
  • If you are at risk of flu complications (see above) and have symptoms of the flu, see your doctor as soon as possible (find the flu clinic nearest to you). Use the doctor discussion guide to help you prepare for your visit. Your doctor may prescribe an antiviral medication, which can reduce the risk of complications, reduce symptoms, and shorten the length of illness if taken within 48 hours of the start of your symptoms.
  • If you are diagnosed with the flu, follow your doctor's instructions for flu treatment. If your doctor prescribes an antiviral medication, have the prescription filled as soon as possible, and keep taking the medication for as long as your doctor recommends to complete the full course of treatment. Follow your doctor's instructions for managing your chronic medical conditions and continue your medications for these conditions as directed by your doctor. Also follow any special instructions your doctor may give you about managing your medical condition during an illness such as the flu.

To learn more about your risk of flu complications, use our tool "Are you at risk of flu complications?" and talk to your doctor.