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Influenza (Flu) Complications

British Columbia Specific Information

Influenza is an infection of the respiratory system caused by the influenza virus. Symptoms vary from mild to severe and can include fever, headache, runny nose, sore throat or cough. The influenza vaccines protect against the viruses that cause influenza. To learn more about the influenza vaccines, and to access influenza-related information from your health authority, visit our Influenza (Flu) Season health feature.

The symptoms of flu are similar to other respiratory illnesses including the common cold and COVID-19. Use the BC COVID-19 Self-Assessment Tool to find out if you or your family members need further assessment or testing for COVID-19. To learn more about the coronavirus, symptoms, how it spreads and prevention visit the Coronavirus (COVID-19) health feature.

Overview

Although most cases of influenza (flu) get better without causing other problems, complications sometimes develop.

Possible problems from the flu include:

  • Pneumonia, which is an infection of the lungs. It rarely causes death in young, healthy people. But it can often be life-threatening in older adults, people who have other diseases, and pregnant women.
  • Bronchiolitis. This is an inflammation of the small air passages. It affects infants and is the leading cause of serious lower respiratory illness.
  • Sinusitis. This means the mucous membranes that line the inside of the nose and facial sinuses become infected and inflamed.
  • Croup. Croup is a swelling or blockage in the windpipe. It causes hoarseness, a barking cough, a high-pitched sound when breathing in, and trouble breathing.
  • Chronic obstructive pulmonary disease (COPD) symptoms may get worse.
  • Inflammation of the heart muscle, the sac around the heart, or other muscles.

Credits

Current as of: October 31, 2022

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Christine Hahn MD - Epidemiology