Archdiocese of Chicago

The H1N1 Influenza
:: What You Need To Know

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H1N1
What are the signs and symptoms of H1N1?

Influenza Symptoms Influenza (also known as the flu) is a contagious respiratory illness caused by flu viruses. It can cause mild to severe illness, and at times can lead to death. The flu is different from a cold. The flu usually comes on suddenly and may include these symptoms:

  • Fever (usually high)
  • Headache
  • Extreme tiredness
  • Dry cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle aches
  • Stomach symptoms, such as nausea, vomiting, and diarrhea, also can occur but are more common in children than adults

These symptoms are usually referred to as "flu-like symptoms."