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Cause and Risk Factors
The flu results from infection with an influenza virus. In most cases, people infected with the flu recover without medical treatment within 2 weeks. Patients who have heart, lung (e.g., asthma), or kidney problems, diabetes, cancer, or HIV/AIDS have a higher risk for developing complications (e.g., pneumonia) from the flu. Young children under 2 years of age and people over the age of 65 also are at increased risk.

Other people who are at increased risk for developing...Read the full article