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(THE CONVERSATION) Editor’s note: This year, Australia suffered a record number of flu infections. This has some experts concerned that the U.S. will suffer a harsh flu season as well. Irena Kenneley, associate professor of nursing at Case Western Reserve University, explains what the news means and why it’s important for Americans to receive their annual flu vaccine.

1. When exactly is flu season, anyway?The timing of peak activity varies from year to year. Peak influenza activity...