In this episode, we review influenza, a highly contagious viral respiratory infection caused primarily by influenza A and B viruses, transmitted through respiratory droplets and capable of producing significant seasonal outbreaks. We discuss important risk factors for severe illness, including young children, older adults, pregnancy, immunosuppression, and underlying chronic medical conditions, along with the classic presentation of abrupt fever, chills, myalgias, fatigue, headache, cough, sore throat, and rhinorrhea. The segment also covers the diagnostic approach, emphasizing clinical recognition, rapid influenza diagnostic testing, and molecular testing with PCR, along with treatment strategies involving supportive care, hydration, fever management, and antiviral therapy with oseltamivir, particularly when initiated early in the course of illness. We finish with high-yield clinical pearls highlighting the importance of annual influenza vaccination, recognizing patients at increased risk for severe complications, initiating timely antiviral treatment, and monitoring for complications such as pneumonia, otitis media, myositis, encephalitis, and Guillain-Barré syndrome. References Bushardt RL, Colomb-Lippa DM, Klinger AM, Reed H. The JAAPA QRS Review for PAs: Study Plan and Guide for PANCE and PANRE. 1st ed. LWW; 2021. ISBN: 9781975143817 Neuzil KM. Influenza. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J, Holland SM, Langford CA. eds. Harrison's Principles of Internal Medicine, 22nd Edition. McGraw-Hill; 2025. Accessed March 11, 2026. Clinical practice guidelines for influenza. World Health Organization; 2024 Influenza, Seasonal. In: Papadakis MA, Rabow MW, McQuaid KR. eds. Quick Medical Diagnosis & Treatment 2026. McGraw Hill; 2027. Accessed March 16, 2026