Seasonal Influenza: A Narrative Review of Epidemiology, Clinical Features, and Preventive Strategies

Seasonal influenza, caused by influenza A and B viruses, remains a significant global respiratory illness, particularly during winter epidemics. Transmission occurs mainly through respiratory droplets containing high viral loads expelled during coughing or sneezing. This review aims to summarize recent developments in the clinical features, prevention, and evolving treatment strategies for seasonal influenza. Relevant literature from global and regional (including South Asian) sources was reviewed to identify updates in influenza epidemiology, diagnosis, vaccination, and antiviral therapy. Influenza typically presents with sudden-onset fever, myalgia, headache, and malaise, accompanied by upper respiratory tract symptoms such as sore throat, rhinorrhea, and nonproductive cough. While most healthy adults clear the virus within five days, children, the elderly, and immunocompromised individuals may shed it for up to 10 days or longer. Severe complications involving the brain, heart, or lungs may lead to hospitalization. Annual vaccination remains the most effective preventive strategy, while early antiviral therapy, initiated within 48 hours of symptom onset, reduces morbidity and mortality. Despite advances in prevention and management, the global burden of influenza persists. Strengthening surveillance, improving vaccine coverage, and promoting timely antiviral use are essential to reduce seasonal influenza-related morbidity and mortality.