Influenza, most commonly referred to as the “flu” is a contagious viral infection caused primarily by the influenza virus A or B. It generally affects the nose, throat, bronchi, and lungs (i.e. upper respiratory organs) but other organs such as the heart, brain, and muscles can also get affected in severe cases.
The occurrence of influenza is worldwide showing pandemic, epidemic, or seasonal patterns. Epidemics of flu happen annually during autumn and winter in temperate areas and produce significant mortality and morbidity each year.
The virus is transmitted from person to person with respiratory droplets produced when the patient coughs or sneezes within close contact (<1 m). Individuals usually recover after a few days, but influenza can give rise to complications, especially in high-risk groups like pregnant women, individuals with an underlying immunodeficiency state, adults older than 65 years of age, children below 5 years, and individuals with chronic diseases like asthma, heart and kidney conditions.
The symptoms of flu include high fever, body ache, headache, severe malaise, dry cough, sore throat, and runny nose. It should be differentiated from the common cold by clinical presentations. Flu also shares some of its symptoms with COVID -19 infection. One cannot tell the difference between flu and COVID-19 just by looking at the symptoms, hence, testing is needed to confirm the diagnosis. Testing is also important as it can determine if someone is suffering from both flu and COVID-19 at the same time.
Treatment of flu involves relieving the symptoms and in some cases, the use of antiviral drugs is also required. Though the annual influenza vaccine isn't 100% effective, it's still the best defense against the flu.
