Seasonal flu, often called the influenza, is a contagious respiratory illness caused by influenza viruses. It typically spreads during the colder months and can lead to symptoms like fever, cough, sore throat, and body aches. Most people recover within a week or two, but it can be more serious for certain groups, such as the elderly or those with weakened immune systems. To protect against seasonal flu, getting the annual flu vaccine is recommended. This vaccine helps the body build immunity against the most common strains of the virus. Practicing good hygiene, like washing hands frequently, can also help prevent the spread of the flu.