Most individuals who catch the flu recover in a few days and it usually lasts no more than two weeks. Sinus and ear infections are examples of mild flu consequences but there are also potentially fatal complications that can arise such as pneumonia or tissue inflammation.
A flu virus infection of the respiratory tract can cause a severe inflammatory reaction in the body, leading to sepsis, the body's potentially fatal response to infection. Flu can exacerbate existing medical conditions and worsen the situation if someone has asthma or heart disease.