Swine FLU Diagnosis and Prognosis: The diagnosis of swine flu mostly depends on the signs and a symptom it produces and based on this the analysis is done to identify the virus. Correct and confirmed diagnosis is needed to control the spread of the disease. Swine flu (H1N1) prognosis is good in most people. Rarely swine flu can cause severe illness or death due to complications such as pneumonia. Read articles on how swine flu is diagnosed and about swine flu prognosis.