Pneumonia and influenza, long considered scourges of old age, are among the most common health problems that confront people in their later years. Pneumonia and influenza are infections that are often far more serious in older people. Frail older people are at greatest risk. Pneumonia, for example, used to be called "the old man's friend," a quick way to death for an older person whose health was failing. Today, doctors try to prevent pneumonia and influenza and generally treat them aggressively—and successfully—in all but the most ill people.