all of boston's world famous hospitals are operating in overdrive. at mass general, boston's biggest hospital in the center of the city, there were 72 confirmed cases of the flu last week alone. shane has a temperature of 104 degrees. he's already been out of work for four days. >> it's costing me financially and lost time, and maybe my job. >> you ought to be wearing the mask when you're in public and keep yourself away from people. wash your hands all the time. >> reporter: four miles away back at children's hospital, cassie now needs chest x-rays, her lungs full of mucous. just down the hall is 4-month-old casen page, born with congenital heart disease. for children like casen, the flu can be a matter of life and death. and at brigham hospital, doctors pay close attention to elderly patients, who are also at