As medical improvements have raised initial survival rates, more patients are progressing to the latter stages, leaving doctors to deal with nosocomial and other secondary infections. According to an autopsy research, many patients who die of sepsis in the ICU had indications of immune suppression. This evidence was presented in 2004 at the 38th Annual Meeting of the Society of Critical Care Medicine and has been confirmed by other studies. The autopsies revealed that 80% of people who died from septic shock showed signs that their immune systems were impaired. The researchers also found that these individuals' lymph nodes were larger than normal, suggesting they were producing more antibodies. However, the numbers were low-level compared with healthy people, indicating that the immunosuppression was happening because bacteria were escaping detection by the few remaining immune cells. People who have survived sepsis report difficulties with immunity for up to one year after discharge from the hospital. They are more likely to develop infections that can't be fought with antibiotics, such as pneumonia or urinary tract infections. In addition, data from animal models suggest that sepsis may cause long-term changes in the brain that could lead to increased risk for neurodegenerative diseases later in life. Further research is needed to confirm this connection in humans.