According to the Centers for Disease Control, respiratory syncytial virus (RSV) causes about 60,000 hospitalizations of children aged 0 to four, and nearly 200,000 hospitalizations and 14,000 deaths among adults 65 and older. However, there are virtually no vaccines or treatments for these infections. In a new study, researchers found evidence that the cytokine, Interleukin 27 (IL-27), may be the key to fighting and treating these infections.