Via The Lancet: Ebola and the social media. The abstract:
In October 2014, during heightened news coverage about cases of Ebola in the USA, anecdotal observations suggested that many Americans were anxious about Ebola. Given the negligible risk of infection, their anxiety was arguably driven by perceived rather than actual risk. Exaggeration or reassurance from the media can inflame or subdue people's perceived risk of Ebola infection. Fear can also be acquired by observation of other people's experiences, as expressed on social media. Thus, social media amplified fear about the imported Ebola case.