Social versus independent interest in 'bird flu' and 'swine flu'.

The explosion of interest in H1N1, more popularly called 'swine flu', across the world, from late April to early May 2009, exemplified how information transmission in modern online society can affect the spread of the disease itself. A simple but effective model based on cultural evolutionary theory can characterise in such data the effective degree of social transmission versus independent decision. In a novel approach that applies this model to Google Trends search data, we find significant differences in social transmission of the exact phrase 'swine flu' in 2009, compared with 'bird flu' in 2005. The methodology can thus inform policies for addressing public awareness of health issues, which can be more effective with knowledge of how the information is being spread or learned.