
Out of the 50 state public health departments in the U.S., 26 had Twitter accounts in 2011, according to a study published in the journal BMC Public Health.
The study found that 17 state public health departments had Facebook accounts in 2011, 13 had a YouTube channel, four had a Flickr account and one had a blog,
The study is based on a non-experimental, cross-sectional analysis of state public health departments' use of social media websites conducted between February and March 2011.
Source: BMC Public Health, "Adoption and Use of Social Media Among Public Health Departments"