During the 2013 outbreak of human infections of avian influenza A(H7N9), the Centers for Disease Control and Prevention (CDC) used official data released by the World Health Organization (WHO) and the Chinese government to keep United States public health officials informed of updates of the outbreak.1 The Chinese central government released official avian influenza A(H7N9) data via its web sites (e.g. National Health and Family Planning Commission2), their official news agency (Xinhua News Agency) and their official newspapers (e.g. People’s Daily, Beijing). In addition, official avian influenza A(H7N9) information was released by Chinese provincial and municipal governments such as Shanghai Municipal Bureau of Health,3 Jiangsu Department of Health4 and Zhejiang Department of Health.5 Prior studies have discussed the role of social media in the early detection of disease outbreaks6–9 and the facilitation of community-level discussion.10 In this perspective, we focus on the use of social media by public health agencies to disseminate and obtain official outbreak information during a public health emergency response.