When Health Information Meets Social Media: Exploring Virality on Sina Weibo.

This study explored the impacts social media bring about on health communication. The impacts involved four factors: authority, privacy, evidence, and incentive appeals. They were adopted to predict virality of health messages on Sina Weibo in terms of retweeting, endorsing, and replying. A quantitative content analysis was conducted with a two-stage probability sample of 1,261 messages from 34 accounts. The results illustrated two modes Weibo users employed to process health information. The heuristic mode was used for retweeting that was sensitive to public messages, negative appeals, and nonprofessional authority. The systematic mode was used for endorsing and replying that were sensitive to private messages, positive appeals, and both professional and nonprofessional authorities.