The Fogg theory of mass interpersonal communication suggests that social media has the ability to combine the credibility of interpersonal persuasion with mass media, resulting in a desired attitude or behavior among a large group of people. Although social media can be a very effective way of communicating health recommendations, they can also be used to spread incorrect information (a.k.a., fake news). Content analyses of social media show a mix of positive and negative messaging regarding vaccination against HPV, and sentiment may vary by social media site. Positive messages are more likely to appeal to logic, citing facts and statistics, whereas negative messages are more likely to use personal stories to appeal to emotions. An ecologic study has shown a correlation between the predominant HPV vaccine sentiment in a state and statewide HPV vaccine coverage, suggesting social media messaging has the ability to influence HPV vaccination decisions.