The proliferation of social media has allowed the antivaccine movement to become more influential than at any point in history. Earlier studies have demonstrated that social media platforms such as Pinterest and Twitter are filled with antivaccine information. The consumption of antivaccine social media content could negatively impact vaccine attitudes and consequently vaccine uptake. Furthermore, social media can indirectly influence the public by setting the agenda of traditional mass media in vaccine-related controversies. In some cases, social media platforms such as Twitter have even been weaponized to promote antivaccine messages through the use of bots and trolls.