Characteristics of YouTube videos about the meningococcal B vaccine (4CMenB).

YouTube has become a large source of health information, and it has the capacity to influence users: for instance, regarding their vaccination habits. The aim of our study was to analyze the characteristics of the videos published on YouTube about the meningococcal B vaccine (4CMenB, Bexsero®). A search was made on YouTube using the keyword "Bexsero." The association between the authorship of videos (health professionals or others) and the rest of the variables (tone of the message and vaccination recommendations, among others) was evaluated using the Chi-square test. In total, 77 videos were analyzed; 74% supported the use of the vaccine, and the most frequently mentioned vaccination recommendations were in epidemic outbreaks (28.6%) and in children (18.2%). Depending on the type of authorship, significant differences were observed regarding the tone of the message and the frequency with which the videos discussed effectiveness, dosage, adverse effects, and vaccination recommendations. There is a difficulty in obtaining information on vaccination recommendations. Recommendations are very diverse since there is a great heterogeneity in the official recommendations for the use of this vaccine, depending on the country the information is from.