PurposeTo evaluate the influence of viewing the Olfatín Project video on the assessment of school LAIV-associated pain in three and four-year-old children through the Wong Baker Faces® pain classification scale. Design and methodsA three-arm randomized multicenter clinical trial with a placebo control group was carried out. The main variable measured was pain, assessed through the score on the Wong Baker Faces® Pain Rating Scale. There were a total population of 4591 children three and four-year-olds (born in 2019 and 2020) and who attended the 1st and 2nd year of early childhood education. Before the school vaccination, researchers randomly assigned participant schools corresponding to each of the basic health areas to each of the three study groups: Olfatín's video viewing, a control video viewing not related to influenza and no video viewing. ResultsNo significant differences according to sex, age or the minor's grade according to the assigned intervention were detected. 72.3% of those vaccinated assigned a 0 from the Wong Baker Faces® scale: 75.4% of those who watched Olfatín's video, 68.3% for those in Drilo's group and 72.8% for those who didn't watch any video, but without significant differences (p = 0.08). There were no significant differences either stratifying by sex. ConclusionLAIV is a painless vaccine for children, which has to be taken into account by the health authorities when planning the pediatric influenza vaccination campaign. Practice implicationsOlfatín's cartoon video can be used by professionals to create a greater experience for children and therefore a better acceptance.