The intervention was designed using the theory-based approach to designing interventions, using MPS middle-range theory. This approach focused on managing HPV vaccine acceptance in mothers of girls aged 9 to 12 years. The intervention was structured in five steps: understanding the problem, identifying aspects susceptible to change, establishing intervention strategies, selecting modes and doses of administration, and developing a procedures manual. In addition, the results of a qualitative study were integrated to identify mothers' needs for information about the vaccine. The intervention focused on increasing knowledge and acceptance of the vaccine, decreasing perceived barriers. It was validated through the Content Validity Coefficient (CVC), obtaining values that indicated high validity. It was delivered through a private Facebook group, where educational materials were provided and participants completed questionnaires to assess their level of knowledge. The intervention consiste

The CG did not have an educational intervention, nor the use of any placebo, the test instruments were applied and a month after this, they were invited to a virtual platform where they were asked to answer again the measurement instruments, once obtained the filling of the questionnaires they were invited and provided the user guide that allowed them to participate and learn about the Facebook group, as well as view the educational materials, to obtain the same benefits as the GE

The educational intervention was implemented through a private Facebook group, facilitating access to HPV vaccine information. A user guide was provided and profiles were verified for authenticity using a non-duplicity algorithm. Prior to access, mothers completed questionnaires to assess their knowledge, beliefs and acceptance. The intervention lasted four weeks and included four modules with videos, handouts and infographics. The first session provided information on HPV, its transmission and prevention. The second highlighted the benefits of the vaccine and debunked myths. The third showed testimonials from mothers who had their daughters vaccinated. The last session was a videoconference with group dynamics to resolve doubts. The sessions were held weekly and access and duration were monitored within the group. After finishing, the group was temporarily closed to avoid biases in the second measurement, allowing free access to the contents.

To measure knowledge of the HPV vaccine, the valid and reliable questionnaire designed by Xolocotzi, Marín, Gómez & Valenzuela (2011), applied in the Mexican context, was used. For the purposes of this study only dimension four called prevention, diagnosis and treatment was used, consisting of 8 items (28, 29, 30, 31, 33, 33, 33, 34 and 35), with a dichotomous response pattern of true and false. The result translates into, the greater the number of correct answers, the greater the knowledge of the HPV vaccine, the reliability of the instrument was through the Kuder-Richardson 20 coefficient, obtaining an rtt = .833.

A valid and reliable instrument, adapted to the Mexican context, was used to measure the factors that influence the acceptance or refusal of the HPV vaccine in mothers of girls. It consists of 40 questions grouped into six dimensions: general information about HPV (items 9-15, Cronbach's alpha .60); beliefs about HPV and the vaccine (items 16-31, alpha .58); information mechanisms (items 1-8, alpha .80); perceived benefits (items 20-22, alpha .74); barriers (items 23-26, 39-40, alpha .74); and acceptance of the vaccine (items 32-38, alpha .90). Responses are presented on a dichotomous scale (Yes/No) or in a four-point Likert format (1=strongly disagree, 4=strongly agree). The results are standardized on a 100-point scale, where higher values reflect greater knowledge, perceived benefits or acceptance of the vaccine. Overall, the instrument has a Cronbach's Alpha of .70, indicating acceptable internal reliability.

A valid and reliable instrument, adapted to the Mexican context, was used to measure the factors that influence the acceptance or refusal of the HPV vaccine in mothers of girls. It consists of 40 questions grouped into six dimensions: general information about HPV (items 9-15, Cronbach's alpha .60); beliefs about HPV and the vaccine (items 16-31, alpha .58); information mechanisms (items 1-8, alpha .80); perceived benefits (items 20-22, alpha .74); barriers (items 23-26, 39-40, alpha .74); and acceptance of the vaccine (items 32-38, alpha .90). Responses are presented on a dichotomous scale (Yes/No) or in a four-point Likert format (1=strongly disagree, 4=strongly agree). The results are standardized on a 100-point scale, where higher values reflect greater knowledge, perceived benefits or acceptance of the vaccine. Overall, the instrument has a Cronbach's Alpha of .70, indicating acceptable internal reliability.

Mothers should increase their intention to vaccinate their daughters against the human papillomavirus (HPV) with the bivalent or quadrivalent vaccine by approaching their nearest health centers. The impact of this intervention will be measured through vaccination application rates, calculated based on attendance lists from the educational institutions involved. The vaccination rate will be determined by dividing the number of vaccinated students by the total number of eligible students listed in these institutions.