Addressing HPV Vaccine Hesitancy by Co-Designing a Digital Health Intervention

Feasibility of implementation: Acceptability, appropriateness and feasibility of implementation

Measured using Weiner et al.'s implementation outcomes questionnaire (administered to school nurses in participating schools). The questionnaire consists of 12 statements, with four items each assessing the Acceptability of Intervention Measure (AIM), the Intervention Appropriateness Measure (IAM), and the Feasibility of Intervention Measure (FIM). Respondents rate their level of agreement with each statement using a five-point Likert scale, ranging from "completely disagree" to "completely agree." Responses are coded numerically from 1 to 5, with higher scores indicating stronger agreement. The 12 scores are summed to produce a total scale score ranging from 12 to 60, with higher scores reflecting more positive perceptions of the platform across the three implementation domains.

Time frame: Shortly after the intervention period (i.e., 'end of treatment') at 7 months.

Feasibility of implementation: Acceptability, appropriateness and feasibility of implementation

Qualitative data will be collected through semi-structured interviews with school nurses in participating schools. An interview guide developed guided by the Consolidated Framework for Implementation Research (CFIR) will be used to ensure consistency while allowing flexibility to explore individual experiences in depth. The guide includes open-ended questions designed to capture perceptions (see outcome measure 5) and questions related to implementation, e.g., 'How did you experience implementing HPV-Kompassen alongside the regular school health services program?' and 'How well did HPV-Kompassen fit with how schools provide information about HPV vaccination?'.

Time frame: Shortly after the intervention period (i.e., 'end of treatment') at 7 months.

Acceptability of intervention: Intervention delivery strategy

Defined as proportion of adolescents and caregivers that access platform at least once, measured through platform usage metrics.

Time frame: Throughout the intervention period (i.e., months 0-7).

Acceptability of intervention: Usability of intervention

Usability is measured quantitatively using the Swedish version of the System Usability Scale (SUS). The SUS consists of 10 items assessing perceived usability across key dimensions such as complexity, ease of use, and confidence in using the system. Participants (school nurses, adolescents and caregivers) indicate their agreement with each item on a five-point Likert scale ranging from "strongly disagree" to "strongly agree." Responses are scored according to standard SUS procedures, resulting in a total score ranging from 0 to 100, with higher scores indicating better perceived usability.

Time frame: Immediately after the intervention period (i.e., 'end of treatment') at 7 months.

Acceptability of intervention: Perceptions of intervention

Qualitative data will be collected through semi-structured interviews with participants (school nurses, adolescents and caregivers), focusing on their perceptions of the intervention. An interview guide is used to ensure coverage of key domains while allowing flexibility to explore individual experiences in depth. The guide includes open-ended questions assessing implementation (see outcome measure 2) and perceptions of the intervention, such as "Can you briefly describe your experience of using HPV-Kompassen?" and "Did the information seem credible to you?".

Time frame: Shortly after the intervention period (i.e., 'end of treatment') at 7 months.

Acceptability of intervention: Intervention engagement

Defined as proportion of adolescents and caregivers that actively engage with the platform least once (e.g., visit different modules), measured through platform usage metrics.

Time frame: Throughout the intervention period (i.e., months 0-7).

Acceptability of intervention: Intervention engagement

Qualitative data collection using semi-structured interviews. These interviews aim to understand how, why, and to what extent participants engaged with the platform in practice. Participants (school nurses, adolescents and caregivers) are asked open-ended questions such as "Why did you choose to use the platform?" and "Why did you not use the platform, or use it less than expected?" Additional questions explore when and how the platform was accessed, which features were used, and what factors influenced engagement (e.g., time constraints, relevance of content, or integration with existing workflows).

Time frame: End of intervention period (i.e., 'end of treatment') at 7 months.

Feasibility of trial protocol: Feasibility of recruitment

Measured through study notes, assessing two indicators: proportion of schools that consent to participate and proportion of participants that consent to participate in interviews.

Time frame: From start of school enrollment (i.e., pre-intervention) and throughout the intervention period (i.e., months 0-7).

Feasibility of trial protocol: Participant retention

Measured using study records and platform metrics, assessing two indicators: Proportion of schools retained until study end and proportion of participants using platform who complete the end line survey.

Time frame: From school enrollment (i.e., 'baseline') and throughout the intervention period (i.e., months 0-7).

Feasibility of trial protocol: Feasibility of data collection methods

Measured using study records and survey data, assessing the completeness of data.

Time frame: Shortly after the intervention period (i.e., 'end of treatment') at 7 months.