A Values-Tailored Web-Based Intervention for New Mothers to Increase Infant Vaccine Uptake: Development and Qualitative Study

"Although there has been minimal research on how to use values to effectively promote vaccination, many researchers in the field recognize its potential importance..."

Interventions to increase vaccination uptake tend to focus on correcting knowledge deficits, with the hypothesis that correcting these deficits will lead to improved attitudes and behaviours (i.e., parents become less vaccine hesitant and thus are more likely to get their children vaccinated). However, given the multiple determinants of vaccination decisions, strategies that account for factors beyond knowledge deficits, such as personal values, may prove more effective. This paper reports on the development of a values-tailored, Web-based intervention that is being used in an ongoing randomised controlled trial (RCT) aimed at improving the timeliness of infant vaccination by reducing parental vaccine hesitancy.

The setting for this project was Kaiser Permanente Colorado (KPCO), a managed care organisation in Denver, Colorado, United States (US). Between January 2015 and October 2015, various convenience samples of mothers of young children currently enrolled at KPCO were recruited for participation in the process of designing the vaccine promotion messaging intervention. The multiphase, iterative, user-centred design process of establishing the  website's architecture, content, and tailoring included:

• Creating a conceptual model reflecting empirically supported theories and intervention strategies for attitude and behaviour change - The theoretical framework was a hybrid of the Theory of Planned Behavior (TPB) and the Values-Attitudes-Behavior (VAB) model. According to the TPB, behaviour (in this case, childhood vaccination) is directly influenced by intentions (intention to vaccinate), which are based on one's attitudes, perceived norms, and perceived behavioural control. The VAB model goes beyond the TPB to posit that personal values are factors influencing attitudes (this is the basis for the hypothesis that values-tailored messaging would be an effective behaviour change target in the intervention). The researchers also used select principles of motivational interviewing (MI) and persuasive messaging to inform intervention design, with the goal of increasing the personal relevance of the materials while minimising reactance.
• Developing informational content for the intervention using data from a previous intervention, published literature, and end-user input - When possible, content was contextualised to the local Colorado environment and health system and was written at an eighth-grade reading level. All information presented was evidence based and included updated references from peer-reviewed journal articles and materials from the Centers for Disease Control and Prevention (CDC).
• Assessing the architecture of the intervention by evaluating an untailored prototype with usability testing and one-on-one interviews with potential end users of the website - The researchers solicited feedback from parents of children aged 1 to 2 years on preliminary colour schemes, logos, and general architecture of the intervention using printed prototypes.
• Iteratively developing and testing different message tailoring approaches using (i) a values survey that assessed the relationships between maternal values and vaccination beliefs (e.g., parental values pertaining to childhood vaccination decisions were measured using a scale the study team developed and assessed during this survey, called the Parental Vaccine Value Scale, or PVVS); (ii) structured interviews with potential end users of the intervention on different types of message framing approaches in combination with tailored information (e.g., 1-sided vs. 2-sided (pros and cons) messages and "push" messages vs. "pull" messages), and (iii) health communication expert and research team consensus.

Through this process, 41 specific content areas were identified to be included in the intervention. User feedback elucidated preferences for specific design elements to be incorporated throughout the website, whose home page consisted of different "tiles" representing different vaccination issues as a central navigation point. The most highly tailored information for the intervention was presented in 3 Just for You tiles representing the mothers' 3 most pressing concerns or questions regarding vaccination. The intent of these tiles was to (i) facilitate the ease with which each parent could locate the content of highest interest, (ii) increase mothers' receptivity to information about their vaccine concern(s), (iii) summarise key information about the concern, and (iv) provide mothers with access to additional information about their concern. This tile-based architecture website was perceived to be easy to use.

Seven mothers participated in interviews, which revealed that 2-sided messages were generally preferred over other message formats. For instance, they described content in the form of a table presenting information on vaccine side effects as "honest". Among the values-framed messages, most (n=4) mothers preferred statements from self-direction values-tailored versions that acknowledged their right to choose. Mothers also responded favourably to tailored messaging that specifically addressed mothers' motivation for keeping their child safe. Values-framed messages around conformity were the least preferred. Quantitative surveys identified associations between specific vaccine values and vaccination beliefs, suggesting that values tailoring should vary, depending on the specific belief being endorsed.

In the final intervention, mothers are first directed to an onboarding page designed to engage the participant in the website so they are inclined to continue to view the content. It includes a welcome message, references the participant's intention to vaccinate, explains the intent of the website and that the information presented will be tailored based on their survey responses, and visually depicts where they can find the tailored content. Following this, mothers are taken to the main home page of the intervention. On this page, the bulk of message tailoring is received via the 3 featured Just for You tiles. Any additional topics of concern beyond the top 3 concerns are highlighted within the 6 interactive tiles on this page. Tailoring on personal characteristics, including the mother's pregnancy status and child's nickname, is incorporated throughout the website content.

Reflecting on the process, the researchers note that - in line with the VAB model and elements of persuasive messaging and MI - certain values are more important than others with regard to vaccine decision making, and some values are better incorporated with certain beliefs than others. As noted above, the vaccine-hesitant parents in this study strongly preferred messages that were perceived as balanced, where both positive and negative information (i.e., 2-sided messages) about vaccine safety or benefits was presented, as these messages were deemed more trustworthy. This point supports the concept in persuasive messaging that messages deemed as trustworthy are more likely to be reflected upon and more persuasive. Also supporting the importance of persuasive messaging was the finding that messages tailored to the user were deemed more personally relevant. The MI tenet of using intrinsic motivation to effect behaviour change is also supported by the finding that mothers generally preferred values-tailored messages to those not tailored to values.

The next step in the study is to assess the efficacy of this intervention in a RCT that will examine the relative effect of the tailored versus untailored websites for their effect on timely infant vaccine utilisation during the first 15 months of life.