Improving COVID-19 Vaccine Uptake: A Message Co-design Process for a National mHealth Intervention in Colombia

"Moving beyond top-down paternalistic perspectives that delimit the focus of health interventions and the content of health messages to embrace more context-relevant, participatory, people-centred, and reflexive multidisciplinary approaches could help develop solutions that are more responsive to the health needs of populations and public health priorities."

Latin American countries have some of the highest COVID-19 death rates worldwide, with vaccination hampered by a variety of reasons, including mis- and disinformation, vaccine hesitancy, and vaccine supply constraints. Addressing vaccine hesitancy through effective messages has been found to help increase vaccine uptake. Communication and social marketing behaviour change interventions are more effective when they are guided by theory and when they are adapted to current local contexts. This is particularly relevant to the diverse context of Colombia. The literature shows that mobile health (mHealth) interventions co-designed with the participation of different stakeholders, instead of solely scientists, may be more effective, especially when involving the audiences of focus. This article describes the methodology used to co-design evidence-based audio messages to be deployed in a cohort of individuals through an interactive voice response (IVR) mobile phone survey intervention, which aimed at increasing COVID-19 vaccination uptake among Colombian adults.

This work is part of the project entitled Digital Applications to Monitor Novel Coronavirus Disease and Response in Colombia - syndromic and vaccination surveillance (DIAMOND-R). The DIAMOND-R project, implemented between 2021 and 2023, used IVR calls to understand determinants of COVID-19 vaccine hesitancy, including knowledge, perceptions, and vaccination experiences. Data collected informed the processes of co-design and evaluation of messages to incentivise vaccination uptake as described in this article. The messages developed will be nationally deployed via an mHealth intervention through IVR.

Participants in the COVID-19 vaccination message co-design process included a sample of the general population of the country, representatives of the funder organisation, and research team members. The co-design process consisted of four phases:

1. Formative quantitative and qualitative research: The process was informed by a review of relevant literature, as well as results from mobile phone surveys and mobile phone interviews. The interview guide that shaped the data gathering was, in part, guided by the capability, opportunity, and motivation-behaviour (COM-B) model for immunisation programmes that was developed based on the Behaviour Change Wheel. The COM-B model includes questions related to determinants of vaccination behaviour and groups them into three categories: capability (individual), opportunity (contextual), and motivation (individual). The interview guide was also guided by the social determinants of health and the social marketing concept of value creation. In sum, the formative research results indicated that there was potential to incentivise people to get the next dose of the vaccine, emphasising the booster, but that challenges existed to motivate those unwilling participants to get vaccinated. To address these concerns, interview participants underlined the importance of receiving more information but also of knowing about the experience of other people with the vaccine.
2. Message drafting based on the results of the formative research: Three local research team members participated in this second phase, including by selecting excerpts from the interview transcripts and making small language edits (in Spanish) to use some of the participants' experiences in the design of the messages.
3. Message content evaluation: The content of the messages preselected in the second phase was evaluated through an online questionnaire developed for this study and a co-design workshop. The behavioural economists from the funding agency and the research team participated in this phase. The questionnaire included quantitative and qualitative questions. This phase also included a two-hour co-design workshop carried out in Spanish that engaged participants in the process of evaluating and refining messages. Examples of comments received included shortening the messages, using phrases such as "3 out of 4 people..." instead of percentages, including a call to action at the end of the messages, and minimising the use of technical jargon.
4. Evaluation of the voices to deliver the audio messages: As part of this process, after listening to each message, participants were asked if they liked the voice of the messenger, what feelings prompted the message, and if the messenger was trustworthy. They were also requested to describe the voice, and if the voice would inspire them to get vaccinated.

The four phases of the message co-design process were also informed by insights from the multidisciplinary research team that emerged during weekly reflexive meetings. In these meetings, for instance, the team discussed preliminary findings considering social, cultural, and economic aspects and the effects of the evolving vaccination context on people's intention to vaccinate. These discussions also revolved around how the gendered experiences and identities of the researchers influenced the data collection and interpretation processes, as well as the design of the messages. The need to elevate the voices and experiences of people from more peripheral regions or who represented minority groups (e.g., Venezuelan migrants and indigenous populations) was another topic of discussion by the team.

The results of the message co-design process showed that using messages that appeal to rationality and emotions and that combine individualistic and collectivistic values is important. To that end, three categories of evidence-based audio messages were co-designed, each corresponding to an arm of the mHealth intervention: (i) factual messages (called for rationality by presenting information based on data provided by relevant and trusted sources), (ii) narrative messages (appealed to emotions, drawing on the COVID-19 vaccination experiences of participants of the mobile phone interviews, guaranteeing their anonymity), and (iii) mixed messages (combined messages based on data (factual) with messages based on experiences - narrative). An additional fourth arm with no message was proposed for control.

The iterative co-design process ended with a total of 14 audio messages that were recorded various times to ensure that the tone reinforced the content and that positive feelings were transmitted in both the factual and narrative messages. For example, when recording the narrative messages, special attention was paid to emulating as closely as possible the real-life experience that inspired the message (e.g., love for the family). The average length of the factual messages was 68 seconds and of the narrative messages of 48.4 seconds. These messages will be used in an mHealth intervention to be implemented at the national level in Colombia. The results of the implemented intervention will be described in a different research article.

According to the researchers: "The iterative co-design process involving diverse stakeholders helped to develop messages with a higher potential to be effective in fostering COVID-19 vaccination. Changes in people's COVID-19 vaccine hesitancy determinants and the public health landscape were identified through the continued engagement of the co-design process participants and the constant review of evidence generated by trusted sources....Refining the quality of the messages would not have happened if the messages had been designed at a specific time and without the use of participatory approaches....Respect for participants' voices and decision-making processes related to COVID-19 vaccines and vaccination was fundamental throughout the co-design process..."

They note that "the use of mobile phones in co-design processes could help to engage hard-to-reach populations at lower costs than using in-person methods. Nevertheless, using digital technologies also has disadvantages, such as the limited possibility of establishing a deeper connection with participants as technology tools might be seen as a barrier to having more genuine and meaningful communication."

In conclusion: "Co-developing health messages in response to health emergencies is possible. Adopting more context-relevant, participatory, people-centred, and reflexive multidisciplinary approaches could help develop solutions that are more responsive to the needs of populations and public health priorities. Investing resources in message co-design is deemed to have a greater potential for influencing behaviours and improving health outcomes."

Full list of authors, with institutional affiliations: Nathaly Aya Pastrana, IMEK Centro de Investigación en Mercadeo & Desarrollo, and Pontificia Universidad Javeriana; Sandra Agudelo-Londoño, Pontificia Universidad Javeriana; Oscar Franco-Suarez, Pontificia Universidad Javeriana; Jessica Otero Machuca, Pontificia Universidad Javeriana, and University of North Carolina at Chapel Hill; Deivis Nicolás Guzman-Tordecilla d, María Camila López Sánchez, Pontificia Universidad Javeriana; Mariana Rodriguez-Patarroyo, Pontificia Universidad Javeriana; Cristhian Alejandro Rivera-Sánchez, Pontificia Universidad Javeriana; Daniella Castro-Barbudo, Pontificia Universidad Javeriana; Antonio J. Trujillo, Johns Hopkins Bloomberg School of Public Health; Vidhi Maniar, Johns Hopkins Bloomberg School of Public Health; Andres I. Vecino-Ortiz, Johns Hopkins Bloomberg School of Public Health