Context
According to the Ministry of Health and Social Protection, cervical cancer is the leading cause of death from cancer among women aged 30 to 59 years in Colombia [1]. The prevalence of HPV infection in Latin America is twice as high as the worldwide average and is associated with more than 68,000 new cases of cervical cancer every year [2]. Fortunately, the risk of HPV infection and the development of cervical cancer can be greatly reduced through an HPV vaccine administered free of charge in Colombia to girls and adolescents between the ages of 9 and 17. Since late 2023, boys can also be vaccinated against HPV for free to prevent oropharyngeal, anal, and penile cancers. However, HPV vaccination coverage in Bogotá is lower than expected, and only 6% of 9-year-old girls were fully vaccinated against HPV in 2016.
Project
To increase the uptake of the HPV vaccination in Bogotá, Colombia, the Inter Development Bank (IDB) Behavioral Economics Group led a study focused on developing and testing the impact of messages designed using behavioural economics principles. These messages were sent to parents of girls aged 9 to 17 years through a text message communications campaign. The initiative was a collaborative effort involving the Secretariat of Health of Bogotá, the Ministry of Health of Colombia, the American Cancer Society (ACS), the Liga Colombiana Contra el Cáncer (La Liga), and Universidad del Rosario.
The scope of this study was three-fold. First, a diagnosis was conducted to identify biases and the contextual elements that hindered parents from deciding to take action towards vaccinating their daughters. Secondly, during the human-centred design phase, low-cost/high-impact solutions were identified to overcome these vaccination barriers. Lastly, the solutions, in the form of 47 different behaviorally informed text messages, were tested against controls. The study resulted in a set of recommended messages that successfully increased vaccination rates at a low cost for the first and second doses of the HPV vaccine, respectively. Read four detailed summaries of the research here. To learn about the methodology used to design messages aimed at increasing HPV vaccination rates in Bogota, access a behavioural economics toolkit here.
In addition, ACS and La Liga created a guide and resources to promote the use and replication of messages that successfully motivated parents to choose HPV vaccination. Access these resources here (coming soon).
Behavioural Assessment
The behavioural assessment included identifying key barriers for parents in choosing to vaccinate their daughters.
Barriers to HPV vaccination uptake
The research identified the following key parental beliefs as significantly contributing to the reduced uptake of the HPV vaccine:
Government Support: A perceived decrease in government support for the HPV vaccine since the events in Carmen de Bolivar contributes to mistrust in the community and adds complexity to parental decision-making to vaccinate their children. Health professionals believe that a more explicit endorsement from the government would increase trust and make parents more likely to accept the vaccine recommendation.
Expectation of a provider recommendation: Parents expect a recommendation from their doctor for the HPV vaccine; many wait to receive a recommendation from their doctor to vaccinate. It is critical to increase recommendations to parents through multiple channels of communication, including from their healthcare providers.
HPV vaccine viewed as ‘non-essential’: Although the HPV vaccine is part of the complete vaccination schedule and appears on the vaccination card, parents do not put the same effort into vaccinating their daughters against HPV compared to other vaccines, as they deem other vaccines “more essential.” Parents frequently incorrectly believe the HPV vaccine does not appear on the national vaccination card and is not a part of the free National Immunization Program.
Lack of urgency to vaccinate: It is difficult for parents and paediatricians to appreciate the benefits of vaccination and the resulting immunity in the short term because HPV infections usually do not cause illness until adulthood. There is no immediate perceived consequence for failing to receive the HPV vaccine. HPV vaccination thus becomes something that parents feel they can put off for the future.
Lack of information and visibility: Information about the benefits of HPV vaccination is not readily available to parents in Colombia. In addition, prompts and reminders to notify parents of the need to vaccinate their child are not consistent or frequent. As a result, parents place a lower emphasis on vaccinating their children with the HPV vaccine.
Behavioural Design
Co-designing solutions to address parental barriers
Following the identification of parental barriers, we designed messages to address these barriers using behavioural tactics. The messages were delivered through a text message communications campaign to directly reach parents.
The following behavioural tactics were used to address parental barriers:
Information:
Frequently, our target population did not have the information needed to make a decision and providing more information was sufficient to nudge people into a decision and take action. For instance, although the full HPV vaccination schedule of two doses was administered at no cost to families, some parents we interviewed were unsure about the cost of the vaccine for them. In this project, we informed parents that vaccinating their daughters was free. Note that Colombia used a two-dose HPV vaccine schedule at the time of research but is now using a one-dose schedule.
Selected tactics to address barriers related to information included the following:
- Vaccine cost
- Location of vaccination points
- HPV vaccination effectiveness in preventing cervical cancer
- HPV vaccine safety
- How many parents vaccinated their daughters against HPV in recent times
- Acceptance of HPV vaccination as the expected behaviour of parents
Trust:
The source of information was important for our target audience. Based on the diagnosis interviews conducted with parents in part one of the study, we knew that information expressing government and doctor support would be assessed more favourably by parents. Thus, we explicitly included this support in the solutions to create trust with parents.
Below are the selected tactics related to vaccine trust:
- Personalised messages using the name of the recipient
- Trusted sender of text messages – In this case, messages were signed by the Secretariat of Health
- A clear recommendation for the HPV vaccination by the Secretariat of Health
- A clear physician recommendation for HPV vaccination
- Favourably comparing the safety of the HPV vaccine with other more routinely administered vaccines
Framing:
The way information was presented had a big impact on people’s understanding of it and on the actions they subsequently took. For example, highlighting the negative aspect of a decision can cause an option to be perceived as more—or less—attractive. To emphasise the importance of the vaccine, we informed parents about HPV infection and cervical cancer prevalence using various framing tactics to highlight the necessity of the vaccine. Additionally, we varied the way we presented information on infection, prevalence, and vaccine effectiveness, by testing messages using percentages, raw numbers, or qualitative terms.
Below are the selected framing tactics:
- Parents’ responsibility to protect their daughters by vaccinating them against HPV
- Potential consequence of developing cervical cancer due to HPV infection
- Grouping the HPV vaccine with the set of government-recommended vaccines that have yet to be completed
Decision aids:
Decision aids are intended to empower individuals or groups by providing them with support and assistance in making decisions, particularly when faced with complexity or uncertainty. These have been effective in a wide range of fields, including healthcare uptake.
Below are the selected decision aid tactics included in the messages:
- Call to action
- Reminders of upcoming HPV vaccine appointments
- Eliciting the intention to vaccinate against HPV
- An interactive map showing the closest vaccination centre
- A phone number to call in case of questions related to HPV vaccination
- Pre-scheduled appointments to administer the vaccine
Solutions
To reach parents, we developed a text message campaign based on the above behavioural tactics. Text messaging was the selected channel due to the Secretariat of Health of Bogota’s existing practice of communicating via text to reach the community. To assess the effect of the behaviorally informed text messages on parents’ decisions to vaccinate their daughters, we used administrative records from the Secretariat of Health that showed whether or not a girl/adolescent got vaccinated after the campaign.
Evaluating Solutions
The evaluation strategy used a randomised controlled trial that consisted of six large field tests in Bogotá, Colombia. These tests evaluated 47 alternative ways to communicate with parents through text messages using behavioural science principles to address barriers and increase HPV vaccination in Bogotá. The target population included two groups: parents of unvaccinated girls and parents of girls who started but did not complete the HPV vaccination schedule. Each test evaluated between 3 and 11 behaviourally informed text messages and contained three control groups. Control group one, the pure control group, did not receive any messages. Control group two, the policy control group, received a message similar to those the Secretariat of Health of Bogotá had sent in the past. Control group three, the experimental control group, received placebo messages. Each test group was divided into two sub-groups, with only one receiving follow-up messages.
Results
In the tests targeting unvaccinated girls (“first-dose tests”), the most impactful messages addressed mistrust and salience barriers. Reinforcing the doctor’s recommendation, government support for the vaccine, and emphasising the HPV vaccine as the safest in the immunisation schedule significantly increased first-time vaccination rates.
In the tests focused on girls with incomplete schedules (“second-dose tests”), a simple reminder to parents about their daughter’s necessary vaccine proved to be the most effective treatment. This reminder showed a notable increase, statistically significant at the 99 percent confidence level, compared to the pure control group’s average vaccination rate. Messages combining a simple reminder with other behavioural tactics were also effective but to a lesser extent.
Translating Insights into Action
Based on the research, we recommend the following as part of future HPV vaccine uptake initiatives in Colombia:
Use one or more of these effective behavioural tactics when implementing a text message campaign:
- Frame the HPV vaccine as a cancer-preventing vaccine.
- Increase trust in the vaccine by stating that it is supported by physicians and institutions like the Ministry of Health and Social Protection.
- Reinforce the safety of the vaccine; compare it favourably with other routine immunisations, if appropriate.
- Remind parents of their responsibility to get their daughters vaccinated against HPV and protect them from cervical cancer.
- Provide decision aids and clear direction for parents to schedule a specific place and time where they can vaccinate their daughters.
- Messages can be used and/or reinforced by incorporating them into other communication channels used by an institution. Examples include in-clinic posters, parent handouts, emails, mailings, social media, and website/patient portal content.
- Communicate recent increases in HPV vaccination rates in their community, city, and country.
References:
1. Ministry of Health Colombia. Cáncer de cuello uterino [Internet]. [cited 2024 Jan 31]. Available from: https://www.minsalud.gov.co/salud/publica/ssr/Paginas/Cancer-de-cuello-uterino.aspx
2. Nogueira-Rodrigues A. HPV Vaccination in Latin America: Global Challenges and Feasible Solutions. Am Soc Clin Oncol Educ Book. 2019 May;(39):e45–52. Available from: https://ascopubs.org/doi/10.1200/EDBK_249695