Published on Investing in Health

Being Behaviorally Savvy in Vaccine Communication

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Asian woman waiting to get COVID19 vaccine. Photo: Shutterstock
Asian woman waiting to get COVID19 vaccine. Photo: Shutterstock

In the history of public health, vaccines continue to be one of the greatest solutions and to date have saved countless lives. However, hesitancy towards vaccination was a problem before the COVID-19 pandemic and continues to be a challenge with the rollout of COVID-19 vaccines across the globe. Reasons for vaccine hesitancy vary from country to country. Misinformation and lack of consistent messaging about the COVID-19 vaccines can lead to confusion and low-risk perceptions about the odds of getting ill . Hesitancy toward the COVID-19 vaccines may also be influenced by the speed of their development which raised safety concerns for some. Lastly, the goal of vaccines is to prevent severe illness and hospitalization, infection is still possible, but poor outcomes are far less likely. These are a few examples of underlying reasons for vaccine hesitancy, but beliefs are as diverse as people themselves.

With COVID-19 vaccines offering great protection in reducing the risk of hospitalizations and death, why has addressing vaccine hesitancy been such a challenge?

Those attempting to answer this question might be well-intended but could be taking a one-sided approach to the problem. One of the common mistakes is applying a generalized blanket solution to increase vaccine acceptance . Often it is assumed that a “communication campaign” can solve the problem without first understanding the root cause of an issue; this can lead to poor outcomes.

Instead of beginning with a public health campaign alone, behavioral science may be a better starting point to consider psychological, social, as well as economic factors that affect how people behave and think. Based on the context of the environment, society, political influences, and culture, the root cause of the problem will differ from one country to the next. Social norms, attitudes, needs, and wants of the target audience must be taken into account when thinking of behavioral interventions.

In a recent blog, we highlighted some insights and lessons from work we have been doing at the World Bank to support countries understand and reduce vaccine hesitancy using behavioral science. The work is done through social media surveys and randomized experiments, allowing us to understand people’s beliefs about COVID-19 and vaccination intentions. The information is then used to inform the countries’ behavior-change communications to address vaccine hesitancy.

Here, we are zooming in on leveraging three essential ingredients to address vaccine hesitancy: social norms, framing of the content, and trusted messengers.

We first must remember that vaccine hesitancy lives on a spectrum . On one end there is a completely vaccine-resistant subgroup, on the other, there are early vaccine adopters, with agreeable champions, individuals concerned about safety, those uninformed on COVID-19, and low-vaccine-trust individuals in between. Hesitancy varies across demographics, behaviors, and beliefs. The correct communication strategy must be data-informed . Measuring target populations’ social norms, intention to vaccinate, belief, and trust in vaccines is the essential prerequisite for crafting audience-specific interventions.

Social norms will be a key starting point for the right form of communication

Social norms are the informal, mostly unwritten, rules that define acceptable, appropriate, and obligatory actions in a given group or society. As we are social beings, we care about what those around us believe and do, and more importantly: their actions and beliefs influence us. Relying on personalized normative feedback, where people receive information on how they are performing against others around them, can help achieve higher vaccination rates. In the case of COVID-19, where vaccination is low, we can appeal to “dynamic” social norms by telling people that more and more people are getting vaccinated. An example is: “More and more of your neighbors are getting vaccinated, 10,000 people in your community received their COVID vaccine in the last week, don’t miss out! Get your vaccine today,” compared to a general messaging that simply implores “Get vaccinated!”. In our work in North Macedonia, we found that this appeal to dynamic social norms had a large effect by increasing the intent to be vaccinated by 39%.

It may seem surprising, but message framing, including message tailoring, is sometimes even more critical than the message content to achieve behavior change. Customized messages are more personally relevant, thus attracting more attention.  In Jordan, providing vaccine messaging that addresses an individual's specific concern was effective at encouraging intent to vaccinate. For example, those who reported concerns about the COVID vaccine efficacy were most likely to have an increased intent to get vaccinated when shown a message highlighting vaccine efficacy along with a reminder that they would be protecting friends and family. This group’s intent to vaccinate increased by 21%, compared to control messages. This demonstrates the importance of adapting the messaging, so it is responsive to the individual’s concern. 

How relevant are messengers?

Some of the biggest concerns among those who are unwilling to get the COVID-19 vaccine include long-term side effects, already having had COVID-19 illness, concerns of the vaccine being ineffective, or just simply recognizing that there is still no long-term data available. As we are influenced by those around us, relying on trusted messengers can make a difference in changing the target audiences’ planned action to vaccinate from unsure to consenting to vaccinate.  For example, using health care workers as a messenger can build trust, as seen in the message below, used in Iraq. For individuals with low trust, messages referencing doctors resulted in a 57% increase in intent to get vaccinated.

Corona virus vaccineSimilarly, in Cameroon, when shown messages with endorsement from experts and religious leaders, the intent to vaccinate was increased by 83% compared to the control message. While trusted messengers vary by country and local context, this finding highlights the importance of utilizing locally trusted sources for vaccine communication campaigns.

Finally, one flaw in traditional health behavior change interventions is the reliance on the target audience to use cognition and reflection as they are attempting to extinguish undesired behavior. But, if a task absorbs too much of our attention, we will quickly revert to the easiest way, the status quo. This adaptation allowed for our evolutionary survival given that default behaviors preserve our cognitive capacity. How can we use and manipulate our wiring to achieve the health outcomes we are after? For vaccine hesitancy that would mean making vaccination easier for the target audience, and altering the environment to present the easiest option, the default option, becomes vaccination. Some of the suggestions would be leveraging general providers to automate vaccination appointments, providing free transportation to vaccination sites, sending vaccination reminders via texts, and securing mobile vaccination units for hard-to-reach populations. Some of our current work revolves around this, and we will share results as we get them.

Increasing vaccination globally will require many different strategies. Harmonizing existing strategies with behavior science principles is a complementary element that can be leveraged to create strong vaccine communication and policies and vaccine take-up. 

The work, led by the Mind, Behavior, and Development (eMBeD) unit of the Poverty and Equity Global Practice (GP), the Health, Nutrition and Population GP, and the Development Impact Evaluation Department (DIME) is supported in part by the Alliance for Advancing Health Online (AAHO), an initiative to advance public understanding of how social media and behavioral sciences can be leveraged to improve the health of communities around the world.


Corey Morales Cameron

Behavioral Science Consultant

Renos Vakis

Lead Economist, Poverty and Equity Global Practice, World Bank

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