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  • 15th Mar 2021

Four messages that can increase uptake of the COVID-19 vaccines

Using large-scale testing to identify effective vaccine messaging

More than one in four people in the US say they are unwilling to get the COVID-19 vaccine. That statistic is especially concerning because many are from the communities that have been hit hardest by the pandemic. There is an urgent public health need, therefore, not only for the vaccine itself but also for effective messaging to ensure uptake. This is the question we addressed in our latest US trial. 

Here’s what we did

Over the last few months, we have been developing, refining, and testing vaccine messages. We used an iterative process that involved scanning the existing behavioral science literature on vaccine uptake, running 5 randomized controlled trials, and hosting 15 focus groups in English and Spanish. 

In our final trial, we tested four final messages in English and Spanish with 20,000 people, using our online research platform, Predictiv. The messages were:

1. Helping Loved Ones tapped into people’s desire to protect and support their friends and family. It made clear that vaccinating yourself can help your loved ones while being careful not to overstate the vaccine’s power to reduce or eliminate transmission.

2. Approved by Healthcare Workers used the credibility and authority of healthcare workers as trusted messengers. The message emphasized how most people have demonstrated confidence in the vaccine by taking it themselves. 

3. Getting Lives Back drew on the powerful motivation to return to the activities and people they are missing, without promising that life will ever fully go back to “normal.”

4. Tested by Thousands built trust in the vaccine development process, without getting bogged down in overly technical details or medical jargon. The message incorporated aspects of ‘social proof’ by indicating that millions of people have already taken the vaccine safely.

We used two measures to evaluate these messages: our primary measure was vaccine confidence, a composite of measures on safety, efficacy, and importance of the COVID-19 vaccine. Our secondary measure was stated willingness to vaccinate. 

The results 

All four messages increased vaccine confidence and willingness to vaccinate by 3-4 percentage points, a relative increase of approximately 6%. If those increases translated to action, it would mean over 10 million more residents getting vaccinated in the US. Even more encouraging was the fact that the messages were effective for groups most affected by COVID-19. 

While all of our messages were effective at boosting confidence and willingness to get vaccinated, one message was particularly effective. The Helping Loved Ones message increased willingness to vaccinate across all hesitant groups. While we recommend rotating through multiple high-performing messages, the strength of the “Helping Loved Ones” message makes it a good candidate to lead campaigns.  

Moving forward, we are working to get these results out to policymakers and other stakeholders who can translate our recommendations into real-world outreach. However, our results go beyond specific messages – they show that good communication can be a powerful tool to increase health equity. We encourage policy makers, elected officials, and others to use these insights to increase confidence in COVID-19 vaccines. 


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Dr Michael Hallsworth

Managing Director, BIT Americas

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Sheena Mirpuri

The Behavioural Insights Team

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Read more of our COVID-19 work