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Three Questions

How Nudges Could Boost Vaccination Rates

COVID-19 vaccines are now available to all American adults, but vaccination rates are slowing. A study co-authored by Yale SOM’s James Choi tested a variety of text messages to prompt people to get flu vaccines, offering one potential tool to encourage those who aren’t rushing to get a COVID shot. We asked Choi what the study showed about the effectiveness of these nudges, and whether they can make a difference now.

A woman looking at her phone while walking
Bjorn Bakstad/iStock

What does your research suggest about the effectiveness of texted “nudges” to get people to get a flu vaccine?

Nudges work in this context! We ran a randomized experiment on 47,306 patients that tested 19 different text-message nudges. The average nudge boosted the vaccination rate by 2.1 percentage points above the baseline (no-nudge) vaccination rate of 42%, which is a relative increase of 5%. This nudge raised vaccination rates by 4.6 percentage points. Surprising, casual, or interactive messages were less effective, maybe because patients don’t expect to receive those kinds of communications from their healthcare provider.

How can we apply this work to COVID-19 vaccinations?

We could deploy a similar strategy for patients who have an upcoming primary care appointment, reminding them twice by text to ask for a COVID vaccine at their appointment and saying that a vaccine is reserved for them. This could help increase vaccination rates in some of the pockets of the population that are slower to get vaccinated.

Does polarization around COVID-19 and the vaccines present extra challenges for this kind of nudge?

A nudge is not going to cause somebody who is dead set against vaccination to get vaccinated, and somebody who is highly motivated to get vaccinated will get their shot whether or not they are nudged. Nudges work on people who are close to the vaccine-versus-no-vaccine margin. To the extent that polarization causes this nudgeable middle to shrink, nudges will be less effective.

Department: Three Questions