A Mega-Study of Text-Based Nudges Encouraging Patients to Get Vaccinated at an Upcoming Doctor’s Appointment

Abstract
Many Americans fail to get life-saving vaccines each year, and the availability of a vaccine for COVID-19 makes the challenge of encouraging vaccination more urgent than ever. We present a large field experiment (N=47,306) testing 19 nudges delivered to patients via text message and designed to boost adoption of the influenza vaccine. Our findings suggest text messages sent prior to a primary care visit can boost vaccination rates by up to 11%. Overall, interventions performed better when they were (a) framed as reminders to get flu shots that were already reserved for the patient and (b) congruent with the sort of communications patients expected to receive from their healthcare provider (i.e., not surprising, casual, or interactive). The best-performing intervention in our study reminded patients twice to get their flu shot at their upcoming doctor’s appointment and indicated it was reserved for them. This successful script could be used as a template for campaigns to encourage the adoption of life-saving vaccines, including against COVID-19.

A Mega-Study of Text-Message Nudges Encouraging Patients to Get Vaccinated at their Pharmacy

Abstract
We partnered with Walmart to test 22 nudges designed to boost vaccination rates in their pharmacies. Nudges were delivered via text message to over 700,000 Walmart pharmacy patients in the fall of 2020 and encouraged patients to visit Walmart for a flu vaccine. We demonstrate that the best behaviorally informed messages can increase pharmacy vaccination rates by up to 8.3% compared to the least effective messages over a roughly one month follow-up period. The most effective messages in our field experiment matched the tone of typical pharmacy communications and reminded patients that a flu shot was waiting for them. These insights suggest that carefully crafted messages informed by the results of this study could nudge the adoption of other vaccines for other infectious diseases, including COVID-19.