Carnegie Mellon University
August 02, 2021

Text Reminders Boost Vaccine Appointments

Researchers find text messages that impart psychological ownership are an effective method to encourage people to sign up and show up for COVID-19 vaccinations

By Stacy Kish

Stacy Kish
  • Dietrich College of Humanities and Social Sciences

Researchers at Carnegie Mellon University and the University of California, Los Angeles found text nudges are an effective way to remind people to schedule their first vaccination appointment and show up. The results of the study are available in the Aug. 2 issue of the journal Nature.

"Vaccination is super important to return to normalcy," said Silvia Saccardo, assistant professor in the Department of Social and Decision Sciences at CMU and contributing lead author on the paper. "Our goal was to make vaccination salient to people and remove barriers to action by giving them the link to where they could schedule appointments."

Vaccination efforts have been hindered by safety concerns, fear and misinformation. A research team conducted two large, randomized and controlled trials to identify methods that could overcome common barriers — like forgetfulness, cost and procrastination — to scheduling an appointment and getting the vaccine. The study was conducted from February to March 2021, during phase 1 eligibility for people over 65 years of age or with a pre-existing condition.

"One simple reminder, which is cost effective, could prompt people to schedule their appointment." — Silvia Saccardo

Saccardo was joined by Hengchen Dai at UCLA. They applied their expertise in behavioral science to construct the study. They partnered with Daniel Croymans in internal medicine at UCLA Health to coordinate on patient outreach.

After initial notification of eligibility for the vaccine, participants in the first randomized trial received one of four types of text message or no text reminder. Each of the five groups consisted of more than 22,000 people. The text nudge was subdivided into four styles: 1) a simple text reminder; 2) simple text reminder with an informational video; 3) a text crafted with ownership language like, "The vaccine has just been made available for you," and 4) a text with ownership language and the informational video.

The text message boosted appointment rates at UCLA Health. The baseline appointment rates within six days were at 7.2% among patients without a reminder, while patients who received a reminder increased their appointments to 13.2%, an 84.33% increase. In addition, the text message accelerated how quickly the vaccinations were scheduled and acquired, increasing vaccination rates at UCLA Health within a month from 13.89% to 17.56%. This approach was particularly effective with the population that typically schedules a seasonal flu shot, and the benefits even held when the researchers examined vaccinations obtained outside of UCLA Health clinics.

The video message did not improve appointment schedules or vaccinations. The researchers point to low video view rates to explain this result.

"I was most surprised that adding an information intervention to text reminder did not yield a detectable effect on actual vaccination behaviors among UCLA Health patients," said Dai, assistant professor at the UCLA Anderson School of Management and contributing lead author on the paper. "It is very interesting that while a video-based intervention seems to elevate vaccination intentions in a hypothetical setting where people are asked to watch the video, this intervention does not yield benefits in the field where people are invited to watch the video and where we assess actual behavior."

The second randomized trial consisted of more than 67,000 people who were divided into two groups. One group received a reminder text and the other did not. On the eighth day following the initial invitation, the reminder group received the second text message. Patients in this group were randomized to one of six scenarios: 1) a simple text reminder; 2) a text emphasizing the social benefit of vaccination; 3) early access to vaccine appointment text; 4) early access and social benefit text; 5) fresh start text, and 6) fresh start and social benefit text.

They found when people get a second reminder, they were more likely to schedule their first dose within six days (1.65 percentage points) and obtain the vaccination (1.06 percentage points). While the change is small, Saccardo and Dai point to the hesitant population getting vaccinated.

According to Saccardo, vaccination strategies should focus on helping people overcome barriers to scheduling the first dose. Text reminders proved to be an effective method to motivate people across demographic groups. Reminders that induced feelings of psychological ownership outperformed reminders using a different approach.

"One simple reminder, which is cost effective, could prompt people to schedule their appointment," said Saccardo. "Getting scheduled for the first dose was the biggest barrier. Once scheduled, people went to the appointment and then returned for their second dose."

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