Text messages to people who are reluctant to get their flu shots—or simply forget—have helped boost uptake in the past, but these “nudges” didn't move the needle when it came to COVID vaccines.
That’s the conclusion in a new report from Brown University’s Policy Lab, published in Nature on Wednesday. Researchers found that text message reminders sent out to unvaccinated Rhode Islanders in late spring 2021 didn’t increase COVID-19 vaccine uptake.
The problem was not the texts themselves, however, the report’s authors argue. It was bad timing: By the time unvaccinated people in the Ocean State received the nudges in May 2021, most state residents had been able to get a shot for months.
“In the beginning of 2021, the vaccines were still a novelty,” said Kevin Wilson, associate director of data science at the Policy Lab and a co-author of the study. “Everyone who wanted a vaccine was strategizing how to get one as early as possible. I remember friends frantically calling me, saying, ‘You need to log in to the appointment system at exactly 12:00 and fill out the form as quickly as possible!’ I would have been ecstatic to get a text message with a link that showed me exactly where to go and what to do.
“But three months later, it’s going to be more difficult to get good results from a text campaign. There’s an abundance of vaccines, there’s less urgency, and the number of people who could get vaccinated has shrunk.”
The authors say that “far from a repudiation of those results,” the report in fact “offers important additional information on when text-message vaccination campaigns work and when they don’t”
These takeaways could be helpful to health officials across the U.S. as they work to keep people healthy and out of hospitals by promoting COVID-19 and influenza vaccine uptake, the team concluded.
“We now have more information that can help people who are thinking seriously about how and when to make public health interventions,” said Wilson. “We’ve unlocked another piece of the puzzle.”
Nathaniel Rabb, a project manager at the Policy Lab, added that the study confirms it’s crucial for public health officials to kick off text-message campaigns at the right “inflection point,” when there’s an increased demand for vaccinations.
There’s a reason text message campaigns for the flu shot work better in October than in February, he said: It’s a key juncture at which children have recently returned to school, physicians emphasize the importance of immunization and the flu season begins.
The team had used a variety of messaging for the COVID vaccine texts, and all the messages contained what researchers call “ownership language,” or words and phrases that speak directly to the message’s recipient—exactly the sort of thing typically used for flu shot nudges.
“Ownership language could be a way of cutting through the perception that getting a vaccine is complicated,” Rabb said. “It conveys this message of, ‘We’re going to make this easy for you. There’s no red tape. We’ve got a vaccine ready, set aside, just for you.’”
But regardless of what content was used, the text messages had no meaningful effect on COVID vaccine uptake. Even the text message that had the biggest positive effect on uptake—which described how the vaccine could prevent “bad COVID-19 outcomes”—didn't deliver a statistically significant result. It drove just 2.2% of recipients to get a vaccine, compared to 2% of those who didn’t receive any message.
Want your message to work? Make sure you get the timing right.