Flu Shot Reservation Text Messaging May Improve Vaccination Rates

Alison Buttenheim, PhD, MBA

Influenza vaccination uptake may be improved by health systems sending strategically-phrased text message reminders to patients, according to findings from a Philadelphia-based trial.

The findings—which come in the same week as other research from Philadelphia showing Black patients’ buy-in to text-message telemedicine for blood pressuring monitoring, as well as findings from Finland showing improved flu vaccination rates in regions receiving reminder mail—are just the latest supporting individualized public health message strategies for regular vaccination.

Led by Alison Buttenheim, PhD, MBA, of the Department of Family and Community Health at the University of Pennsylvania School of Nursing, investigators sought to interpret the effect of text messages informing patients that a seasonal flu vaccine had been “reserved” for them at their health system on the actual flu vaccination rate for that season.

Their research, which occurred with primary care patients from the Penn Medicine and Geisinger Health systems based in Pennsylvania, would look to complement emerging measures of addressing vaccine hesitancy—one of the World Health Organization’s (WHO) top 10 global threats of 2019. As they noted, the COVID-19 pandemic has only delivered more challenges to ensuring annual flu vaccination—while also showing the importance of the practice.

“In 2019 to 2020, only 48% of the US adult population received an influenza vaccine, and national polls indicate that large numbers of Americans remain hesitant to receive one of the COVID-19 vaccines, even as the vaccine is rolled out,” investigators wrote. “Behavioral interventions can increase vaccine uptake.”

The team observed previous research showing that automatic, cancellable scheduling for vaccination appointments can improve vaccination rates over routine vaccine reminders. “Furthermore, social processes such as the norm of reciprocity and mental frames such as scarcity guide behavior,” they explained.

This newest study uses specific language for the patients’ text message notifications, crafted from an assessment of 19 different messages: the phrase “a flu shot has been reserved for you” was deliberately chosen for its framing of vaccination as a default or expected action, as well as the emphasis on patient reciprocation and ownership of their own vaccine dose.

Buttenheim and colleagues hypothesized this message would help improve flu vaccination rates compared with similar messages that did not use such language.

The randomized clinical trial observed 11,188 adult primary care patients from Penn Medicine or Geisinger Health to receive either a text message stating “a flu shot has been reserved from you,” a text message stating “flu shots will be available,” or no message. Investigators sought a primary outcome of influenza vaccination received on the date of the patient’s scheduled appointment, and additionally observed whether patients indicated interest in vaccination by their response to the text messages, which prompted them to reply either yes (Y) or no (N).

Patients in the 2 message groups were sent 3 consecutive SMS messages containing the selected phrasing on the evening prior to their scheduled appointment.

Of the selected patients originally treated between September 20, 2020 and March 31, 2021, 10,158 were included in the study. Mean patient age was 50.6 years old; 55.43% were women and 69.2% identified as White. Based on health records, 40.5% of patients had been vaccinated in the prior flu season; 53.4% of patients were treated at Penn Medicine.

The investigators’ intent-to-treat analysis showed changes in vaccination rates in response to the “reserved vaccine” message were not statistically significant—only an increase by 1.4 percentage points, or 4% (P = .31) versus the “available vaccines” message. Compared to non-message intervention, the “reserved vaccine” message improved vaccination rate by 3.3 percentage points, or 11% (P = .004).

Additionally, patients in the “reserved vaccine” message group were more likely to respond Y to the message (n = 1064 [31.5%]) versus those in the “available vaccines” message group (n = 887 [26.5%]; P <.001). Patients who replied Y to the message were more likely to get the flu shot (n = 1532 [78.6%]) than those who did not (n = 749 [15.7%]; P <.001).

The team emphasized the findings show the “effect size” of specific reservation language for improving vaccination rates.

“Our results contribute to the rapidly accumulating evidence on ownership messages to promote vaccination, which have now been tested for COVID-19 vaccination as well as other outcomes,” they wrote.

Though the trial is limited by the reach of the 2 participating health systems and availability of flu shots from other clinics and pharmacies, as well as the inability to assess impact on patients not already seeking health care, the investigators concluded that sending strategically-phrased text message reminders about flu shots may have even incremental benefit for vaccination rates.

“While this study did not detect a statistically significant difference between the two text message conditions, given the low cost of altering the wording in a text message, it may be useful to consider using a “reserved for you” message when promoting vaccination behavior,” they wrote.

The study, “Effects of Ownership Text Message Wording and Reminders on Receipt of an Influenza Vaccination,” was published online in JAMA Network Open.