Text Message Reminders to Improve Immunization Appointment Attendance in Alberta, Canada: The Childhood Immunization Reminder Project Pilot Study

"Findings support the use of SMS text message reminders as a convenient and acceptable method to minimize parental forgetfulness and potentially reduce appointment no-shows."

The literature indicates that parental forgetfulness of immunisation appointments is a key barrier to vaccine uptake among 18-month-old children. People with low socioeconomic status are more likely to have low vaccine coverage because of challenges in caring for multiple children, multiple household moves, inadequate income, and language barriers. Short messaging service (SMS) text message reminders have been shown to potentially improve childhood immunisation uptake, particularly when educational information is included; however, language barriers continue to remain unaddressed in many existing reminder and recall systems. This study aimed to assess the effectiveness and acceptability of using SMS text messages containing a link to web-based immunisation information in different languages to remind parents of their child's 18-month immunisation appointment in Canada.

The Childhood Immunization Reminder Project (ChIRP) was a pilot intervention at 2 public health centres, one each in Lethbridge and Edmonton, Alberta, Canada. Two SMS text message reminders were sent to parents: a booking reminder 3 months before their child turned 18 months old and an appointment reminder 3 days before their scheduled appointment. Booking reminders included a link to the study website hosting immunisation information in 9 languages. To evaluate intervention effectiveness, the researchers compared absolute no-show rates before (December 2017 to December 2018) and after (August 2019 to August 2020) the intervention. Google Analytics was used to determine how often web-based immunisation information was accessed, from where, and in which languages. The acceptability of the intervention was evaluated through web-based surveys completed by parents and public health centre staff.

Throughout the intervention period (May 2019 to May 2020), 3,307 booking reminders were successfully sent, including 2,885 SMS text messages and 422 voice notifications. A small number of reminders (n=133) were not delivered.

Following the intervention, the health centre in Edmonton had a reduction of 6.4% (95% confidence interval (CI) 3%-9.8%) in appointment no-shows. There was no change at the Lethbridge Health Center (0.8%, 95% CI -1.4% to 3%); however, they had higher attendance before the intervention, likely because of preexisting strategies at that site (e.g., manual reminders), so perhaps the intervention had less impact. Almost all (>95%) respondents indicated that the reminders were helpful; most of the surveyed PHC staff stated that SMS text message reminders were helpful, indicating provider support for the intervention. This reflects the readiness to engage parents in positive discussions about childhood immunisations and to encourage them to subscribe to reminder services.

All surveyed parents (222/222, 100%) found it helpful to read web-based immunisation information in their language of choice. Google Analytics data showed that immunisation information was most often read in English (118/207, 57%), Punjabi (52/207, 25.1%), Arabic (13/207, 6.3%), Spanish (12/207, 5.8%), Italian (4/207, 1.9%), Chinese (4/207, 1.9%), French (2/207, 0.9%), Tagalog (1/207, 0.5%), and Vietnamese (1/207, 0.5%).

Approximately half (51/114, 44.7%) of the parents who received the 15-month reminder reported reading the web-based immunisation information. Most participants read this information in English (47/51, 92%), found it helpful to read in their language of choice (51/51, 100%), and felt more prepared for their child's appointment (50/51, 98%).

To maximise the effectiveness of an SMS text message reminder system, the researchers suggest making it appealing to both parents and staff. For example, parents preferred later booking reminders than staff; therefore, perhaps sending both early and later reminders might be a useful compromise.

In conclusion, the study's findings support the use of SMS text message reminders as a convenient and acceptable method to minimise parental forgetfulness and potentially reduce appointment no-shows. The diverse languages accessed in web-based immunisation information suggest the need to provide appropriate translated immunisation information. However, further research is needed to evaluate the impact of SMS text message reminders on childhood immunisation coverage in different settings.