A Centralized Text Message Recall for Pediatric Influenza Vaccination, New York City, 2017.

CONTEXT: Influenza vaccination coverage is suboptimal nationwide.

OBJECTIVES

To evaluate the effectiveness of centralized text message recall for influenza vaccination among children conducted by the New York City Department of Health and Mental Hygiene.

DESIGN

A randomized assignment of 149 860 children, split between the intervention and control groups.

SETTING

Pediatric patients drawn from the Citywide Immunization Registry in New York City.

PARTICIPANTS

Children aged 15 months to 18 years who did not receive an influenza vaccine in the 2016-2017 season and as of the study date in the 2017-2018 season.

INTERVENTION: The Citywide Immunization Registry sent a generic Short Message Service (SMS) text message to the parents or guardians of the children: "The Health Department recommends that your child/children receive an annual flu shot. Call your doctor today!"

MAIN OUTCOME MEASURE: Risk ratios of the proportions of children who received an influenza vaccine in the intervention and control groups within 28 days after the text message was sent.

RESULTS

On October 25-26, 2017, 74 553 parents or guardians were sent a text message and 74 526 served as the control group. Of text messages sent, 73% were delivered successfully. Within 28 days of the intervention, 4.7% of children aged 15 months to 4 years in the text message group received an influenza vaccine compared with 4.3% in the control group, a statistically significant 9.5% relative increase in vaccination uptake (RR: 1.095, 95% CI: 1.001-1.199).

CONCLUSIONS

Centralized text messages had a small positive effect on influenza vaccination among younger children. This approach may contribute to improving influenza vaccination in the pediatric population.