Abstract
Previous studies have demonstrated that text message reminders can improve pediatric vaccination rates, including low income & diverse settings such as those served by federally qualified health centers. In this study, we aimed to improve compliance with routine childhood immunizations via a text message intervention in a network of urban, federally qualified health centers at a large academic medical center. We targeted parents or guardians of children aged 0-2 years who were overdue or due within 14 days for at least one routine childhood immunization without a scheduled appointment. In Round 1, two versions of a text were compared to a control (no text). In subsequent Rounds, a new text was compared to a control (no text). In each round the content, wording, and frequency of texts changed. Subjects were randomized to receive a text (treatment group(s)) or to not receive a text (control group) in each round between 2020 and 2022. The primary outcome was whether overdue vaccines had been given by 12 week follow up. The secondary outcome was appointment scheduling within the 72 hours after text messages were sent. In Round 1 (n=1203) no significant differences were found between groups in overdue vaccine administration per group or per patient at follow up, or in appointment scheduling. In Round 2 (n=251) there was no significant difference in vaccine administration per group or per patient. However, significantly more patients in the intervention group scheduled an appointment (9.1% vs. 1.7%, p=0.01). In Round 3 (n=1034), vaccine administration was significantly higher in the intervention group compared to the control overall (7.0% vs. 5.5%, 0.016) and per subject (p=0.02). Significantly more patients in the intervention group scheduled an appointment compared to the control (3.3% vs. 1.2%, p=0.02). We found that text messaging can be an effective intervention to promote health service utilization such as pediatric vaccination rates, which although improved in this study, remain low.