Centralized Reminder/Recall to Increase Influenza Vaccination Rates: A Two-State Pragmatic Randomized Trial

Objective: Centralized reminder/recall (C-R/R) by health departments using immunization information systems is more effective and cost effective than practice-based approaches for increasing childhood vaccines but has not been studied for influenza vaccination. We assessed effectiveness and cost of C-R/R for increasing childhood influenza vaccination compared with usual care.

Methods: Within Colorado (CO) and New York (NY), random samples of primary care practices (pediatric, family medicine, and health center) were selected proportionate to where children are served-65 practices (N = 54,353 children) in CO; 101 practices (N = 65,777) in NY. We conducted 4-arm RCTs per state (1, 2, or 3 autodial reminders vs usual care), with randomization at the patient level within practices from 10/2016 to 1/2017.

Results: In CO, the maximum absolute difference in receipt of ≥1 influenza vaccine was 1.7% between the 2 R/R group and control (adjusted risk ratio [ARR] of 1.06 [1.01, 1.10]); other R/R arms did not differ significantly. In NY, ARRs for the study arms versus control varied from 1.05 (1.01, 1.10) for 3 R/R to 1.06 (1.01, 1.11) for 1-2 R/R groups and maximum absolute increase in vaccination was 0.6%. In time-to-event analyses, study arm was a significant predictor of vaccination in CO (P = .001) but not in NY. Costs/child randomized to one message were $.17 in CO and $.23 in NY.

Conclusions: C-R/R for influenza vaccine using autodial had low-level effects on increasing influenza rates in 2 states. Given the feasibility and low cost of C-R/R in previous trials, its utility for influenza should be re-examined using different modalities.