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

Abstract

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.

Trial registration: ClinicalTrials.gov NCT02761551 NCT02924467.

Keywords: centralized reminder/recall; influenza vaccine; pediatrics; population-based reminder/recall.

Figure 1:

Consort Diagram in CO and NYS with Eligibility Criteria

Figure 2:. Time-to-event analysis of flu vaccinations

Cumulative incidence curves A and C above show the cumulative percent of study subjects vaccinated over time in CO and NY, with final vaccination rates among children not already vaccinated at the start of the study ranging, from 20–25%. Smoothed hazard plots B and D show the probability of unvaccinated subject receiving a vaccination at any given time through the study period. The peak vaccination time for both states occurred shortly after the start of the intervention in October, November, and early December, with instantaneous vaccination rates decreasing through the remainder of the season. Small differences were observed between study arms at this peak vaccination time. Overall p-values for study arm from a Cox proportional hazards model, accounting for clustering within cinic, were 0.001 in CO and 0.65 in NY.