A Cluster Randomized Controlled Trial to Improve Influenza and Tdap Vaccination Rates for Pregnant Women.

INTRODUCTION: We evaluated the impact of a provider and nurse-based intervention on influenza and Tdap vaccination rates among pregnant women. METHODS: The VAX-MOM trial was a 2-arm cluster randomized clinical trial conducted across 4 health systems (14 obstetric practices in Rochester, NY, and 13 in Los Angeles, CA), from April 2021 to June 2022. Practices were randomized to receive provider and nurse training via online modules (covering influenza and pertussis infections, vaccination, and workflow changes, such as presumptive vaccine recommendations) or standard care. Co-primary outcomes were influenza and Tdap vaccination rates for women delivering live births during the intervention. Analyses adjusted for clustering within practices. RESULTS: The study included 5992 and 6768 women eligible for Tdap vaccination, and 4609 and 5294 women eligible for influenza vaccination (intervention and control practices, respectively). Influenza vaccination rates declined by 5% in the intervention group (57% to 52%) and by 10% in the control group (57% to 47%). Tdap vaccination rates increased by 3% in both groups (67% to 70% in intervention; 72% to 75% in control). Adjusted analyses showed influenza vaccination rates were 8% higher in intervention practices (aRR 1.08, 95% CI [1.00, 1.15], p = 0.038; not significant given the p < 0.025 cutoff for 2 outcomes). Tdap rates showed no significant difference. Post-hoc analysis excluding one minimally engaged system revealed influenza vaccination rates were 13% higher in intervention practices (aRR 1.13, 95% CI [1.06, 1.19], p < 0.001). CONCLUSION: Provider and nurse training improved influenza vaccination rates but did not significantly affect Tdap coverage in engaged practices.