49 - Increasing Influenza and Tdap Vaccination Rates for Pregnant People: A Cluster-Randomized Trial (RCT)

Poster Number: 49
Publication Number: 49.1438

Background: Infants < 6 mo old are at increased risk of both influenza (flu) and pertussis disease. Pregnant individuals are at increased risk of serious illness and premature labor from flu. ACOG and others recommend that pregnant individuals receive a flu vaccine during the flu vaccination season, and Tdap vaccine during each pregnancy (ideally between 27-36 weeks) to lower the risk for flu and pertussis disease for themselves and their infants. However, only 47% and 55% of pregnant people in the U.S. receive a flu and Tdap vaccine, respectively.

Objective: Measure the effect of a multi-component, scalable intervention, on flu and Tdap vaccination rates (27 OB/GYN practices) using a cluster RCT study design.

Design/Methods: Four health systems (2 in LA, CA, 2 in Rochester, NY) participated in the RCT (July 2021-June 2022). Practices were randomized within health systems and balanced by size, to receive the intervention or standard of care control. In intervention practices, we implemented clinician/nurse training via online modules (45 min) to: assess vaccine status, use a strong recommendation with presumptive language to recommend flu/Tdap, and use provider prompts or standing orders. Vaccine champions completed monthly Plan-Do-Study-Act (PDSA) cycles to describe office changes. We employed intent-to-treat analyses using robust Poisson mixed models with practice random effects to estimate the effect of the interventions on patient vaccination rates, adjusting for clustering within practice.

Results: 12 intervention and 15 control practices participated (Table 1). Average baseline vaccination rates were 57.0% and 56.7% in intervention and control practices for flu, and 72.7% and 78.7% for Tdap at any time in pregnancy. Adjusting for baseline rates, flu vaccination rates increased in intervention compared to control practices by 8% (aRR 1.08 [1.00, 1.15], p=0.04; Table 2). There was no increase in rates of Tdap given at 27-36 weeks (aRR 0.94 [0.88, 1.00], p=.06) or Tdap vaccination rates overall (aRR 0.94 [0.91, 1.02], p=0.21. By health system, the intervention raised flu vaccination by: 12% in 2 systems, 10% for Tdap (27-36 weeks) in 1 system, and 2-3% for Tdap any time during pregnancy in 2 systems (Table 3).

Conclusion(s): A multi-component intervention, applying strategies used for other vaccines (improving communication, provider prompts and feedback), increased flu vaccination rates for pregnant people. Rates for Tdap vaccination, which were high at baseline, improved less. OB offices may have better compliance with recommendations designed to protect infants after receiving vaccination systems training.