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CME Credit Offered
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Recording available 2/16-5/2
Recording available 2/16-5/2
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AIUM Credit
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Abstract Award
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Foundation Awardee

Oral Concurrent Session 4 - Equity, Public Health, and Public Policy

Oral Concurrent Sessions

Oral Concurrent Session 4 - Equity, Public Health, and Public Policy

(53) Promotion of RSV Immunization Through Multiple Efforts (PRIME): a Sequential Multiple Assignment Randomized Trial

Thursday, February 12, 2026
3:00 PM - 3:15 PM  
Location: Summit 201 - 204
Abstract Award
Objective:
Persistent gaps in clinical care often require adaptive approaches that tailor intervention intensity based on individual response. Such strategies optimize efficiency by minimizing unnecessary intervention while escalating support for those who need more. To evaluate this approach for RSV vaccine uptake in pregnancy, we conducted the first individual-level sequential multiple assignment randomized trial (SMART) in obstetrics.

Study Design:
This was a Type 2 hybrid effectiveness-implementation trial at a tertiary care center. Pregnant patients eligible for RSV vaccination at 28–30 weeks gestation were randomized to routine counseling (RC) or RC plus a visual aid (RC+VA). Patients unvaccinated by 34 weeks were re-randomized to receive either a personalized electronic chart message from their physician or an educational video (EV) recommending vaccination (Figure). Co-primary outcomes were RSV vaccine uptake (effectiveness) and implementation feasibility of recruitment, fidelity, and intervention delivery.

Results:
Of 79 eligible patients, 50 (63%) were randomized (RC: n=25; RC+VA; n=25); baseline demographics were similar. All received their assigned first-tier intervention. Eighteen (36%) were vaccinated by 34 weeks; no difference was seen in uptake between groups (RC: 44%, RC+VA: 28%; p=0.239). Of the 32 who remained unvaccinated, 4 were lost to follow-up and 28 were re-randomized (personalized chart message: n=14; video: n=14), with fidelity of 100% for chart message and 79% for video. At 36 weeks, vaccine uptake was 36% for chart message and 43% for video. When analyzed by full adaptive sequence, 3 of 4 sequential strategies significantly outperformed first tier allocation alone, with vaccination rates of 72–79% vs. 28-44% (RRs 1.74-2.81) by 36 weeks (Table).

Conclusion:
This SMART demonstrated both effectiveness and feasibility of adaptive strategies to improve maternal RSV vaccination uptake. Adaptive sequences almost doubled vaccine uptake compared to first tier alone. PRIME SMART supports the use of sequential, personalized interventions to address implementation gaps in obstetric care.