Impact of the CARD (Comfort Ask Relax Distract) system on school-based vaccinations: A cluster randomized trial

The CARD (Comfort Ask Relax Distract) system is a vaccine delivery framework that integrates evidence-based interventions to reduce stress-related responses and improve the vaccination experience for children undergoing vaccinations at school. In preliminary studies, CARD was acceptable and effective. The objective was to evaluate CARD in a large, pragmatic trial to confirm its effectiveness in real-world settings.

Hybrid effectiveness-implementation cluster randomized trial in schools receiving vaccination services from Wellington-Dufferin-Guelph Public Health. Forty schools with grade 7 students (12 years old) were randomized to CARD and control (n = 20/group). Nurses in CARD schools planned clinics with principals and educated students about CARD ahead of time. Principals disseminated information to staff and parents and sent reminders. Vaccination day processes minimized fear and facilitated student self-selected coping strategies. Nurses in control schools followed usual practices, which excluded principal meetings, education, reminders, and systematic integration of fear-reducing or child-selected coping strategies. Outcomes included stress-related symptoms (fear - primary outcome, pain, dizziness, fainting, post-vaccination reactions), use of coping interventions, vaccination uptake, attitudes and implementation outcomes (acceptability, appropriateness, feasibility, fidelity).

Altogether, 1919 students were included. Fear and pain were lower in CARD schools: OR 0.65 (95% CI 0.47-0.90) and OR 0.62 (95% CI 0.50-0.77), respectively. No students fainted in CARD schools compared to 0.8% in control (p = 0.02). Dizziness and post-vaccination reactions did not differ. Student-led coping interventions were used more frequently in CARD schools. Vaccination uptake was 76.1% in CARD schools and 72.5% in control schools (OR 1.13 (95% CI 0.85-1.50)). Staff and students had positive attitudes about CARD and implementation outcomes; however, recommendations were made to improve fidelity.

CARD reduced stress-related responses in students undergoing vaccinations at school and was positively received by students and public health staff. CARD is recommended to improve the quality of vaccination delivery services.

NCT03966300.