Outbreak to uptake: driving MMR coverage through Social and Behavior Change in Novi Pazar, Serbia

Abstract Issue/problem Reaching zero-dose children remains a global public health challenge, with 14 million children missing out on vaccines in 2023. Novi Pazar, a multicultural city in Serbia, faced a low MMR1 vaccination coverage in 2023 (57.3%), leading to a measles outbreak in 2024, which grew to 872 cases and 1 fatality by March 2025. Description of the problem Since July 2024, the Institute of Public Health Novi Pazar has led a UNICEF-supported project to improve childhood immunization through a behaviorally informed multistakeholder approach (involving health, education, local self-government, religious communities, NGOs, media, and judiciary system). Methods included formative research (parent and physician surveys), behavioral insights to develop communication materials, health worker training on interpersonal communication (IPC), parents’ education, as well as systemic changes in primary health centers (PHCs), preschool enrollment, and legal procedures. Results The coordinated effort increased MMR1 coverage by 15% over 6 months (Sept 2024-Mar 2025), establishing a sustainable, locally owned immunization strategy. The multistakeholder approach engaged 186 actors from 20+ institutions. Behavioral drivers of hesitancy were detected: fear of autism; misinformation; low trust and perception of measles risk; inconsistent advice; and systemic barriers. IPC training was completed by 64 health workers, reaching 724 hesitant parents. Workshops for 150 parents resulted in a 98% increase in understanding. 8 organizational changes were made in PHCs, and 36 media events raised awareness. Revised procedures reduced systemic change barriers. Lessons Tackling public health crises in low-trust, low-coverage settings demands a committed multistakeholder team and insights from formative research to shape effective interventions. A multistakeholder approach tackles the social and systemic roots of hesitancy and requires improved procedures and local ownership. Key messages • Behavioral insights helped tackle deep-rooted MMR fears and mistrust, boosting coverage by 15% in Novi Pazar's complex setting. • Tackling multisystem challenges through collaborative action, targeted communication, and health system strengthening is vital for immunization program success.