"This is what a war does"- Trust, information ecosystems and childhood vaccination among Ukrainian parents: A qualitative study.

Armed conflict not only disrupts health systems but reconfigures trust in vaccination and interactions with information. This study explored how the war in Ukraine has reshaped vaccine attitudes among parents living in Lviv, Ukraine and those displaced to Warsaw, Poland. Using a qualitative design, we conducted semi-structured interviews with 30 Ukrainian parents and 21 key informants, including healthcare workers, journalists, humanitarian actors and policy makers. Data were collected between November 2024 and March 2025 and analysed thematically to identify key patterns in how conflict and displacement influence trust and decision-making around childhood vaccination. Findings show that war and displacement disrupted continuity of care, with vaccination often deprioritised as families navigate documentation, housing and safety. Structural and language barriers further limited access, especially for displaced families. Yet, some parents described vaccination as a means to protect their children and reclaim their agency amid uncertainty, demonstrating active engagement with healthcare despite instability. Information practices were also reconfigured: digital platforms, particularly Telegram, became key spaces for seeking, sharing and interpreting information. Trust was shaped by perceived authenticity, responsiveness and emotional connection to information sources. This study highlights that access and vaccine confidence are mutually reinforcing. At the same time, efforts to sustain trust in vaccination must therefore go beyond focusing on information (and mis/disinformation) and draw on empathetic, transparent and participatory communication means. Strengthening continuity of care, empowering health workers and embedding community feedback mechanisms within humanitarian health responses are critical for sustaining confidence in vaccines in conflict settings.