Low Childhood Vaccination Coverage among Ukrainian Refugees in Norway. A Nationwide, Register-Based Cohort Study, 2022-2023.

Low vaccination coverage is highlighted as a challenge in Ukraine and among Ukrainian refugees, however there is limited knowledge on coverage among Ukrainian refugees living in European countries. Individual-level data from the National Population Register for children (<20 years) with at least one parent from Ukraine were linked to the Norwegian Immunisation Registry (SYSVAK). We estimated vaccination coverage according to Norwegian Childhood Immunisation Program recommendations among 1) Ukrainian refugee children (i.e. immigrated after 01.02.2022) (N = 8,804) and 2) children born in Norway to Ukrainian refugee parent(s) (N = 224), compared to national coverage. National coverage rates were 95.8% to 96.5% (2-year-olds), 94.5% to 96.7% (9-year-olds), and 90.0% to 94.0% (16-year-olds). Corresponding rates among Ukrainian refugee children were 39.5% to 60.5%, 27.3% to 58.6%, and 9.2% to 34.3%, respectively. Coverage among Norwegian-born children of Ukrainian refugees was >91%. In all, 31% of Ukrainian refugee children had no vaccinations registered in SYSVAK. Coverage for Human Papilloma Virus (HPV) catch-up vaccination among Ukrainian refugee boys was lowest (9%), however, routine HPV vaccination coverage was 63%. Ukrainian children with a refugee background showed lower vaccination coverage than the national coverage. We found large differences between routine versus catch-up vaccination. Our findings suggest that access to catch-up vaccination, routines for retrospective registration of vaccines given outside of Norway and surveillance reporting, as well as vaccine hesitancy should all be considered when assessing childhood vaccination coverage among Ukrainian refugees. These factors should be addressed to improve vaccine uptake and surveillance in this population.