What's in a name? – How migrant populations are classified and why this matters for (in)equitable access to routine childhood and adolescent immunisation services: A scoping review

BACKGROUND: Migrant populations may be highly susceptible to vaccine-preventable diseases (VPDs) due to factors such as mobility, legal status, and systemic health inequities. We explore systemic barriers to equitable immunisation services for migrant children and adolescents worldwide. METHODS: We conducted a scoping review following Arksey and O'Malley's framework, with guidance from Joanna Briggs Institute guidelines. Our search across 10 databases yielded 78 peer-reviewed articles (2012-2023) and nine grey literature sources from global organizations. Data were charted and analysed to identify trends in vaccine coverage, classification of migrant populations, and policy implications. RESULTS: Despite the existence of national immunisation programmes with migrant-inclusive policies in some countries, significant barriers remain. Lower immunisation rates and higher VPD risks are common among migrants, with exclusion often based on legal status. Misalignment between home and host country policies further restricts access. CONCLUSION: Policy reforms are needed to harmonize immunisation policies across borders and ensure equitable access irrespective of migrant classification. Increased collaboration between health systems in home and host countries is critical to achieving these goals.