Defining the determinants of under-vaccination in migrant populations in Europe to improve routine and COVID-19 vaccine uptake: a systematic review (preprint)

ABSTRACT

Diverse migrant populations in Europe are at risk of under-immunisation and have recently shown lower levels of COVID-19 vaccination intent and uptake. Understanding the determinants of vaccine uptake in migrants is critical to address immediate COVID-19 vaccination inequities, and longer-term will help improve coverage for routine vaccinations, aligning with the goals of the new Immunisation Agenda 2030. We did a systematic review following PRISMA guidelines and using a PICOS framework (PROSPERO CRD42020219214; MEDLINE, CINAHL, PsycINFO databases, 1 January 2000 to 14 September 2021) exploring barriers and facilitators to vaccine uptake and determinants of under-vaccination in migrants in the EU/EEA, UK, and Switzerland. We categorised barriers/facilitators using the 5As Determinants of Vaccine Uptake Taxonomy. 5259 data sources were screened, with 67 studies included from 16 countries, representing 366,529 migrants. Access barriers were most commonly reported (language, literacy and communication barriers; practical and legal barriers to accessing/delivering vaccination services; service barriers, including lack of specific guidelines and knowledge of healthcare professionals) for key vaccines including MMR, DTP, HPV, influenza, polio, COVID-19 vaccines. Acceptance barriers were mostly reported in Eastern European and Muslim communities for HPV, measles, and influenza vaccines. We identified 23 determinants of under-vaccination in migrants, including geographical origin (where 25/26 (96%) studies showed significance) - particularly African/Eastern European origin; recent migration; being a refugee/asylum seeker; higher income; parental education level; no healthcare contact in the past year; and lower language skills. Facilitators of migrants' vaccine uptake included tailored vaccination messaging, community outreach and nudging interventions. Migrants' barriers to accessing healthcare are already well documented, and this review confirms their role in limiting vaccine uptake. These data hold immediate relevance to strengthening vaccination programmes in high-income countries, including for COVID-19. Our findings suggested that targeted, evidence-informed strategies are needed to address access and acceptance barriers to vaccination in migrants, including the development of migrant-sensitive and adaptable vaccination services and systems, unambiguous public health messaging, and coproduction of tailored interventions.