Immunisation status of UK-bound refugees between January, 2018, and October, 2019: a retrospective, population-based cross-sectional study.

BACKGROUND: WHO's new Immunization Agenda 2030 places a focus on ensuring migrants and other marginalised groups are offered catch-up vaccinations across the life-course. Yet, it is not known to what extent specific groups, such as refugees, are immunised according to host country schedules, and the implications for policy and practice. We aimed to assess the immunisation coverage of UK-bound refugees undergoing International Organization for Migration (IOM) health assessments through UK resettlement schemes, and calculate risk factors for under-immunisation. METHODS: We undertook a retrospective cross-sectional study of all refugees (children <10 years, adolescents aged 10-19 years, and adults >19 years) in the UK resettlement programme who had at least one migration health assessment conducted by IOM between Jan 1, 2018 and Oct 31, 2019, across 18 countries. Individuals' recorded vaccine coverage was calculated and compared with the UK immunisation schedule and the UK Refugee Technical Instructions. We carried out multivariate logistic regression analyses to assess factors associated with varying immunisation coverage. FINDINGS: Our study included 12 526 refugees of 36 nationalities (median age 17 years [IQR 7-33]; 6147 [49·1%] female; 7955 [63·5%] Syrian nationals). 26 118 vaccine doses were administered by the IOM (most commonly measles, mumps, and rubella [8741 doses]). During the study, 6870 refugees departed for the UK, of whom 5556 (80·9%) had at least one recorded dose of measles-containing vaccine and 5798 (84·4%) had at least one dose of polio vaccine, as per the UK Refugee Technical Instructions, and 1315 (19·1%) had at least one recorded dose of diphtheria-containing vaccine or tetanus-containing vaccine. 764 (11·1%) of refugees were fully aligned with the UK schedule for polio, compared with 2338 (34·0%) for measles and 380 (5·5%) for diphtheria and tetanus. Adults were significantly less likely than children to be in line with the UK immunisation schedule for polio (odds ratio 0·0013, 95% CI 0·0001-0·0052) and measles (0·29, 0·25-0·32). INTERPRETATION: On arrival to the UK, refugees' recorded vaccination coverage is suboptimal and varies by age, nationality, country of health assessment, and by disease, with particularly low coverage reported for diphtheria and tetanus, and among adult refugees. These findings have important implications for the delivery of refugee pre-entry health assessments and catch-up vaccination policy and delivery targeting child, adolescent, and adults migrants in the UK, and other refugee-receiving countries. This research highlights the need for improved data sharing and clearer definition of where responsibilities lie between host countries and health assessment providers. FUNDING: UK National Institute for Health Research (NIHR300072) and Medical Research Council (MR/N013638/1).