The great masquerader: primary vitreoretinal lymphoma presenting as white dot syndrome.

Migrant populations are often underserved for healthcare and preventive interventions, posing them at an increased risk of vaccine-preventable diseases, among other adverse health events (). Increasing evidence suggests that migrant populations in Europe may experience barriers to vaccination (; ; ). An evidence-informed framework () has been used to define and categorize the determinants of such barriers, including access, awareness, affordability (both direct and indirect costs, rigid scheduling), acceptance and activation. Access barriers play a major role, and include language and literacy limitations, communication challenges, digital exclusion, fear of charges, fear of immigration status checks, and service-related issues such as missing guidelines and limited knowledge among health-care providers around catch-up vaccination among this population (). Acceptance barriers are also relevant, including concerns about vaccine safety and side-effects, cultural, religious and social factors, low perceived risk of disease, lack of proactive physician recommendation, and feelings of distrust, alienation, and disempowerment (; ). Vaccine coverage has been found to be lower among migrant populations for measles-mumps-rubella- varicella (MMRV) in Germany (; ), diphtheria-tetanus-polio (DT-IPV) in Germany, France, Switzerland and the UK (; ), type b (Hib) in Germany and France (), human papillomavirus (HPV) in Denmark and Norway (; ; ; ) and influenza in Spain and France (; ), among others. Specific sociodemographic factors, such as geographical origin, recent migration (; ), low vaccination coverage in countries of origin (), socioeconomic differences (), and language difficulties () were the most significant factors associated with under-vaccination. The COVID-19 pandemic exposed severe health inequities among migrant populations, highlighting the urgent need to adopt a socioeconomic and intercultural framework in the pandemic response (). Several studies have shown that migrants were disproportionately affected by the COVID-19 pandemic (; ; ; ; ). Migrant populations are often overrepresented among essential workers, in low-income or customer-facing occupations, employed under precarious contracts or as self-employed workers, and tend to live in overcrowded and multigenerational households, further exacerbating their vulnerability (; ). Some migrant groups were found to experience higher COVID-19 mortality (; ), despite the widely accepted healthy migrant effect (; ).