Special Populations

Increasing human mobility, of which migration is a component, is a key driver of microorganism circulation. Migration is a minor component of all human mobility, with most movement due to international tourism, travel for work, business, or study, and military operations abroad. Migration flows from southern low-income countries to the industrialized north have steadily increased as a consequences of a complex array of distal and proximal factors such as economic inequality, climate change, political turbulence, war and persecution, and family reunification. This has raised concerns about the potential transmission and reintroduction of microorganisms and infectious diseases into high-income host countries from migrants with asymptomatic infections such as tuberculosis, HIV, viral hepatitis, malaria, Chagas disease, and arboviral infections. These factors contribute to the mounting hostile attitude sometimes observed in receiving countries and deserve careful scientific assessment to inform policies and interventions. The available evidence does not support the hypothesis that migrants constitute a relevant infectious public health risk for the local population, although careful epidemiological surveillance is mandatory, especially where competent vectors for specific infection are present in the destination area, where certain diseases may potentially be introduced or reintroduced. The greatest risk of infectious diseases is to the migrants themselves due to increased risk of exposure within their own communities and from the burden of undetected and untreated infections caused by marginalization and poor living conditions. The health conditions vary at the different stages of settlement and interventions need to be tailored accordingly. In the early arrival phase the main health concerns are psychological, traumatic, and chronic conditions. Crowded unhygienic living conditions often experienced by migrants in reception camps coupled with low vaccination rate may facilitate the transmission of respiratory or gastrointestinal infections or vaccine-preventable diseases. After resettlement, undetected infections and the lack of access to health care due to social marginalization may lead to the reactivation or progression of infections such as tuberculosis, viral hepatitis, HIV, and chronic helminthiasis. These outcomes could be prevented through screening and treatment and would benefit both migrants and the host populations. Pretravel interventions that increase the awareness of the possible infectious risks in their countries of origin are critical to decrease travel-related infection among visiting friends and relatives, especially those traveling with children. Migrant-friendly health systems that ensure prompt access to diagnosis and treatment, regardless of legal status, are the best interventions to limit the burden and transmission of infections in this population.

There are 1 billion migrants in the world today, which means that one in seven of the world’s population are migrants. Of these, 272 million are international migrants and 763 million are internal migrants. It is estimated that around 70 million of the world’s migrants, both internal and international, have been forcibly displaced. Many things force people to leave their homes in search of a better future: war, poverty, persecution, climate change, desertification, urbanization, globalization, inequality, and lack of job prospects. Migrants remain among the most vulnerable members of society even when their living conditions improve after migration. Migrant women and children are a particularly vulnerable group and have a great need for basic and preventive health care. Many refugees and migrants are young and in good health, but hard living conditions and difficulty accessing basic health care can affect their state of health. Many of them face inhuman journeys during migration and live in refugee camps with very low standards of hygiene; when they find a job, they are often exploited. All these things can also affect their mental health. Migrants struggle with similar challenges as other marginalized groups when it comes to access to health care, but they face the additional barriers of mobility, language barriers, cultural differences, lack of familiarity with local health care services, and limited eligibility for publicly and privately funded health care. Governments should provide affordable preventive and basic health care to refugees and migrants not only because it is a human right but also because in the long term it can lower the costs of the whole health care system.