Asylum seekers' and Refugees' Changing Health (ARCH) study protocol: an observational study in Lebanon and Denmark to assess health implications of long-distance migration on communicable and non-communicable diseases and mental health.

Ethical approval has been obtained in Lebanon and Denmark. In the short term, we will present the cross-sectional association between long-distance migration and the results of the throat and wound swab, blood and faeces samples and mental health screenings. In the longer term, we are planning to follow the refugees in Denmark with collection of dried blood spots, mental health screenings and semistructured qualitative interviews on the participant's health and access to healthcare in the time lived in Denmark. Here, we present an overview of the background for the ARCH study as well as a thorough description of the methodology.