[The impact of COVID-19 on the immigrant population in Italy. Context, methodology and synthesis of the main evidence from the project of the National Institute for Health, Migration and Poverty (INMP) and Italian Regions].

COVID-19 acted on health inequalities in two ways: directly, in terms of infection risk and outcomes; indirectly, through effects on the economy, which exacerbated social inequalities. Immigrants have particularly suffered the effects of the pandemic.The Italian National Institute for Health, Migration and Poverty (INMP) has promoted the project "Epidemiology of SARS-CoV-2 (COVID-19) infection and use of health services in immigrant and vulnerable population groups in Italy" in collaboration with the Regions of Piedmont, Lombardy, Veneto, Emilia-Romagna, Tuscany, Lazio, and Sicily, to assess the impact of the pandemic in the immigrant population.This is an observational population-based study design, based on weekly monitoring data from the COVID-19 National Surveillance System of the Italian National Health Institute (ISS). The observation period was split into five sub-periods: February-May 2020 (wave I), June-September 2020 (intermediate period I), October 2020-January 2021 (wave II), February-April 2021 (wave III), May-July 2021 (intermediate period II).Access to diagnostic testing was higher among Italians; the incidence curve showed a lower level of infection among immigrants during the three waves and higher in the two intermediate periods. Age-standardized hospitalization rates were higher among immigrants both in noncritical care areas and in the intensive care unit, particularly in the intermediate stages of the epidemic. Immigrant standardized mortality rates were higher than those of Italians since the third period among males and in the fourth period among females.Differences were also observed on a regional basis and by the immigrants' area of origin.