SARS-CoV-2 infections and hospitalizations among immigrants in Norway – significance of occupation, household crowding, education, household income and medical risk. A nationwide register study

Abstract

Background: As in other countries, the coronavirus disease 2019 (COVID-19) pandemic has affected Norway's immigrant population disproportionately with significantly higher infection rates and hospitalizations. The reasons for this are uncertain. Methods: Through the national emergency preparedness register, BeredtC19, we have studied laboratory-confirmed infections with SARS-CoV-2 and related hospitalizations in the entire Norwegian population, by birth-country background for the period 15 June 2020 - 31 March 2021, excluding the first-wave due to limited test capacity and restrictive test criteria. Straightforward linkage of individual-level data allowed adjustment for demographics, socioeconomic factors (occupation, household crowding, education, and household income), and underlying medical risk for severe COVID-19 in regression models. Results: The sample comprised 5.49 million persons, of which 0.91 million born outside of Norway, 82 532 confirmed cases, and 3088 hospitalizations. Confirmed infections in this period (per 100 000): foreign-born 3140, Norwegian-born with foreign-born parents 4799, Norwegian-born with Norwegian-born parent(s) 1011. Hospitalizations (per 100 000): foreign-born 147, Norwegian-born with foreign-born parents 47, Norwegian-born with Norwegian-born parent(s) 37. The addition of socioeconomic and medical factors to the base-model (age, sex, municipality of residence) attenuated excess infection rates by 12.0% and hospitalizations by 3.8% among foreign-born, and 10.9% and 46.2% respectively among Norwegian-born with foreign parents, compared to Norwegian-born with Norwegian-born parent(s). Conclusion: There were large differences in infection rates and hospitalizations by country background, and these do not appear to be fully explained by socioeconomic and medical factors. Our results may have implications for health policy, including the targeting of mitigation strategies.

Transmission of SARS-CoV-2 into and within immigrant households. Nation-wide registry-study from Norway

“…Though there are many studies showing higher infection rates among ethnic minority and immigrant groups originating from West-Asia and Africa also after adjusting for demographic, socioeconomic, household and medical factors [1][2][3][4][5][6], we are not aware of any previous study of transmissions into and within immigrant households. Previous studies of household SAR do not focus on differences in transmission across country of origin, and results on intra-household transmissions of SARS-CoV-2 are inconclusive, as the studies are few and small, with different designs, and report widely varying SARs [8,[11][12][13][14][15][16][17][18].…”

“…Not only household size, but for example also housing space may contribute to the spread of the virus [4]. Norwegian advice has been that when isolating at home, cases should have as little contact with other family members as possible including where possible, their own bathroom and meals brought to them.…”

“…Differences in social contact patterns, traveling and occupational risks have also been suggested as possible partial explanations [3][4]19]. The recently published consensus statement from SAGE in the UK concludes that households are important drivers of COVID-19 transmission [3].…”

“…Ethnic minority groups originating from West-Asia and Africa have been hit harder by COVID-19 than Ethnic Europeans in many European and North American countries [1][2][3]. Norway is no exception, as immigrants from Pakistan and Somalia, amongst others, have suffered more infections and hospitalizations than non-immigrants [4][5]. While some of the overrepresentation can be attributed to socioeconomic deprivation, substantial overrepresentation prevails after adjustment for demographic, socioeconomic, household and medical factors [1][2][3][4][5][6].…”

“…Norway is no exception, as immigrants from Pakistan and Somalia, amongst others, have suffered more infections and hospitalizations than non-immigrants [4][5]. While some of the overrepresentation can be attributed to socioeconomic deprivation, substantial overrepresentation prevails after adjustment for demographic, socioeconomic, household and medical factors [1][2][3][4][5][6]. More knowledge is needed to design and implement measures that can break the chains of transmission.…”