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Transmission of SARS-CoV-2 into and within immigrant households: nationwide registry study from Norway


Background Minority groups and immigrants have been hit disproportionally hard by COVID-19 in many developed countries, including Norway.

Methods Using individual-level registry data of all Norwegian residents, we compared infections across all multiperson households. A household with at least one member born abroad was defined as an immigrant household. In households where at least one person tested positive for SARS-CoV-2 from 1 August 2020 to 1 May 2021, we calculated secondary attack rates (SARs) as the per cent of other household members testing positive within 14 days. Logistic regression was used to adjust for sex, age, household composition and geography.

Results Among all multiperson households in Norway (n=1 422 411), at least one member had been infected in 3.7% of the 343 017 immigrant households and 1.4% in the 1 079 394 households with only Norwegian-born members. SARs were higher in immigrant (32%) than Norwegian-born households (20%). SARs differed considerably by region, and were particularly high in households from West Asia, Eastern Europe, Africa and East Asia, also after adjustment for sex and age of the secondary case, household composition and geography.

Conclusion SARS-CoV-2 is more frequently introduced into multiperson immigrant households than into households with only Norwegian-born members, and transmission within the household occurs more frequently in immigrant households. The results are likely related to living conditions, family composition or differences in social interaction, emphasising the need to prevent introduction of SARS-CoV-2 into these vulnerable households.

  • COVID-19
  • epidemiology
  • statistics
  • social sciences

Data availability statement

No data are available. The individual-level data used in this study are not publicly available due to privacy laws. However, the individual-level data in the registries compiled in BeredtC19 are accessible to authorised researchers after ethical approval and application to administered by the Norwegian Directorate of eHealth. Stata do-files are available upon request.

This article is made freely available for personal use in accordance with BMJ’s website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.

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