Area-level social and economic factors and the local incidence of SARS-CoV-2 infections in Victoria during 2020

Objective: To examine associations between area-level socio-economic factors and the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Victoria during 2020. Design, setting: Population-level ecological study of the incidence of SARS-CoV-2 infections in Victoria, by postcode, 1 March - 13 August 2020. Main outcome measures: Relationships between the incidence of SARS-CoV-2 infections by postcode (Department of Health and Human Services data published on The Age website), and demographic, education level, ethnic background, economic and employment-related factors, housing-related factors, and social disadvantage (Australian Bureau of Statistics data for 2014-19), expressed as incidence rate ratios (IRRs). Results: During the study period, 15 482 SARS-CoV-2 infections with associated postcodes were recorded in Victoria. Incidence was higher for metropolitan than regional postcodes (418.3 v 62 infections per 100 000 population; IRR, 6.2; 95% CI, 4.6-8.2). In regional postcodes, incidence rose with mean household size (per person: IRR, 7.30; 95% CI, 4.37-12.2), unemployment proportion (per percentage point: IRR, 1.50; 95% CI, 1.33-1.69), and proportions for whom rent (IRR, 1.15; 95% CI, 1.07-1.22) or mortgage repayments (IRR, 1.22; 95% CI, 1.15-1.28) exceeded 30% of household income. In metropolitan areas, incidence increased with unemployment proportion (IRR, 1.14; 95% CI, 1.05-1.23) and proportion without paid leave (IRR, 1.22; 95% CI, 1.02-1.45). Incidence also increased with proportion speaking languages other than English at home (regional: IRR, 1.08; 95% CI, 1.06-1.11; metropolitan: IRR, 1.01; 95% CI, 1.002-1.02) and with Indigenous Australian proportion (metropolitan only: IRR, 1.91; 95% CI, 1.10-2.73). Conclusions: Socio-economic factors may have contributed to the non-homogeneous incidence of SARS-CoV-2 infections across Victoria during 2020.