Inequalities in severe COVID-19 by socioeconomic deprivation and country of birth, Italy, 2021–2024

Global evidence on COVID-19 related inequalities remains temporally fragmented. In this study we investigated how the associations of socioeconomic deprivation (SED) and country of birth with severe COVID-19 evolved in COVID-19 vaccinated persons residing in small/medium sized municipalities in Italy in 2021–2024. We retrospectively analysed data of 22,131,245 adults, living in municipalities with <50,000 residents, extracted from the national COVID-19 surveillance and vaccination databases. Using multivariable Cox regression we estimated annual hazard ratios (HRs) of COVID-19 hospitalisation and/or death by municipal SED quintile (Q) (relative to the least deprived Q1), and by country of birth (foreign-born vs. Italian-born). Our analyses, spanning periods with mobility restrictions (2021), and COVID-19 vaccination programs (2021–2024), were adjusted for demographic characteristics, high-risk conditions and COVID-19 vaccination, excluding the latter upon exploring the impact of the vaccine rollout on the observed associations. Deprived areas experienced increased hazard of severe COVID-19 in 2021–2022, peaking in 2021 (Q5, HR: 1.74, 95% CI: 1.59–1.91). Socioeconomic deprivation inequalities attenuated in 2023 and reversed in the most deprived areas in 2024 (Q5, HR: 0.75, 95% CI: 0.63–0.88). Foreign-born persons were disproportionately affected in 2021 (HR: 1.54, 95% CI:1.44–1.65) and to a lesser extent in 2022, diminishing to non-significant inequalities in 2023–2024. Not accounting for COVID-19 vaccination in the analysis modestly altered the COVID-19 related inequalities in 2021 to the disadvantage of deprived areas (Q5, HR: 1.84, 95% CI: 1.67–2.02) and foreign-born individuals (HR: 1.75, 95% CI: 1.63–1.87). Greater attention should be given to socioeconomically deprived areas and foreign-born people in future pandemic preparedness plans in Italy targeting small and medium sized municipalities, with particular focus on periods with mobility restrictions and initial phases of mass vaccine rollouts.