SARS-CoV-2 incidence and hospitalisation in South Tyrol (Italy): a population-based ecological study

Literature associating SARS-CoV-2 spread to environmental variables such as altitude, tourism, vaccination adherence and demographics, is inconclusive and contrasting. This study aimed at studying these relationships during the first unrestricted winter in South Tyrol, a multicultural Italian alpine province. Methods: An ecological study was performed, based on the 20 districts of the area. Data about incidence and hospitalization between November ’21 and February ’22 was collected and associated to geographical, demographic and health-related characteristics via bivariate analyses. Results: Incidence (range: 15% - 22%) and hospitalization (range: overall = 0.09% - 0.26%/ intensive care unit (ICU) = 0 - 0.06%) varied widely among districts. Incidence showed positive correlations with average altitude (Rho = 0.62, p < 0.001), tourist amount (0.54, p < 0.04) and average family size (0.66, p < 0.005); whereas negative ones with vaccination coverage (-0.62, p < 0.04) and population density (-0.44, p < 0.05). Similar trends were observed for ICU admissions. Incidence was significantly higher in Ladin speaking districts and lower in Italian ones, while ordinary wards admission appeared lowest in Ladin districts and higher in the Italian ones, as well as close to main cities and hospitals. Conclusions: Living in urban districts, geographically and linguistically closer to the Health Authorities, may have played a protective role against infection and severe disease, through an increased adherence to public health preventive measures. The concomitant higher rate of admissions might be due to the easier access to the structures. By contrast, infection spread was higher in rural and sparsely populated districts, associated with greater winter tourism and family sizes, but also characterized by lower herd immunity and institutional closeness. More attention should be paid to communities with special needs (geographical and cultural) to ensure equitable means for future pandemics.