Table 1.

Main characteristics and odds ratios of SARS-CoV-2-reinfected individuals in Liguria.

Variable		Reinfection (15,715)	PDs (53,891,505)	Incidence Per 10,000 PD	Unadjusted OR (95% CI)	p-Value	Adjusted OR (95% CI)	p-Value
Epidemic phase	Delta	161	958,178	1.68	Reference		Reference
	Transition	903	4,013,487	2.25	2.36 (1.99–2.79)	<0.001	2.40 (2.03–2.84)	<0.001
	Omicron	14,651	48,919,840	2.99	4.89 (4.19–5.72)	<0.001	5.27 (4.51–6.17)	<0.001
Vaccination Status	Vaccinated with at least one dose for ≤120 days	5350	22,330,172	2.40	Reference		Reference
	Vaccinated with at least one dose for >120 days	4581	14,764,645	3.10	1.18 (1.13–1.23)	<0.001	1.29 (1.25–1.35)	<0.001
	Unvaccinated	5784	16,796,688	3.44	1.26 (1.22–1.31)	<0.001	1.62 (1.55–1.69)	<0.001
Gender	Male	6812	25,089,342	2.72	Reference		Reference
	Female	8903	28,802,163	3.09	1.17 (1.13–1.21)	<0.001	1.11 (1.08–1.15)	<0.001
Age-group	0–19	3235	12,177,126	2.66	1.37 (1.29–1.46)	<0.001	1.22 (1.15–1.30)	<0.001
	20–39	4293	12,222,708	3.51	1.84 (1.74–1.96)	<0.001	1.76 (1.66–1.87)	<0.001
	40–59	5804	17,582,644	3.30	1.77 (1.68–1.88)	<0.001	1.66 (1.57–1.76)	<0.001
	60–79	1588	8,776,040	1.81	Reference		Reference
	≥80	795	3,132,987	2.54	1.46 (1.34–1.60)	<0.001	1.52 (1.39–1.66)	<0.001
Nationality	Italian	14,080	304,189	462.87	Reference		Reference
	Non-Italian	1635	30,928	528.65	1.15 (1.09–1.21)	<0.001	1.04 (0.99–1.10)	0.1016
Healthcare worker	No	14,265	51,391,133	2.78	Reference		Reference
	Yes	1450	2,500,372	5.80	2.38 (2.25–2.52)	<0.001	2.43 (2.29–2.58)	<0.001

CI, confidence interval; OR, odds ratio; PDs, person days. Adjusted ORs include all factors in the table, mutually adjusted for each other.