Table 2.

Risk of infection of SARS-CoV-2 among cases and controls from the Lisbon and Tagus Valley Region in September and October 2020 according to education level, citizenship status, and known contact with a case.

	Odds ratio (95% CI)	P-value
Education level
Reference: Tertiary	(n = 1,873)
≤ 4 years	1.79 (1.33–2.42)	<0.001
6 years	3.85 (2.50–6.08)	<0.001
9 years	2.16 (1.61–2.90)	<0.001
12 years	2.23 (1.78–2.81)	<0.001
Citizenship
Reference: Portuguese	(N = 1,851)
Non-portuguese	5.47 (3.43–9.22)	<0.001
Known contact with a case
Reference: No	(N = 1,874)
Yes	24.76 (16.45–39.18)	<0.001

95% CI, 95% Confidence Interval.