TABLE 2. Prevalence of antibodies against SARS-CoV-2 according to socioeconomic and demographic characteristics.

	Number of positive samples	Seroprevalence (%)	Prevalence ratio (95% CI)
			Unadjusted	Adjusted for sex and age	Adjusted for sex, age, and region
Region		p < 0.001b		p < 0.001b
North	1 065	6.7	31.94 (21.09; 48.38)	33.26 (21.94; 50.41)
Northeast	776	2.9	13.90 (9.14; 21.14)	14.15 (9.30; 21.52)
Southeast	149	0.7	3.27 (2.10; 5.11)	3.27 (2.10; 5.10)
South	31	0.2	Reference (1)	Reference (1)
Center-West	43	0.4	2.11 (1.28; 3.48)	2.14 (1.29; 3.52)
Wealth quintiles		p < 0.001c		p < 0.001	p < 0.001b
Poorest	621	3.0	2.16 (1.86; 2.52)	2.16 (1.86; 2.51)	1.43 (1.23; 1.66)
2nd	449	2.7	1.98 (1.68; 2.33)	1.98 (1.69; 2.31)	1.48 (1.27; 1.73)
3rd	389	2.3	1.64 (1.40; 1.92)	1.64 (1.39; 1.92)	1.39 (1.19; 1.63)
4th	369	2.1	1.56 (1.33; 1.84)	1.56 (1.33; 1.83)	1.44 (1.23; 1.69)
Richest	236	1.4	Reference (1)	Reference (1)	Reference (1)
Schooling (years)a		p < 0.001c		p < 0.001c	p < 0.001c
≤ 4	326	2.3	1.55 (1.31; 1.83)	1.84 (1.54; 2.20)	1.46 (1.24; 1.75)
5 – 8	347	2.3	1.77 (1.49; 2.09)	1.90 (1.61; 2.26)	1.72 (1.46; 2.03)
9 – 11	722	2.6	1.71 (1.49; 1.98)	1.71 (1.48; 1.97)	1.46 (1.27; 1.68)
≥ 12	253	1.5	Reference (1)	Reference (1)	Reference (1)
Color / ethnicity		p < 0.001b		p < 0.001b	p < 0.001b
White	372	1.2	Reference (1)	Reference (1)	Reference (1)
Brown	1 237	3.1	2.69 (2.39; 3.02)	2.71 (2.41; 3.05)	1.49 (1.32; 1.68)
Black	282	2.5	2.17 (1.86; 2.53)	2.18 (1.87; 2.54)	1.36 (1.16; 1.59)
Asian	52	2.1	1.85 (1.38; 2.48)	1.86 (1.39; 2.49)	1.10 (0.82; 1.49)
Indigenous	66	5.4	4.71 (3.65; 6.08)	4.73 (3.67; 6.11)	2.25 (1.74; 2.90)

Source: prepared by authors from the results.

^aSubjects < 20 years were excluded

^btest for heterogeneity

^ctest for linear trend