Table 1.
Seroprevalence (and 95% confidence intervals) of SARS-CoV-2 IgG among workers by demographic and occupational characteristics.
| Variable | Number of participants (N = 22708) | Positive (N = 1129) | Seroprevalence |
|---|---|---|---|
| N (%) | N | Prevalence [95% CI] | |
| Gender | |||
| Female | 9’095 (40.1) | 463 | 5.09 [4.64–5.54] |
| Male | 13613 (59.9) | 666 | 4.89 [4.53–5.25] |
| Age, years | |||
| <20 | 166 (0.7) | 5 | 3.01 [0.41–5.61] |
| 20–29 | 2590 (11.4) | 144 | 5.56 [4.68–6.44] |
| 30–39 | 4697 (20.7) | 213 | 4.53 [3.94–5.13] |
| 40–49 | 7355 (32.4) | 345 | 4.69 [4.21–5.17] |
| 50–59 | 6225 (27.4) | 318 | 5.11 [4.57–5.68] |
| 60–69 | 1353 (6.0) | 73 | 5.40 [4.19–6.60] |
| 70–79 | 263 (1.2) | 24 | 9.13 [5.65–12.61] |
| 80+ | 59 (0.3) | 7 | 11.86 [3.61–20.12] |
| Province | |||
| Other | 426 (1.9) | 7 | 1.64 [0.44–2.85] |
| Aosta | 475 (2.1) | 13 | 2.74 [1.27-0.75] |
| Varese | 36 (0.2) | 1 | 2.78 [0.07–14.53] |
| Asti | 888 (3.9) | 31 | 3.49 [2.28–4.70] |
| Cuneo | 2769 (12.2) | 108 | 3.90 [3.18–4.62] |
| Biella | 3205 (14.1) | 127 | 3.96 [3.29–4.64] |
| Milano | 1211 (5.3) | 60 | 4.95 [3.73–6.18] |
| Torino | 9310 (41.0) | 466 | 5.01 [4.56–5.45] |
| Verbania | 256 (5.4) | 15 | 5.86 [2.98–8.74] |
| Genova | 46 (0.2) | 3 | 6.52 [1.37–17.90] |
| Novara | 1805 (8.0) | 121 | 6.70 [5.55–7.86] |
| Alessandria | 995 (4.4) | 67 | 6.73 [5.18–8.29] |
| Vercelli | 1234 (5.4) | 99 | 8.02 [6.51–9.54] |
| Brescia | 20 (0.1) | 3 | 15.00 [0.00–30.65] |
| Bergamo | 32 (0.1) | 8 | 25.00 [11.46–43.40] |
| Occupational sector | |||
| Printing house | 115 (0.5) | 3 | 2.61 [0.00–5.52] |
| Agriculture | 359 (1.6) | 10 | 2.79 [1.08–4.49] |
| Food services | 205 (0.9) | 6 | 2.93 [0.62–5.23] |
| Information technology | 489 (2.2) | 17 | 3.48 [1.85–5.10] |
| Other manufacturing | 2061 (9.1) | 75 | 3.64 [2.83–4.45] |
| Mechanical engineering | 2577 (11.4) | 102 | 3.81 [3.08–4.53] |
| Iron and steel industry | 284 (1.3) | 12 | 4.23 [1.89–6.56] |
| Publishing industry | 46 (0.2) | 2 | 4.35 [0.00–10.24] |
| Transportation | 275 (1.2) | 12 | 4.36 [1.95–6.78] |
| Holding and insurance company | 4123 (18.2) | 192 | 4.66 [4.01–5.30] |
| Public administration | 235 (1.0) | 11 | 4.68 [1.98–7.38] |
| Construction industry | 976 (4.3) | 46 | 4.71 [3.38–6.04] |
| Plant engineering | 546 (2.4) | 26 | 4.76 [2.98–6.55] |
| Trade | 1183 (5.2) | 57 | 4.82 [3.60–6.04] |
| Other services | 2893 (12.8) | 145 | 5.01 [4.22–5.81] |
| Food industry | 1994 (8.8) | 101 | 5.07 [4.10–6.03] |
| Health services | 1115 (4.9) | 58 | 5.20 [3.90–6.51] |
| Mechanic workshop | 553 (2.4) | 29 | 5.24 [3.39–7.10] |
| Cleaning company | 75 (0.3) | 4 | 5.33 [0.25–10.42] |
| Education | 147 (0.7) | 9 | 6.12 [2.25–10.00] |
| Municipality | 16 (0.1) | 1 | 6.25 [0.00–18.11] |
| Chemical industry | 1025 (4.5) | 71 | 6.93 [5.37–8.48] |
| Food industry—meat | 14 (0.1) | 1 | 7.14 [0.00–20.63] |
| Sports | 111 (0.5) | 9 | 8.11 [3.03–13.19] |
| Clergy | 43 (0.2) | 4 | 9.30 [0.62–17.98] |
| Nursing home | 757 (3.3) | 74 | 9.78 [7.66–11.89] |
| Weaving factory | 373 (1.7) | 47 | 12.60 [9.23–15.97] |
| Logistics | 16 (0.1) | 5 | 31.25 [8.54–53.96] |