Table 1.

Association between selected variables and frequency of at least one positive test among 1573 healthcare workers tested for SARS-CoV-2 in Milan, Italy, during 24 February 2020 to 31 March 2020

Characteristic	Workers	Positive test		p	ORa	95% CIa
	N	N	%
All	1573	139	8.8	—	—	7.5–10.3
Sex
Women	1010	82	8.1	0.18	1.00	Reference
Men	563	57	10.1	—	1.63	1.08–2.47
Age
<30 years	248	31	12.4	0.30	1.00	Reference
30–39 years	387	33	8.5	—	0.62	0.34–1.11
40–49 years	326	26	8.0	—	0.55	0.29–1.01
50–59 years	444	35	7.9	—	0.58	0.32–1.05
60+ years	168	14	8.3	—	0.63	0.30–1.33
Occupation
Physicians, including residents	582	61	10.5	0.15	4.15	1.55–11.1
Nurses, midwives	522	44	8.4	—	2.54	0.94–6.84
Healthcare assistantsb	162	13	8.0	—	2.27	0.75–6.86
Health technicians	170	16	9.4	—	2.61	8.88–7.69
Clerical workers, technicians	137	5	3.6	—	1.00	Reference
Any symptom
No	1070	17	1.6	<0.001	1.00	Reference
Yes	503	122	24.2	—	24.3	14.3–41.5
No. of symptoms
1	197	33	16.7	<0.001	12.5	6.79–22.9
2	149	34	22.8		18.3	9.92–33.8
3	108	36	33.3		31.0	16.6–57.8
4–7	49	19	38.8		39.2	18.6–82.9

The p values were calculated by chi-square test. Data for number of symptoms come from chi-square test for trend.

CI, confidence interval; OR, odds ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

^aFrom a multivariable logistic model including gender, age class, occupation and any symptom. Number of symptoms calculated by univariate logistic model (reference: no symptoms).

^bIncludes biologists, radiology and laboratory technicians, psychologists, other health technicians.