Association between SARS-CoV-2 and exposure risks in health care workers and university employees – a cross-sectional study

Figures & data

Table 1. Baseline characteristics and SARS-CoV-2-positivity in University employees and health care workers (HCWs) in COVID-19- and non-COVID-19-units.

	University employees	HCWs in non-COVID-19-unit	HCWs in COVID-19-unit
Baseline characteristics	n = 192	n = 220	n = 51
Age, median (IQR)	44 (35–55)	37 (27–49)	39 (31–54)
Female, n %	104 (54%)	181 (82%)	39 (76%)
Comorbidities
Previously healthy, n %	164 (85%)	185 (84%)	43 (88%)
Cardiovascular disease, n %	14 (7%)	10 (5%)	4 (8%)
Pulmonary disease, n %	5 (3%)	17 (8%)	1 (2%)
Immunodeficiency, n %	7 (4%)	7 (3%)	0
Diabetes, n %	2 (1%)	3 (1%)	0
Current smoker, n %	8 (4%)	14 (6%)	9 (18%)
Occupation
Assistant nurse, n %	–	66 (30%)	23 (45%)
Nurse, n %	–	90 (40%)	20 (39%)
Physician, n %	–	30 (14%)	4 (8%)
Other HCWs with patient contact, n %	–	4 (2%)	1 (2%)
Other HCWs without patient contact, n %	–	30 (14%)	3 (6%)
University (non-HCWs), n %	192 (100%)	–	–
Hygiene routine adherence and nosocomial transmission
Poor adherence to hygiene recommendations in care of COVID-19-patients	–	17/141 (12%)	1/50 (2%)
Nosocomial COVID-19-transmission affecting patients at your ward	–	12/218 (6%)	1 (2%)
SARS-CoV-2
SARS-CoV-2-positivity, n %	11 (6%)	10 (5%)	11 (22%)
IgG, n %	11 (6%)	7 (3%)	9 (18%)
PCR, n %	0	6 (3%)	8 (16%)

Figure 1. Odds ratios for SARS-CoV-2-positivity in health care workers (HCW) (n = 192) by potential risk factors for exposure. An increased exposure situation was defined as a potentially aerosol generating procedure (e.g. intubation and airway handling including suctioning) or bedside surveillance for >3 h with a COVID-19-patient during a shift.

Table 2. Associations and odds ratios (OR) for SARS-CoV-2-positivity for hospital-related risk factors among health care workers (n = 271).

Potential exposure situations	SARS-CoV-2-positive with risk factor	SARS-CoV-2-positive without risk factor	p-Value	OR (95CI)	aOR (95CI)^b
Working at a COVID-19-unit	11/51 (22%)	10/220 (5%)	<.001	5.7 (2.1–16)	5.6 (1.3–23)
Caring for COVID-19-patients during a majority of days	12/61 (20%)	9/210 (4%)	<.001	5.4 (2.0–15)	5.1 (1.3–19)
Situation with increased exposure^a	9/56 (16%)	12/211 (6%)	.02	3.2 (1.1–8.7)	–
Worked with colleague who tested positive during your shift	7/62 (11%)	14/208 (7%)	.28	1.8 (0.57–4.9)	1.4 (0.45–4.0)

Bold indicates statistically significant differences and odds ratios with a significance level of <.05.

^aSituation with increased exposure include potentially aerosol generating procedures (e.g. intubation and airway handling including suctioning) or bedside surveillance for >3 h with a COVID-19-patient during a shift.

^bLogistic regression analyses were adjusted for the covariate ‘situation with increased exposure’ and adjusted OR (aOR) is provided.

Table 3. Associations and odds ratios (OR) for SARS-CoV-2-positivity for society-related risk factors among 463 participants (271 health care workers and 192 University employees).

Potential exposure situations	SARS-CoV-2-positive with risk factor	SARS-CoV-2-positive without risk factor	p-Value	OR (95CI)	aOR (95CI)^a
Confirmed COVID-19 case in the same household	4/10 (40%)	28/453 (6%)	<.01	10 (2.0–45)	11 (2.1–50)
Suspected COVID-19 case in the same household	8/57 (14%)	24/405 (6%)	.04	2.6 (0.95–6.4)	2.6 (0.94–6.3)
Workplace congestion	15/208 (7%)	17/252 (7%)	.87	1.1 (0.48–2.3)	0.82 (0.32–2.2)
Using public transport as transportation to work	23/305 (8%)	9/158 (6%)	.56	0.74 (0.29–1.7)	0.71 (0.28–1.6)
Travel within Sweden outside of living area	14/192 (7%)	18/271 (7%)	.85	1.1 (0.49–2.4)	1.1 (0.51–2.5)
International travel	6/121 (5%)	26/342 (8%)	.41	0.63 (0.21–1.6)	0.63 (0.20–1.6)

Bold indicates statistically significant differences and odds ratios with a significance level of <.05.

^aLogistic regression analyses were adjusted for the covariate health care worker status and adjusted OR (aOR) is provided.

Figure 2. Odds ratios for SARS-CoV-2-positivity in all participants (n = 463, health care workers and University employees) by potential risk factors for exposure.