Table 3. Case-control study 2: Exposures associated with risk of COVID-19 among HCWs taking care of non COVID-19 positive patients.

Characteristics	Cases* (n = 84)	Controls* (n = 336)	OR [95% CI]	ORa [95% CI]
Age (years)
< 30	17 (20.2)	66 (19.6)	1 (ref)
30–39	25 (29.8)	103 (30.7)	0.95 [0.75–1.19]
40–49	23 (27.4)	103 (30.7)	0.94 [0.73–1.20]
≥ 50	19 (22.6)	64 (19.0)	1.05 [0.80–1.36]
Sex
Women	72 (85.7)	284 (84.5)	1 (ref)
Men	12 (14.3)	52 (15.5)	0.91 [0.72–1.15]
Preventative measures (PPE wearing and other)
Handrubbing with alcohol based handrub before and after patient care
Never/rarely	0 (0)	17 (5.1)	-
Regularly/always	84 (100)	319 (94.9)	-
Type of mask used
Mainly surgical masks	60 (71.4)	245 (72.9)	1 (ref)	1 (ref)
Surgical masks + respirators during aerosol-generating procedures	19 (22.6)	78 (23.2)	1.01 [0.83–1.21]	0.81 [0.66–1.00]
Mainly respirators	5 (6.0)	13 (3.9)	2.36 [1.45–4.00]	1.84 [1.06–3.37]
Face shield or protective goggles
Never/rarely	76 (90.5)	327 (97.3)	1 (ref)	1 (ref)
Regularly/always	8 (9.5)	9 (2.7)	3.78 [2.34–9.97]	3.10 [1.81–5.58]
Disposable gown and plastic apron when needed
Never/rarely	62 (73.8)	273 (81.2)	1 (ref)	1 (ref)
Regularly/always	22 (26.2)	63 (18.8)	1.59 [1.29–1.96]	1.22 [0.93–1.57]
Gloves, for all types of patient care
Never/rarely	34 (40.5)	167 (49.7)	1 (ref)	1 (ref)
Regularly/always	50 (59.5)	169 (50.3)	1.56 [1.29–1.88]	1.36 [1.10–1.68]
Protective hair cap
Never/rarely	79 (94.0)	321 (95.5)	1 (ref)
Regularly/always	5 (6.0)	15 (4.5)	1.33 [0.91–2.06]
Protective overshoes
Never/rarely	83 (98.8)	331 (98.5)	1 (ref)
Regularly/always	1 (1.2)	5 (1.5)	0.73 [0.40–1.40]
Regular airing of patients/residents’ rooms
Never/rarely	28 (33.3)	124 (36.9)	1 (ref)
Regularly/always	56 (66.7)	212 (63.1)	1.19 [0.99–1.42]

OR: Odds ratio. ORa: Adjusted odds ratio.

* Cases and controls were matched on workplace and occupation.