Assessment and Comparison of Two Serological Approaches for the Surveillance of Health Workers Exposed to SARS-CoV-2

Figures & data

Figure 1 Study design.

Table 1 Result of LFAs in Different Settings

Setting	N° Sample	LFA Negative	LFA Positive	Sensitivity (%) (95% CI)	Specificity (%) (95% CI)
Negative Control	30	30	0	–	100 (88.43–100.00)
Positive control	32	3	29	90.65 (74.98–98.02)	–
Health workers*	65	59	6		90.77 (80.98–96.54)
HW population**	196	176	20	–	89.80 (84.68–93.65)
Negative control + Health workers	283	263	20	–	89.30 (89.30–95.63)

Notes: *HWs were defined positive, if tested positive in at least at one sample; HWs were defined negative, if tested negative in all samples. **Considering all tests performed over HWs population.

Abbreviation: LFAs, lateral-flow assays.

Table 2 Results of ELISA Tests in Different Settings

Setting	N° Sample	ELISA Negative	ELISA Positive	Sensitivity (%) (95% CI)	Specificity (%) (95% CI)
Negative Control	30	30	0	–	100 (88.43–100.00)
Positive control	32	1	31	96.88 (83.78–99.92)	–
Health workers*	65	65	0		100 (94.48–100.00)
HW population**	196	196	0	–	100 (98.14–100.00)
Negative control + Health workers	283	283	0	–	100 (98.70–100.00)

Notes: *HWs were defined positive, if tested positive in at least at one sample; HWs were defined negative, if tested negative in all samples. **Considering all tests performed over HWs population.

Abbreviation: ELISA, enzyme-linked immunosorbent assay.

Table 3 Description of HWs Enrolled

HWs Enrolled	65
Males (n,%)	25 (38,5%)
Females (n,%)	40 (61.5%)
Age (median, IQR)	32 (28–43)
Role:
Physician (n,%)	25 (38.5%)
Nurse (n,%)	35 (53.8%)
Patient-care technician (n,%)	5 (7.7%)
Type of exposure to COVID-19 patients:
Direct care to patient (n,%)	64 (98.5%)
Contact with patient or patient’s environment without direct care (n, %)	1 (1.5%)
Participation in training about PPE procedures:
Yes (n,%)	65 (100%)
No (n,%)	0 (0%)
HWs enrolled with fever or cough during the study period	0 (0%)
HWs reporting deviation from protocol procedures	0 (0%)
HWs reporting contact with COVID-19 patients without PPE	0 (0%)

Abbreviations: PPE, personal protective equipment; HWs, health workers.