Table 2.

Overall proportion of HCW with (a) detectable antibodies, (b) history of past positive rRT-PCR, (c) Positive rRT-PCR at study recruitment, and (d) Cumulative prevalence of infection (past/current rRT-PCR and/or antibodies).

	n	Total	% (95% CI)	Not previously diagnosed as COVID-19 by rRT-PCR (n (%))	COVID19-symptoms reporteda n (%)
Seropositive to SARS CoV-2 Antibodies (IgA and/or IgM and/or IgG)	54	578	9.3% (7.1–12.0)	21 (38.9%)	10 (47.6%)
Positive rRT-PCR at study recruitmentb	15	576	2.6% (1.5–4.3)	6 (42.9%)	3 (50.0%)
Any evidence of past/current infection by rRT-PCR of serology	65	578	11.2% (8.8–14.1)	26 (40.0%)	12 (46.2%)

^aAmong those not previously diagnosed as COVID-19 (from previous column).

^bResults of 42 of the 578 rRT-PCRs done were invalid (Ct ≥ 40 for RNase P).