Table E4.

Characterization of 10 seronegative subjects with SARS-CoV-2 memory B- and T-cell responses

Characteristic	1A	2B	3C	4D	5E	6F	7G	8H	9I	10J
Cellular memory immunity
Memory B-cell response	No	Yes	No	No	No	No	No	No	Yes	No
Memory T-cell response∗	Yes	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Antibody titers†‡ (cutoff/borderline/median)
IgG (25.1/22.5/6.5 AU/mL)	9.7‡	6.6‡	8.6‡	7.5‡	3.1	11.5‡	9.2‡	16.2‡	23.2†	9.6‡
IgM (14.4/7.8/3.0 AU/mL)	3.7‡	7.0‡	4.3‡	4.6‡	2.5	6.5‡	2.2	11.2†	10.5†	3.7‡
IgA (2.6/1.4/0.1 AU/mL)	0	0	2.1†	0	0	0	1.1‡	0.5‡	2.1†	0.0
Symptoms
Any symptoms Feb 20 to Jan 21	Yes	No	Yes	No	No	Yes	Yes	Yes	Yes	No
Time from symptoms to clinical visit§	0	NA	0	NA	NA	2	8	10	1	NA
Other factors
Self-reported positive PCR test	No	No	No	No	No	No	No	No	Yes	No
COVID-19 in household‖	No	No	Yes	No	No	No	Yes	No	Yes	Yes

Participant cohort identification numbers are renamed by 1 number and 1 letter that cannot be connected to original identification numbers. NA, Not applicable.

^∗Positive in at least 1 T-cell assay.

^†Bordeline positive antibody titer.

^‡Titer exceeding median antibody titer value in seronegative group.

^§Time in months between latest episode of reported symptoms and clinical visit.

^‖Suspected or confirmed COVID-19 disease in household.