Table 1.

Study subjects and seropositive participants by characteristics of the MERS case they were exposed to, and status of subjects upon MERS exposure in the 2015 Korean outbreak

	Characteristics of exposed MERS case	Status of subjects when they were exposed to MERS1							Selection or response rate (%)2
		Patient	Family	Visitor	Healthcare worker	Colleague	Unknown	Total
Quarantined subjects	Spreaders with 5 or more cases	1,141	71	417	558	3	657	2,847
	Spreaders with 1 to 4 cases	1,067	64	364	198	35	375	2,103
	Non-spreaders	3,489	321	1,613	1,260	453	2,745	9,881
	Total	5,697	456	2,394	2,016	491	3,777	14,831
Selected subjects	Spreaders with 5 or more cases	744	60	254	115	3	212	1,388	48.8
	Spreaders with 1 to 4 cases	191	10	105	10	0	29	345	16.4
	Non-spreaders	626	101	281	184	101	265	1,558	15.8
	Total	1,561	171	640	309	104	506	3,291	22.2
	Selection rate (%)	27.4	37.5	26.7	15.3	21.2	13.4	22.2
Study participants	Spreaders with 5 or more cases	252	53	152	94	1	0	552	39.8
	Spreaders with 1 to 4 cases	60	4	62	12	0	1	139	40.3
	Non-spreaders	262	109	271	201	50	26	919	59.0
	Total	574	166	485	307	51	27	1,610	48.9
	Response rate (%)	36.8	97.1	75.8	99.4	49.0	5.3	48.9
Subjects with seropositive ELISA (IFA/PRNT)	Spreaders with 5 or more cases	2 (1)			1 (0)			3 (1)
	Spreaders with 1 to 4 cases	1 (0)						1 (0)
	Non-spreaders	3 (0)						3 (0)
	Total	6 (1)			1 (0)			7 (1)
	Seropositive rate (%)	1.05 (0.17)			0.33 (–)			0.43 (0.06)

MERS, Middle East Respiratory Syndrome; ELISA, enzyme-linked immunospecific assay; IFA, immunofluorescence assay; PRNT, plaque reduction neutralization antibody test.

¹Inpatients or outpatients at a MERS-affected hospital, family of people living with or a paid caregiver of the MERS case, visitors of the hospitalized MERS case, healthcare workers employed at a MERS-affected hospital, and colleagues of co-workers of a MERS case.

²Selection rates varied by characteristics of the MERS case subjects were exposed to (i.e. transmission intensity) and the subjects’ status (i.e. exposure intensity).