Table 4. Risk factors of SFTS human-to-human transmission in China and South Korea, 1996–2019.

Factors	Contacts (No.)		Attack rate	Univariate analysis		Multivariate analysis
	Overall	Secondary case		P	OR (95%CI)	P	OR (95%CI)
Relationship
Blood relatives of index case	59	44	74.58%	<0.01	6.35(3.26–12.37)	N/A	N/A
	174	55	31.61%
Medical personnel	85	19	22.35%	<0.01	0.47(0.26–0.83)	N/A	N/A
	225	86	38.22%
Types of contact
Direct blood/bloody secretion contact	119	89	74.79%	<0.01	38.01(19.73–73.23)	<0.01	33.81(17.44–65.53)
	221	16	7.24%
Bloody droplet contact	57	34	59.65%	<0.01	4.41(2.44–7.99)	0.048	2.27(1.01–5.19)
	283	71	25.09%
Airborne contact	288	70	24.31%	<0.01	0.16(0.08–0.30)	N/A	N/A
	52	35	67.31%
Urine /Feces/Sweat contact	33	23	69.70%	<0.01	6.31(2.88–13.82)	N/A	N/A
	307	82	26.71%