Table 2: Probability (mean ± standard deviation) of HCV transmission as a function of viral load.

To estimate the probability of HCV transmission (Eq. 1) means were calculated using a Monte Carlo procedure. For parameter ρ (Eq. 1), samples were generated using the truncated normal distribution with the standard deviation equal to ¼ of the experimentally determined range. For parameter s, values were chosen from a uniform distribution between 0.05 and 0.5, and q values were chosen from a gamma distribution with calculated median and Q1-Q3 as 17% and 7%−33%, respectively, (table S2). HDSS, high dead space syringe; LDSS, low dead space syringe.

	Mean HCV transmission probability (± SD)
	LDSS		HDSS
HCV titer [log10 IU/mL]	Unrinsed	Rinsed	Unrinsed	Rinsed
1.0	0.57(±1.25)	0.16(±0.30)	2.58(±4.16)	0.30(±0.55)
1.5	1.78(±3.53)	0.51(±0.96)	7.58(±10.36)	0.97(±1.72)
2.0	5.43(±8.60)	1.67(±3.00)	19.97(±20.84)	3.09(±5.10)
2.5	14.12(±17.34)	4.89(±7.85)	40.81(±30.08)	8.66(±12.00)
3.0	31.00(±28.03)	12.95(±16.67)	65.67(±31.68)	21.18(±22.10)
3.5	54.04(±33.41)	28.73(±27.39)	84.54(±25.09)	42.25(±30.94)
4.0	75.50(±30.68)	50.95(±33.81)	94.26(±16.41)	66.45(±32.01)
4.5	88.90(±23.29)	72.52(±31.79)	98.04(±9.78)	84.66(±25.26)
5.0	95.31(±15.79)	87.22(±24.31)	99.37(±5.73)	94.12(±16.89)
5.5	98.13(±10.09)	94.79(±16.41)	99.78(±3.29)	97.89(±10.19)
6.0	99.30(±6.03)	97.91(±11.36)	99.94(±1.25)	99.31(±6.11)