Table 1.

Summary of data.

papers	country	no. of included (excluded) cases	site of viral load data used	reporting value	detection limit (copies ml–1)	range of symptom onset	agec	sex (M : F)
Young et al. [40]	Singapore	12 (6)	nasopharyngeal swab	cycle thresholda	68.0	1/21–1/30	37.5 (31–56)	6 : 6
Zou et al. [39]	China	8 (8)	nasal swab	cycle thresholda	15.3	1/11–1/26	52.5 (28–78)	3 : 5
Kim et al. [41]	Korea	2 (7)	nasopharyngeal and oropharyngeal swab	cycle thresholda	68.0	NA	NA	NA
Wölfel et al. [21]	Germany	8 (1)	pharyngeal swab	viral load (copies/swab)b	33.3	1/23–2/4	NA	NA

^acycle threshold values were converted by using the formula: log₁₀(viral load [copies ml⁻¹]) = −0.32 × Ct values [cycles] + 14.11 [39].

^b1 swab was assumed to be 3 ml in Wölfel et al. according to the original paper.

^cmedian (range).