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Table 2 Parametric estimates of latent and incubation periods of SARS-CoV-2 using Gamma distribution

From: Latent and incubation periods of Delta, BA.1, and BA.2 variant cases and associated factors: a cross-sectional study in China

 

Latent period (days)

 

Incubation period (days)

Delta (672)

Omicron (885)

BA.1 (208)

BA.2 (677)

 

Delta (405)

Omicron (420)

BA.1 (75)

BA.2 (345)

Mean

4.40 (4.24 ~ 4.63*)

2.58 (2.48 ~ 2.68)

2.50 (2.27 ~ 2.76)

2.58 (2.48 ~ 2.69)

 

5.04 (4.83 ~ 5.33)

3.41 (3.27 ~ 3.58)

3.42 (3.00 ~ 3.89)

3.39 (3.24 ~ 3.55)

Standard deviation

2.46 (2.32 ~ 2.65)

1.52 (1.43 ~ 1.61)

1.71 (1.48 ~ 1.95)

1.46 (1.36 ~ 1.56)

 

2.57 (2.37 ~ 2.79)

1.59 (1.47 ~ 1.72)

1.92 (1.54 ~ 2.34)

1.51 (1.38 ~ 1.65)

Median

3.95 (3.81 ~ 4.16)

2.28 (2.19 ~ 2.38)

2.12 (1.92 ~ 2.34)

2.32 (2.22 ~ 2.42)

 

4.61 (4.41 ~ 4.87)

3.17 (3.04 ~ 3.32)

3.07 (2.66 ~ 3.50)

3.17 (3.03 ~ 3.33)

25th percentile

2.59 (2.47 ~ 2.77)

1.46 (1.38 ~ 1.54)

1.24 (1.09 ~ 1.42)

1.51 (1.43 ~ 1.60)

 

3.16 (2.98 ~ 3.38)

2.25 (2.13 ~ 2.38)

2.01 (1.68 ~ 2.38)

2.29 (2.16 ~ 2.43)

75th percentile

5.72 (5.50 ~ 6.02)

3.38 (3.25 ~ 3.52)

3.35 (3.04 ~ 3.70)

3.37 (3.22 ~ 3.51)

 

6.46 (6.18 ~ 6.82)

4.31 (4.12 ~ 4.53)

4.45 (3.90 ~ 5.04)

4.25 (4.06 ~ 4.46)

95th percentile

9.07 (8.95 ~ 9.61)

5.48 (5.22 ~ 5.74)

5.81 (5.20 ~ 6.48)

5.36 (5.08 ~ 6.64)

 

9.87 (9.34 ~ 10.54)

6.38 (6.04 ~ 6.77)

7.06 (6.00 ~ 8.29)

6.20 (5.83 ~ 6.57)

97th percentile

10.04 (9.55 ~ 10.67)

6.09 (5.79 ~ 6.39)

6.54 (5.83 ~ 7.34)

5.93 (5.60 ~ 6.26)

 

10.85 (10.22 ~ 11.60)

6.97 (6.57 ~ 7.40)

7.82 (6.58 ~ 9.25)

6.74 (6.33 ~ 7.17)

98th percentile

10.79 (10.25 ~ 11.48)

6.57 (6.23 ~ 6.89)

7.11 (6.30 ~ 8.01)

6.38 (6.02 ~ 6.74)

 

11.60 (10.90 ~ 12.42)

7.41 (6.98 ~ 7.90)

8.40 (7.02 ~ 9.97)

7.16 (6.71 ~ 7.64)

99th percentile

12.03 (11.41 ~ 12.83)

7.36 (6.97 ~ 7.75)

8.07 (7.08 ~ 9.14)

7.12 (6.70 ~ 7.55)

 

12.84 (12.02 ~ 13.79)

8.16 (7.65 ~ 8.71)

9.38 (7.79 ~ 11.23)

7.85 (7.33 ~ 8.41)

  1. Notes *95% confidence interval