Table 2 Summary of pre-calibration ID50 and ID80 titers measured by the Duke and Monogram labs and their fold-differences for convalescent patient sera, Day 29 vaccinee sera, Day 57 vaccinee sera, and the WHO International Standard sample.

From: Calibration of two validated SARS-CoV-2 pseudovirus neutralization assays for COVID-19 vaccine evaluation

 

Convalescent (n = 248)

Vaccine Day 29 (n = 30)

Vaccine Day 57 (n = 30)

Vaccine Day 57 versus Day 29

WHO International Standard

ID50

Duke

 Mean (SD)*

607.3 (1.6)

65.7 (0.8)

1463.5 (1.1)

22.3 (1.1)

3046.7 (0.8)

 Median

581.0

72.5

1547.0

22.4

2421.5

 Range

23.0–32,362.0

13.0–456.0

15.0–4714.0

0.5 – 158.4

957.0–11,101.0

 Response Rate**

99%

100%

100%

NA

100%

Monogram

  Mean (SD)*

1692.0 (1.4)

178.3 (1.0)

4120.7 (1.0)

23.1 (1.1)

14,997.5 (0.2)

 Median

1604.0

219.5

5274.0

23.5

16,133.0

 Range

72.0–100,563.0

20.0–1222.0

62.0–16,280.0

0.4 – 163.2

10,044.0–21,785.0

 Response Rate**

100%

90%

100%

NA

100%

Monogram versus Duke fold difference

 Mean (SD)*

2.8 (0.7)

2.7 (0.4)

2.8 (0.4)

NA

4.9 (NA)

 Median

3.0

2.8

2.7

 

6.7

 Range

0.3–26.0

1.0–7.1

1.2–6.3

 

2.0–10.5

ID80

Duke

 Mean (SD)*

103.7 (1.6)

16.2 (0.8)

330.5 (0.9)

20.3 (0.9)

566.7 (0.6)

 Median

94.5

19.5

421.5

22.7

489.0

 Range

10.0–5078.0

5.0–91.0

5.0–1255.0

1.0–112.0

250.0–1391.0

 Response Rate**

83%

77%

97%

NA

100%

Monogram

 Mean (SD)*

536.8 (1.4)

60.9 (0.8)

1522.5 (1.0)

25.0 (1.1)

4259.7 (0.2)

 Median

504.5

82.0

1758.5

27.5

4062.5

 Range

20.0–32,557.0

20.0–393.0

20.0–5984.0

0.5–130.5

2950.0–6892.0

 Response Rate**

98%

70%

97%

NA

100%

Monogram versus Duke fold difference

 Mean (SD)*

5.2 (0.7)

3.7 (0.5)

4.6 (0.2)

NA

7.5 (NA)

 Median

5.1

4.0

4.5

 

8.3

 Range

0.4–75.2

1.3–15.0

2.9–7.8

 

5.0–11.8

  1. *Geometric mean of titers or titer ratios and standard deviation of the loge-transformed titers or titer ratios.
  2. **Proportion of samples with an ID50 or ID80 titer above the assay LLoD.