Table 1 D29 antibody marker response frequencies and geometric means by COVID-19 outcome status, for all geographic regions pooled as well as separately by geographic region

From: Neutralizing antibody correlate of protection against severe-critical COVID-19 in the ENSEMBLE single-dose Ad26.COV2.S vaccine efficacy trial

 

Severe-Critical COVID-19 Cases

Moderate COVID-19 Cases

Moderate to Severe-Critical COVID-19 Cases

Non-cases

Comparison: Severe-Critical COVID-19 Cases to Non-cases

Comparison: Moderate COVID-19 Cases to Non-cases

D29 Marker

N

Pos Resp Freq

GM (95% CI)

N

Pos Resp Freq

GM (95% CI)

N

Pos Resp Freq

GM (95% CI)

N

Pos Resp Freq

GM (95% CI)

Resp Freq Diff

(Cases –

Non-cases)

Ratio of GM

(Cases/

Non-cases)

Resp Freq Diff

(Cases –

Non-cases)

Ratio of GM

(Cases/

Non-cases)

All geographic regions pooled

nAb-ID50 (IU50/ml)

42

30.9% (18.5, 46.8%)

4.28 (3.15, 5.82)

332

39.7% (34.5, 45.1%)

5.02 (4.48, 5.63)

373

38.5% (33.7, 43.6%)

4.92 (4.42, 5.48)

774

46.1% (41.9, 50.4%)

6.06 (5.50, 6.67)

-15.2% (-28.3, 1.3%)

0.71 (0.51, 0.98)

-6.5% (-13.2, 0.4%)

0.83 (0.71, 0.96)

Spike IgG (BAU/ml)

42

80.9% (65.6, 90.4%)

29.35 (20.99, 41.05)

332

82.0% (77.4, 85.7%)

29.04 (25.92, 32.53)

373

81.8% (77.5, 85.4%)

28.98 (26.02, 32.28)

774

86.1% (83.0, 88.8%)

35.24 (32.23, 38.54)

-5.2% (-20.7, 4.8%)

0.83 (0.59, 1.18)

-4.2% (-9.4, 0.7%)

0.82 (0.71, 0.95)

RBD IgG (BAU/ml)

42

80.9% (65.6, 90.4%)

32.50 (24.00, 44.02)

332

78.4% (73.6, 82.5%)

28.65 (25.81, 31.80)

373

78.6% (74.1, 82.5%)

28.96 (26.23, 31.96)

774

81.9% (78.4, 85.0%)

33.49 (30.86, 36.34)

-1% (-16.6, 9.1%)

0.97 (0.71, 1.33)

-3.5% (-9.2, 1.9%)

0.86 (0.75, 0.98)

Latin America

nAb-ID50 (IU50/ml)

31

25.7% (13.0, 44.5%)

3.77 (2.74, 5.20)

258

40.7% (34.8, 46.8%)

5.28 (4.60, 6.05)

288

38.9% (33.4, 44.7%)

5.08 (4.47, 5.77)

197

52.7% (44.8, 60.5%)

7.03 (5.85, 8.44)

-27% (-41.9, -6.7%)

0.54 (0.37, 0.78)

-12% (-21.8, -2%)

0.75 (0.60, 0.94)

Spike IgG (BAU/ml)

31

80.6% (62.1, 91.3%)

29.65 (20.28, 43.35)

258

81.8% (76.5, 86.0%)

28.89 (25.34, 32.94)

288

81.6% (76.6, 85.7%)

28.85 (25.48, 32.66)

197

86.4% (80.7, 90.7%)

34.90 (29.87, 40.78)

-5.8% (-24.8, 6.3%)

0.85 (0.56, 1.28)

-4.7% (-11.4, 2.5%)

0.83 (0.68, 1.01)

RBD IgG (BAU/ml)

31

80.6% (62.1, 91.3%)

32.21 (22.90, 45.32)

258

78.6% (73.2, 83.2%)

28.36 (25.21, 31.91)

288

78.8% (73.7, 83.1%)

28.62 (25.60, 31.99)

197

84.0% (77.7, 88.8%)

33.80 (29.31, 38.96)

-3.4% (-22.5, 9.1%)

0.95 (0.66, 1.38)

-5.3% (-12.6, 2.5%)

0.84 (0.70, 1.01)

South Africa

nAb-ID50 (IU50/ml)

 

18

42.8% (21.3, 67.4%)

5.64 (3.36, 9.46)

181

43.2% (35.0, 51.8%)

6.18 (4.99, 7.65)

 

Spike IgG (BAU/ml)

18

84.0% (57.6, 95.3%)

35.44 (21.34, 58.87)

181

88.5% (82.4, 92.6%)

39.40 (32.89, 47.20)

RBD IgG (BAU/ml)

18

74.9% (46.4, 91.1%)

36.29 (21.07, 62.52)

181

84.7% (77.8, 89.7%)

36.29 (30.82, 42.72)

United States

nAb-ID50 (IU50/ml)

 

67

35.9% (25.1, 48.2%)

4.13 (3.45, 4.94)

396

41.3% (35.8, 46.9%)

5.31 (4.72, 5.97)

 

Spike IgG (BAU/ml)

67

82.1% (70.8, 89.7%)

27.87 (22.01, 35.29)

396

85.3% (80.7, 89.0%)

34.61 (30.56, 39.19)

RBD IgG (BAU/ml)

67

79.1% (67.5, 87.4%)

28.51 (22.80, 35.65)

396

79.5% (74.4, 83.9%)

32.61 (29.10, 36.55)

  1. Analysis based on baseline SARS-CoV-2 seronegative per-protocol vaccine recipients. Median (interquartile range) days from vaccination to D29 was 29 (2) for all regions pooled, 29 (2) for the United States, 29 (3) for Latin America, and 29 (2) for South Africa.
  2. BAU antibody binding units, CI confidence interval, GM geometric mean, IU international units, nAb-ID50 50% inhibitory dilution neutralizing antibody, Pos Resp Freq positive response frequency, RBD receptor binding domain, Resp Freq Diff response frequency difference.
  3. For the binding antibody assays, positive response was defined by having an IgG concentration above the specified positivity cut-off, with a separate cut-off for each antigen (10.8424 BAU/ml for Spike and 14.0858 BAU/ml for RBD; Table S10). Positive response for nAb-ID50 was defined by a D1 nAb-ID50 titer <LLOQ (LLOQ = 4.8975 IU50/ml) with quantifiable D29 nAb-ID50 ( ≥ LLOQ), or by D1 nAb-ID50 > LLOQ with at least a fourfold increase in D29 nAb-ID50.
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