Table 1 D35 antibody marker SARS-CoV-2 seroresponse rates and geometric means in the U.S. cohort by COVID-19 outcome status

From: Immune correlates analysis of the PREVENT-19 COVID-19 vaccine efficacy clinical trial

D35 Marker

COVID-19 Casesa

Non-Cases in Immunogenicity Subcohortb

Comparison

N

Proportion with Antibody Responsec (95% CI)

Geometric Mean (GM) (95% CI)

N

Proportion with Antibody Responsec (95% CI)

Geometric Mean (GM) (95 % CI)

Response Rate Difference (Non-Cases–Cases)

Ratio of GM (Non-Cases/Cases)

Anti Spike IgG (BAU/ml)

12

91.7% (52.5%, 99.1%)

528 (184, 1513)

639

99.6% (99.2%, 99.8%)

1552 (1407, 1713)

8.0% (0.5%, 47.2%)

2.9 (1.0, 8.3)

Anti RBD IgG (BAU/ml)

12

91.7% (52.5%, 99.1%)

722 (270, 1931)

639

98.5% (97.1%, 99.2%)

2123 (1904, 2369)

6.8% (−0.7%, 46%)

2.9 (1.1, 7.7)

Pseudovirus-nAb ID50 (IU50/ml)

12

83.3% (47.6%, 96.5%)

135 (35, 519)

639

98.8% (97.5%, 99.4%)

461 (404, 526)

15.4% (2.2%, 51.2%)

3.4 (0.9, 12.5)

  1. aCases are baseline SARS-CoV-2 seronegative per-protocol vaccine recipients with the primary COVID-19 endpoint (symptomatic RT-PCR-confirmed COVID-19) starting 7 days post D35 visit through to the data cut (April 19, 2021).
  2. bNon-cases are baseline negative per-protocol vaccine recipients sampled into the immunogenicity subcohort with no evidence of SARS-CoV-2 infection (i.e., never tested RT-PCR positive) up to the end of the correlates study period (the data cut-off date April 19, 2021).
  3. cAntibody response defined by IgG concentration above the assay positivity cut-off (10.8424 BAU/ml) or by detectable ID50 > limit of detection (LOD) = 2.612 IU50/ml.
  4. Analysis based on baseline SARS-CoV-2 negative per-protocol vaccine recipients in the case-cohort set. Median (interquartile range) days from vaccination to D35 was 38 (6).
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