Table 3.
Associations Between SARS-CoV-2 IgG Antibody Responses and Elevated SARS-CoV-2 Neutralizing Antibody Titers
| Outcome | ||||
|---|---|---|---|---|
| Univariable Models | Multivariable Models | |||
| Serologic Biomarker | PR (95% CI) | P Value | aPR (95% CI) | P Value |
| Neutralizing Antibody Titer AUC value ≥ 160 | ||||
| Anti-spike IgG titers, AU | 1.57 (1.42–1.74) | < .001 | 1.61 (1.43–1.81) | < .001 |
| Anti-spike IgG avidity, DC50 | 1.80 (1.45–2.22) | < .001 | 1.58 (1.19–2.12) | .002 |
| log2 anti-nucleocapsid IgG titer, ODn | 7.02 (3.64–13.56) | < .001 | 10.43 (4.65–23.41) | < .001 |
| log2 anti-nucleocapsid IgG avidity, DC50 | 2.80 (.73–10.75) | .133 | 1.57 (.40–6.18) | .516 |
| Neutralizing Antibody Titer AUC value ≥ 40 | ||||
| Anti-spike IgG titers, AU | 1.24 (1.17–1.31) | < .001 | 1.24 (1.15–1.33) | < .001 |
| Anti-spike IgG avidity, DC50 | 1.31 (1.16–1.48) | < .001 | 1.18 (.99–1.41) | .064 |
| log2 anti-nucleocapsid IgG titer, ODn | 2.01 (1.56–2.49) | < .001 | 2.25 (1.66–3.04) | < .001 |
| log2 anti-nucleocapsid IgG avidity, DC50 | 1.67 (.84–3.32) | .140 | 1.42 (.77–2.64) | .264 |
Prevalence ratios of a neutralizing titer AUC value ≥160 and ≥40 were estimated from Poisson regression models with robust standard errors. A different model was used for each serologic biomarker shown. Multivariable models were used to estimate adjusted prevalence ratios which included adjustment for age, sex, hospitalization, and time from symptom onset. Values bolded indicate statistical significance (P < .05).
Abbreviations: aPR, adjusted prevalence ratio; AU, arbitrary unit; AUC, area under curve; CI, confidence interval; DC50, 50% dissociation constant; ODn, normalized optical density; PR, prevalence ratio.