| Author, Year | N | Time Since PCR+ or Symptom Onset | Antibody Type Tested: N Seronegative/N Tested (%) | Factors Tested for Association With Non-seroconversion | Statistically Significant Predictors of Non-seroconversion in Multivariable Analysis |
|---|---|---|---|---|---|
| Johannesen, 2021* | 886 | Median 131 days | Total antibody: 21/886 (2%) | BMI (<25, 25-30, >30), presence of symptoms (no or mild symptoms compared to clinically symptomatic and bedridden at home or at hospital) | No or mild symptoms: adjusted HR 6.6 (95% CI, 2.6-17), p<0.001 |
| Masia, 2021* | 132 | Median 6 days and up to 63 days | Total antibody, anti-N IgG, and anti-S IgG: 33/132 (25%) | Age, sex, Charlson comorbidity Index, clinical status (SOFA score, SpO2/FI02 on admission, and bilateral lung infiltrates on x-ray), microbiologic data, biomarkers, outcomes, anti-COVID-19 therapy |
Higher Ct of RT-PCR (indicating low viral load): adjusted OR 1.87 (95% CI, 1.09–3.21; p = .023) Higher Charlson comorbidity index: adjusted OR 1.35 (95% CI, 1.04–1.76; p = .027) Higher SpO2/FIO2 adjusted OR: 1.014 (95% CI, 1.00–1.02; p = .036) Higher neutrophil count: adjusted OR 1.38 (95% CI, 0.96–1.97; p = .081) Lower fibrinogen levels: adjusted OR 0.99 (95% CI, 0.99–1; p = .032) |
| Petersen, 2021 | 2547 | Mean 63.6 days (± 16.0) | Anti-S IgG: 160/2547 (6%) | Age group, sex, race/ethnicity, days since symptom onset, weight (under/normal, overweight, obesity, severe obesity), immunosuppressed, immunosuppressing therapies or medications, sought medical care, hospitalized, number of symptoms |
Immunosuppressive medications (31.9% lacking antibodies vs 6.2% for persons not taking such medications) Non-Hispanic White and Hispanic race/ethnicity (6.4% and 8.6%, respectively, lacking antibodies vs 2.7% for non-Hispanic Black race/ethnicity) Under/normal weight status (9.4% lacking antibodies vs 5.4% for obesity) Fewer symptoms (persons with 0-2 symptoms had higher risk of lacking antibodies compared with persons with 6-9 symptoms) |
| Staines, 2021 | 177 | Median 6 days (3-9) | Anti-S/N IgG:15/177 (8%) | Age (<70 or >70 years), sex, presence of respiratory symptoms, peak CRP levels, co-morbidities | No significant results in multivariable analysis |
| Thiruvengadam, 2021* | 743 | 6-10 weeks | Anti-RBD or anti-N IgG: 170/743 (23%) | Age (30-60 years and >60 years compared to 0-30 years), sex, comorbidities, presence or absence of symptoms at presentation |
Predictors of seroconversion: Older age: adjusted OR 1.03 (95% CI 1.02–1.05) Presence of symptoms at presentation: adjusted OR 3.23 (95% CI 2.01–5.17) |
| Wei, 2021* | 5230** | Median 221 days (14-251) | Anti-S IgG: 595/5230 (11%) | Age, sex, ethnicity, presence of long-term health conditions, working in patient-facing healthcare, Ct value, symptoms, have ≥PCR+ swab in the infection episode, days between first and last positive |
Higher minimum Ct: adjusted OR 1.33 (95% CI 1.31-1.36, p <0.001) Other symptoms compared to no symptoms: Adjusted OR 0.23, 95% CI 0.19-0.29, p<0.001 and adjusted OR classic symptoms compared to no symptoms 0.07, 95% 0.06-0.09, <0.001) Older age (OR NR) Not working in patient-facing healthcare: adjusted: OR working in patient-facing healthcare vs not 0.39, 95% CI 0.18-0.83, p< 0.01) |
New study for this update
Cohort with strong evidence for true-positive PCR: Ct ≤ 32 and ≥2 genes detected
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