1. Anti-spike protein to determine SARS-CoV-2 antibody levels: Is there a specific threshold conferring protection in immunocompromised patients?
- Author
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Halfon, Philippe, Jordana, Sylvie, Blachier, Stéphane, Cartlamy, Philippe, Kbaier, Laurent, Psomas, Christina K., Philibert, Patrick, Antoniotti, Gilles, Allemand-Sourrieu, Julie, Rebaudet, Stanislas, Cavaille, Guilhem, Stavris, Chloé, Retornaz, Frédérique, Chiche, Laurent, and Penaranda, Guillaume
- Subjects
IMMUNOCOMPROMISED patients ,SARS-CoV-2 ,IMMUNOGLOBULINS ,PRE-exposure prophylaxis ,NEUTRALIZATION tests - Abstract
Background: Identifying a specific threshold level of SARS-CoV-2 antibodies that confers protection in immunocompromised patients has been very challenging. The aim was to assess the threshold of 264 binding antibody units (BAU)/ml using four different SARS-CoV-2 antibody assays (Abbott, Beckman, Roche, and Siemens) and to establish a new optimal threshold of protection for each of the four antibody assays. Methods: This study was performed on data retrieved from 69 individuals, who received at least one dose of the Pfizer/BioNTech BNT162b2 or Moderna COVID-19 vaccine (Spikevax) at the Alphabio Laboratory in Marseille, France (European Hospital, Alphabio–Biogroup). The results were compared to the percent inhibition calculated using a functional surrogate of a standardized virus neutralization test (Genscript). Results: Samples from 69 patients were analyzed. For a reference cutoff of 264 BAU/ml, assays showed moderate to good overall concordance with Genscript: 87% concordance for Abbott, 78% for Beckman, 75% for Roche, and 88% for Siemens. Overall concordance increased consistently after applying new thresholds, i.e., 148 BAU/ml (Abbott), 48 (Beckman), 559 (Roche), and 270 (Siemens). Conclusion: We suggest specific adjusted thresholds (BAU/ml) for the four commercial antibody assays that are used to assess pre-exposure prophylaxis in immunocompromised patients. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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