Scientific Reports (Dec 2024)

Direct detection of 4-dimensions of SARS-CoV-2: infection (vRNA), infectivity (antigen), binding antibody, and functional neutralizing antibody in saliva

  • Aida Mohammadi,
  • Samantha Chiang,
  • Feng Li,
  • Fang Wei,
  • Chang S. Lau,
  • Mohammad Aziz,
  • Francisco J. Ibarrondo,
  • Jennifer A. Fulcher,
  • Otto O. Yang,
  • David Chia,
  • Yong Kim,
  • David T.W. Wong

DOI
https://doi.org/10.1038/s41598-024-81019-4
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 15

Abstract

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Abstract We developed a 4-parameter clinical assay using Electric Field Induced Release and Measurement (EFIRM) technology to simultaneously assess SARS-CoV-2 RNA (vRNA), nucleocapsid antigen, host binding (BAb) and neutralizing antibody (NAb) levels from a drop of saliva with performance that equals or surpasses current EUA-approved tests. The vRNA and antigen assays achieved lower limit of detection (LOD) of 100 copies/reaction and 3.5 TCID₅₀/mL, respectively. The vRNA assay differentiated between acutely infected (n = 10) and infection-naïve patients (n = 33) with an AUC of 0.9818, sensitivity of 90%, and specificity of 100%. The antigen assay similarly differentiated these patient populations with an AUC of 1.000. The BAb assay detected BAbs with an LOD of 39 pg/mL and distinguished acutely infected (n = 35), vaccinated with prior infection (n = 13), and vaccinated infection-naïve patients (n = 13) from pre-pandemic (n = 81) with AUC of 0.9481, 1.000, and 0.9962, respectively. The NAb assay detected NAbs with a LOD of 31.6 Unit/mL and differentiated between COVID-19 recovered or vaccinated patients (n = 31) and pre-pandemic controls (n = 60) with an AUC 0.923, sensitivity of 87.10%, and specificity of 86.67%. Our combo assay represents a significant technological advancement to simultaneously address SARS-CoV-2 infection and immunity, and it lays the foundation for tackling potential future pandemics.