Evaluation of the Roche SARS-CoV-2 Rapid Antibody Test in Samples from Vaccinated Individuals

Abstract

The study aimed to establish the performance of the SARS-CoV-2 Rapid Antibody Test (IgG and IgM) and the Elecsys Anti-SARS-CoV-2 S assay in vaccinated individuals. A panel of serum samples from Boca Biolistics was utilized to assess antibodies following vaccination, consisting of samples drawn prior to vaccination, after the first dose, or at least 14 days after the second dose of Moderna mRNA-1273 or Pfizer-BioNTech BNT162b2 COVID-19 vaccines. Agreement between the two methods was measured and stratified by test evaluator and assay lot. Agreement between the SARS-CoV-2 Rapid Antibody Test (IgG) and Elecsys Anti-SARS-CoV-2 S assay qualitative measurements at the different assessment points for both mRNA-1273 and BNT162b2 ranged between 97.06% (95% confidence interval [CI] 84.67, 99.93) to 100% (95% CI 82.35, 100). Agreement of the SARS-CoV-2 Rapid Antibody Test (IgG) with the Elecsys Anti-SARS-CoV-2 S assay was not highly influenced by either lot or evaluator. There was a medium-to-strong correlation between the semiquantitative SARS-CoV-2 Rapid Antibody Test (IgG) result and quantitative Elecsys Anti-SARS-CoV-2 S assay in samples taken after both doses of the vaccines, with higher intensity bands being associated with higher total anti-S antibody titer (mRNA-1273, P = 0.0019; BNT162b2, P < 0.0001). Conclusion Semiquantitative SARS-CoV-2 Rapid Antibody Test (IgG) and quantitative Elecsys Anti-SARS-CoV-2 S assay correlated well, suggesting that the SARS-CoV-2 Rapid Antibody Test (IgG) is helpful in understanding the immune response postvaccination. The current data support the use of the SARS-CoV-2 Rapid Antibody Test (IgG) in the vaccinated population. IMPORTANCE Serologic assays are an essential tool for seroprevalence surveys, for quality control of vaccines, and to determine the response to vaccination. Although a correlate of immunity has not yet been established for COVID-19 vaccines, antibody titers after natural infection and vaccination have been associated with protection from symptomatic SARS-CoV-2 infection. Rapid point-of-care assays can be of use in this context with advantages over centralized testing, such as speed and ease of use. The point-of-care SARS-CoV-2 Rapid Antibody Test (IgG) compared favorably to the Elecsys Anti-SARS-CoV-2 S assay with agreement rates above 97.06%, after one or two doses of Moderna mRNA-1273 or Pfizer-BioNTech BNT162b2. Semiquantitative SARS-CoV-2 Rapid Antibody Test (IgG) and quantitative Elecsys Anti-SARS-CoV-2 S assay results correlated well, suggesting that SARS-CoV-2 Rapid Antibody Test (IgG) is helpful in understanding the immune response postvaccination. The current data support the use of the SARS-CoV-2 Rapid Antibody Test (IgG) in the vaccinated population.

Keywords: COVID-19 vaccines; SARS-CoV-2; antibodies; immunity; immunoassay; neutralizing; nucleocapsid protein; point-of-care systems; spike protein.

FIG 1

SARS-CoV-2 Rapid Antibody Test semiquantitative IgG versus Elecsys Anti-SARS-CoV-2 S assay total antibody titer following vaccination with Moderna mRNA-1273 (left panel) or Pfizer-BioNTech BNT162b2 (right panel) at least 14 days following second dose. Results from the SARS-CoV-2 Rapid Antibody Test were classified as negative or one of the five levels of increasing positivity based upon line intensity (((+)), (+), +, ++ or +++). Maximum value attainable by the Elecsys Anti-SARS-CoV-2 assay was 25,000 U/mL. Higher values are indicated as >25,000 U/mL. Blue = Lot 1; red = Lot 2; ○ = Evaluator 1; + = Evaluator 2.

FIG 2

SARS-CoV-2 Rapid Antibody Test semiquantitative IgM versus Elecsys Anti-SARS-CoV-2 S assay total antibody titer following vaccination with Moderna mRNA-1273 (left panel) or Pfizer-BioNTech BNT162b2 (right panel) at least 14 days following second dose. Results from the SARS-CoV-2 Rapid Antibody Test were classified as negative or one of the five levels of increasing positivity based upon line intensity (((+)), (+), +, ++ or +++). Maximum value attainable by the Elecsys Anti-SARS-CoV-2 assay was 25,000 U/mL. Higher values are indicated as >25,000 U/mL. Blue = Lot 1; red = Lot 2; ○ = Evaluator 1; + = Evaluator 2.

FIG 3

Elecsys Anti-SARS-CoV-2 S assay total antibody titer over time following vaccination with Moderna mRNA-1273 or Pfizer-BioNTech BNT162b2 (second dose). Maximum value attainable by the Elecsys Anti-SARS-CoV-2 assay was 25,000 U/mL. Higher values are indicated as >25,000 U/mL. Blue = mRNA-1273; red = BNT162b2.