Further Important Characteristics of the SARS-CoV-2 IgG and IgA Antibody Response, Potentially Influencing Clinical Outcome: Immediate Antibody Degression and Dependency on Sex
25 Pages Posted: 21 Jul 2020More...
Background: For future progress on controlling the SARS-CoV-2 pandemic, an effective vaccine and/or herd immunity would be important goals. Both require a robust humoral immune response to raise sufficiently high titers of antibodies.
Methods: We repeatedly measured anti-nucleocapsid IgG and anti-spike IgG and IgA antibodies in 159 COVID-19 patients during a time course of two to ten weeks after PCR proven SARS-CoV-2 infection, reporting here in weekly intervals.
Findings: IgG were detected in in 93·5% to 95·4% of the patients at the peak of the antibody concentrations at week five after positive PCR. Thereafter, an immediate decline occurred in both IgG antibody types and became statistically significant by week eight (all p <0·012). The extent of the antibody response is associated to sex, with significantly higher concentrations observed in male patients (all p<0·0095). IgA showed a potential second wave after week eight, predominantly in men, which requires further clarification.
Interpretation: (Non-)control of the SARS-CoV-2 infection may depend on mechanisms beyond humoral response. The IgG decline immediately after reaching peak concentrations at week five is reason of concern, as an effective vaccine and/or herd immunity depend on a robust humoral response. The increased antibody concentrations observed in men might help to explain the worse clinical outcome in male COVID patients, e.g. through an increased inflammatory response.
Funding Statement: Center for Laboratory Medicine St. Gallen, Canton of St. Gallen
Declaration of Interests: No competing interests are reported.
Ethics Approval Statement: The study was registered with and approved by the regional ethics committee (ID2020-00941) and is registered in the Swissethics COVID 19 database (https://swissethics.ch/covid 19/approved-projects).
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