A New Set-up of Vanishing Antibodies: A Biennial Follow-up of Five Different Clients’ Humoral Responses Against Sars-Cov-2 After Systemic Vaccination in an Oncology Hospital in Poland (preprint)

The humoral response of the COVID-19 vaccine varies from person to person. It largely depends on prior SARS-CoV-2 infection, obtaining an adequate immune response, and leaving a trace of changing antibody concentration over time. We retrospectively analyzed five clinical cases from selected patients and employees of the oncology hospital. All mild COVID-19 convalescents received the BNT162b2-Comirnaty mRNA vaccine three or four times. The levels of SARS-CoV-2 IgM- and IgG-specific antibodies, as well as S-RBD antibodies, were analyzed for two years. The concentration of antibodies was assessed in the laboratory using the chemiluminescent immunoassay CLIA, MAGLUMI. Results: (1) Active autoimmune disease stabilized the level of IgG-specific antibodies after systemic mRNA vaccination for at least six months. (2) Post-vaccination IgG and S-RBD levels decreased when vaccination was performed within three months of onset. (3) The booster dose administered only increased the S-RBD antibody levels. Declining IgG-specific antibodies were observed. (4) The S-RBD IgG levels were not correlated with the SARS-CoV-2 IgG levels in the vaccinated convalescents. (5) Subsequent reinfection with SARS-CoV-2 after vaccination three times released a more significant specific antibody response. Based on the collected data, we suggest that monitoring S-RBD antibodies is sensitive but not equivalent to a specific humoral response for SARS-CoV-2 IgG. We suggested that administering at least three doses of the mRNA vaccine should serve as the basis for immunization. The three-month interval may be the best alternative to an immunization schedule for non-immunocompromised people.

Systemic COVID-19 Vaccination also Enhances the Humoral Immune Response after SARS-CoV-2 Infection: A Population Study from a Hospital in Poland. Criteria for COVID-19 Reimmunization Are Needed (preprint)

Systemic vaccination with the BNT162b2 mRNA vaccine stimulates the humoral response.Our study aimed to compare the intensity of the humoral immune response, measured bySARS-CoV-2 IgG, SARS-CoV-2 IgM, and S-RBD neutralizing IgG antibody levels, afterCOVID-19 vaccination versus after SARS-CoV-2 infection. We analyzed 1060 people in thefollowing groups: convalescents, healthy vaccinated individuals, individuals vaccinated withComirnaty, AstraZeneca, Moderna, or Johnson & Johnson, and vaccinated SARS-CoV-2convalescents. The concentrations of SARS-CoV-2 IgG, SARS-CoV-2 IgM, and S-RBDneutralizing antibodies were estimated in the oncology hospital laboratory bychemiluminescent immunoassay (CLIA; MAGLUMI). Results: (1) We observed a rise inantibody response in both SARS-CoV-2 convalescent and COVID-19-vaccinated groups. (2)The levels of all antibody concentrations in vaccinated COVID-19 convalescents weresignificantly higher. (3) We differentiated asymptomatic SARS-CoV-2 convalescents from thecontrol group. Our analysis suggests that monitoring SARS-CoV-2 IgG antibodyconcentrations is essential as an indicator of asymptomatic COVID-19 and as a measure of theeffectiveness of the humoral response in convalescents and vaccinated people. Considering thetime-limited effects of post-SARS-CoV-2 infection recovery or vaccination and thephysiological half-life, among other factors, we suggest monitoring the IgG antibody level as acriterion for the next vaccination.