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October 2023 - Daniel Mrak und Daniela Sieghart


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Dr. Daniel Mrak and DI (FH) Daniela Sieghart, PhD

MedUni Wien RESEARCHER OF THE MONTH October 2023

Impaired response to COVID-19 vaccination is of particular concern in immunosuppressed patients. We found that a critical number of patients did not develop antibodies against SARS-CoV-2 after two mRNA vaccinations (BNT162b2 or mRNA-1273). To determine the best vaccination strategy for this vulnerable group we performed a randomized blinded clinical trial. We could show that a third dose of the same mRNA vaccine led to increased seroconversion rates after 4 weeks compared to a booster vaccination with ChAdOx1 nCoV-19. The specific T-cell responses were reduced in immunosuppressed patients but could be increased after a third dose of either vector or mRNA vaccine. No serious adverse event was attributed to COVID-19 booster vaccination. Efficacy and safety data underline the importance of a booster vaccination and support the use of a homologous mRNA booster vaccination in immunosuppressed patients.

Selected Literature

  1. Mrak D, Tobudic S, Koblischke M, et al. SARS-CoV-2 vaccination in rituximab-treated patients: B cells promote humoral immune responses in the presence of T-cell-mediated immunity. Ann Rheum Dis 2021;80:1345–50. doi:10.1136/annrheumdis-2021-220781

  2. Bonelli M, Mrak D, Tobudic S, et al. Additional heterologous versus homologous booster vaccination in immunosuppressed patients without SARS-CoV-2 antibody seroconversion after primary mRNA vaccination: a randomised controlled trial. Ann Rheum Dis 2022;:annrheumdis-2021-221558. doi:10.1136/annrheumdis-2021-221558

  3. Mrak D, Sieghart D, Simader E, et al. Heterologous vector versus homologous mRNA COVID-19 booster vaccination in non-seroconverted immunosuppressed patients: a randomized controlled trial. Nat Commun 2022;13:5362. doi:10.1038/s41467-022-33036-y

  4. Mrak D, Simader E, Sieghart D, et al. Immunogenicity and safety of a fourth COVID-19 vaccination in rituximab-treated patients: an open-label extension study. Ann Rheum Dis 2022;:annrheumdis-2022-222579. doi:10.1136/ard-2022-222579

  5. Kartnig F, Mrak D, Simader E, et al. Safety and immunogenicity of a third COVID-19 vaccination in patients with immune-mediated inflammatory diseases compared with healthy controls. Annals of the Rheumatic Diseases Published Online First: 15 September 2022. doi:10.1136/ard-2022-222682

  6. Sieghart D, Hana CA, Haslacher H, et al. Multiparametric Prediction Models for Coronavirus Disease 2019 Vaccine Selection: Results of a Comparative Population-based Cohort Study. Clinical Infectious Diseases 2022;:ciac840. doi:10.1093/cid/ciac840

  7. Radner H, Sieghart D, Jorda A, et al. Reduced immunogenicity of BNT162b2 booster vaccination in combination with a tetravalent influenza vaccination: results of a prospective cohort study in 838 health workers. Clinical Microbiology and Infection Published Online First: 9 December 2022. doi:10.1016/j.cmi.2022.12.008

Dr. Daniel Mrak and DI (FH) Daniela Sieghart, PhD

Medizinische Universität Wien
Universitätsklinik für Innere Medizin III
Klinische Abteilung für Rheumatologie
Währinger Gürtel 18-20
1090 Wien

T: +43 (0) 1 40400-43010