Department of Rheumatology , Medical University of Vienna Vienna, Austria
Disclosure: Disclosure information not submitted.
Daniela Sieghart1, Daniel Mrak1, Elisabeth Simader1, Selma Tobudic2, Helga Radner1, Peter Mandl3, Lisa Göschl1, Maximilian Koblischke4, Nikolaus Hommer5, Lukas Hartl6, Philipp Hofer7, Felix Kartnig1, Thomas Hummel1, Andreas Kerschbaumer3, Thomas Deimel3, Antonia Puchner1, Renate Thalhammer8, Andreas Zuckermann9, Karin Stiasny4, Thomas Perkmann8, Helmuth Haslacher8, Markus Zeitlinger5, Ursula Wiedermann10, Judith Aberle4, Daniel Aletaha11, Leonhard Heinz1 and Michael Bonelli1, 1Division of Rheumatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria, 2Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria, 3Medical University of Vienna, Vienna, Austria, 4Center for Virology, Medical University of Vienna, Vienna, Austria, 5Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria, 6Division of Gastroenterology, Medical University of Vienna, Vienna, Austria, 7Department of Pathology, Medical University of Vienna, Vienna, Austria, 8Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria, 9Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria, 10Institute of Specific Prophylaxis and Tropical Medicine, Center of Pathophysiology, Infectiology & Immunology, Medical University Vienna, Vienna, Austria, 11Medical University Vienna, Wien, Austria
Background/Purpose: Patients under immunosuppressive therapy have a high risk for severe COVID-19 disease courses. However, efficacy of vaccination and therefore the right vaccination strategy remains unclear particularly in these individuals at risk.
The aim of the study was to investigate the efficacy of safety of a COVID-19 booster vaccination comparing homologous versus heterologous vaccination strategies in patients who did not seroconvert upon primary vaccination with an mRNA-based vaccine.
Methods: 75 patients under immunosuppressive treatment who received two doses of an mRNA vaccine with either BNT162b2 (Pfizer–BioNTech) or mRNA-1273 (Moderna) were screened. 51 patients without humoral immune response were randomized and of those 46 received a third dose of either the same mRNA or the vector vaccine ChAdOx1 nCoV-19 (Oxford-AstraZeneca). In this blinded clinical trial, the primary endpoint was defined as the difference in the SARS-CoV-2 antibody seroconversion rate four weeks after an additional booster vaccination with a heterologous (vector) versus homologous (mRNA) vaccine. Further endpoints included the overall seroconversion rate and cellular immune response; safety was evaluated until week four. SARS-CoV-2-specific T-cell responses were determined by ELISpot assay in patients and healthy controls. A paper-based patient diary was used to evaluate adverse events within the first week after vaccination.
Results: Seroconversion rates at week four were higher in the mRNA (15/24 patients, 63%) as compared to the vector vaccine groups (4/22 patients, 18%; p=0.006). Overall, 41% of patients seroconverted after an additional booster vaccination. SARS-CoV-2-specific T-cell responses were similarly increased after a third dose of either vector or mRNA vaccine. In a multivariable logistic regression analysis, patient age and vaccine type were associated with seroconversion. No serious adverse event was attributed to COVID-19 booster vaccination.
Conclusion: Homologous SARS-CoV-2 vaccination was found to be superior to a heterologous vaccination regimen and should be applied in non-seroconverted patients under immunosuppression.
Disclosures: D. Sieghart, None; D. Mrak, Pfizer; E. Simader, Boehringer-Ingelheim; S. Tobudic, None; H. Radner, None; P. Mandl, None; L. Göschl, None; M. Koblischke, None; N. Hommer, None; L. Hartl, None; P. Hofer, None; F. Kartnig, Boehringer-Ingelheim, Eli Lilly; T. Hummel, None; A. Kerschbaumer, AbbVie/Abbott, Eli Lilly, Gilead, Merck/MSD, Amgen, Janssen, UCB; T. Deimel, None; A. Puchner, None; R. Thalhammer, None; A. Zuckermann, None; K. Stiasny, Pfizer; T. Perkmann, None; H. Haslacher, Glock Health, BlueSky Immunotherapies, Neutrolis; M. Zeitlinger, None; U. Wiedermann, None; J. Aberle, None; D. Aletaha, Novartis, SoBi, Sanofi, Amgen, Lilly, Merck, Pfizer, Roche, Sandoz, Janssen, AbbVie; L. Heinz, None; M. Bonelli, Eli Lilly.
