biostudies-literatureAffeldt PMinistry of Science North Rhine-Westphalia and the German Research Foundation2646https://www.ebi.ac.uk/biostudies/studies/S-EPMC9785871biostudies-literatureUnknown14(12)Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a serious hazard for hemodialysis (HD) patients and kidney transplant (KTX) recipients as they suffer from an impaired immune response to SARS-CoV-2 vaccination. In addition, a definition of SARS-CoV-2 IgG titer that indicates a sufficient immune response, especially against new omicron variants, is urgently needed. In the present study, the immune response to either a third or a fourth dose of a mRNA vaccine was investigated in 309 dialysis and 36 KTX patients. SARS-CoV-2 IgG titer thresholds indicating neutralizing activity against wild type (WT) and the omicron variant BA.1 were quantified. After four vaccine doses, a high-neutralizing activity against WT was evidenced in HD patients, whereas the neutralizing rate agaiVirusesImmune Response to Third and Fourth COVID-19 Vaccination in Hemodialysis Patients and Kidney Transplant Recipients.PMC9785871DFG, DI 1501/9-2, MU 3629/6-1Muller RUOehm SGies MAffeldt PHeger EPlaten EBrensing KAHinrichs SStippel DKlein FKurschat CWirtz MBenzing TKoehler FCButt LDi Cristanziano VGrundmann FAdam VKalisch NSteger GfalseImmune Response to Third and Fourth COVID-19 Vaccination in Hemodialysis Patients and Kidney Transplant Recipients.Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a serious hazard for hemodialysis (HD) patients and kidney transplant (KTX) recipients as they suffer from an impaired immune response to SARS-CoV-2 vaccination. In addition, a definition of SARS-CoV-2 IgG titer that indicates a sufficient immune response, especially against new omicron variants, is urgently needed. In the present study, the immune response to either a third or a fourth dose of a mRNA vaccine was investigated in 309 dialysis and 36 KTX patients. SARS-CoV-2 IgG titer thresholds indicating neutralizing activity against wild type (WT) and the omicron variant BA.1 were quantified. After four vaccine doses, a high-neutralizing activity against WT was evidenced in HD patients, whereas the neutralizing rate agai2022-01-01T00:00:00Z2022 Nov2025-04-18T15:59:52.741Z2025-04-07T02:57:08.903ZS-EPMC97858713656064810.3390/v14122646