Background Dialysis patients are at risk for lower SARS-CoV-2-vaccine immunogenicity than the normal population. We assessed immunogenicity to a first mRNA- or vector-based SARS-CoV-2-vaccination dose in dialysis patients. Methods In a multicenter observational pilot study, 2 weeks after a first vaccination (BNT162b2/Pfizer-BioNTech [Comirnaty] or ChAdOx1 nCoV-19/Oxford-Astra-Zeneca [Vaxzevria]), hemodialysis patients (N = 23), peritoneal dialysis patients (N = 4) and healthy staff (N = 14) were tested for SARS-CoV-2-spike IgG/IgM, Nucleocapsid-protein-IgG-antibodies and plasma ACE2-receptor-binding-inhibition capacity. Hemodialysis patients who had had prior COVID-19 infection (N = 18) served as controls. Both response to first SARS-CoV-2 vaccination and IgG spike-positivity following prior COVID-19 infection were defined as SARS-CoV-2 spike IgG levels ≥ 50 AU/mL. Results Vaccination responder rates were 17.4% (4/23) in hemodialysis patients, 100% (4/4) in peritoneal dialysis patients and 57.1% (8/14) in staff (HD vs. PD: p = 0.004, HD vs. staff: p = 0.027). Among hemodialysis patients, type of vaccine (Comirnaty N = 11, Vaxzevria N = 12, 2 responders each) did not appear to influence antibody levels (IgG spike: Comirnaty median 0.0 [1.–3. quartile 0.0–3.8] versus Vaxzevria 4.3 [1.6–20.1] AU/mL, p = 0.079). Of responders to the first dose of SARS-CoV-2 vaccination among hemodialysis patients (N = 4/23), median IgG spike levels and ACE2-receptor-binding-inhibition capacity were lower than that of IgG spike-positive hemodialysis patients with prior COVID-19 infection (13/18, 72.2%): IgG spike: median 222.0, 1.–3. quartile 104.1–721.9 versus median 3794.6, 1.–3. quartile 793.4–9357.9 AU/mL, p = 0.015; ACE2-receptor-binding-inhibition capacity: median 11.5%, 1.–3. quartile 5.0–27.3 versus median 74.8%, 1.–3. quartile 44.9–98.1, p = 0.002. Conclusions Two weeks after their first mRNA- or vector-based SARS-CoV-2 vaccination, hemodialysis patients demonstrated lower antibody-related response than peritoneal dialysis patients and healthy staff or unvaccinated hemodialysis patients following prior COVID-19 infection. Graphic abstract

Background After the reports of severe adverse reactions to the AstraZeneca ChAdOx1-S-nCoV-19 vaccine, patients who had received one dose of ChAdOx1-S-nCoV-19 vaccine were recommended a second dose of Pfizer’s BNT162b2 vaccine. In hemodialysis patients, we compared the humoral immunogenicity and tolerability of homologous vaccination with ChAdOx1-nCoV-19/ChAdOx1-nCoV-19 (ChAd/ChAd) and BNT162b2/BNT162b2 (BNT/BNT) with heterologous vaccination of first dose of ChAdOx1-nCoV-19 and a second dose with BNT162b2 (ChAd/BNT). Methods In a multicenter prospective observational study, SARS-CoV-2 spike-IgG antibody levels, Nucleocapsid-protein-IgG-antibodies, and vaccine tolerability were assessed 6 weeks after second SARS-CoV-2 vaccination in 137 hemodialysis patients and 24 immunocompetent medical personnel. Results In COVID-19-naïve hemodialysis patients, significantly higher median SARS-CoV-2-spike IgG levels were found after ChAd/BNT (N = 16) compared to BNT/BNT (N = 100) or ChAd/ChAd (N = 10) (1744 [25th–75th percentile 276–2840] BAU/mL versus 361 [25th–75th percentile 120–936] BAU/mL; p = 0.009; 1744 [25th–75th percentile 276–2840] BAU/mL versus 100 [25th–75th percentile 41–346] BAU/mL; p = 0.017, respectively). Vaccinated, COVID-19-naïve medical personnel had median SARS-CoV-2 spike-IgG levels of 650 (25th–75th percentile 217–1402) BAU/mL and vaccinated hemodialysis patients with prior COVID-19 7047 (25th–75th percentile 685–10,794) BAU/mL (N = 11). In multivariable regression analysis, heterologous vaccination (ChAd/BNT) of COVID-19-naïve hemodialysis patients was independently associated with SARS-CoV-2 spike-IgG levels. The first dose of ChAd and the second dose of BNT after the first vaccination with ChAd (heterologous vaccination, ChAd/BNT) were associated with more frequent but manageable side effects compared with homologous BNT. Conclusions Within the limitations of this study, heterologous vaccination with ChAd/BNT appears to induce stronger humoral immunity and more frequent but manageable side effects than homologous vaccination with BNT/BNT or with ChAd/ChAd in COVID-19-naïve hemodialysis patients. Graphical abstract

Background In peritoneal dialysis (PD) patients, information on the immunogenicity and tolerability of SARS‐CoV‐2 vaccination is still scarce. We compared the immunogenicity and tolerability of SARS‐CoV‐2 vaccination of PD patients with that of medical personnel. Methods In a prospective observational cohort study, PD patients and immunocompetent medical personnel were evaluated for SARS‐CoV‐2 spike‐IgG‐ and Nucleocapsid‐IgG‐antibody‐levels before, 2 weeks after the first, and 6 weeks after the second SARS‐CoV‐2 vaccination and vaccine tolerability after the first and second vaccination. Results In COVID‐19‐naïve PD patients (N = 19), lower SARS‐CoV‐2‐spike‐IgG‐levels were found compared with COVID‐19‐naïve medical personnel (N = 24) 6 weeks after second vaccination (median 1438 AU/ml [25th–75th percentile 775–5261] versus 4577 [1529–9871]; p = 0.045). This finding resulted in a lower rate of strong vaccine response (spike‐IgG ≥ 1000 AU/ml) of COVID‐19‐naïve PD patients compared with medical personnel (58% versus 92%; p = 0.013), but not for seroconversion rate (spike‐IgG ≥ 50 AU/ml: 100% vs. 100%; p > 0.99). After first vaccination, COVID‐naïve PD patients presented with significantly fewer side effects than medical personnel (number of any side effect: 1 [1–2] vs. 4 [1–7]; p = 0.015). A similar pattern with slightly decreased frequencies of side effects was observed for tolerability of second SARS‐CoV‐2 vaccination in PD patients and medical personnel (number of any side effects: 1 [1–1] vs. 2 [1–5]; p = 0.006). Conclusions SARS‐CoV‐2 vaccination in COVID‐19‐naïve PD patients appeared to induce a very high rate of seroconversion but a substantially lower rate of patients with a strong response compared with medical personnel. Vaccination appeared to be safe in the PD patients studied.