BackgroundHemodialysis patients are at high risk for severe COVID-19. SARS-CoV-2 vaccination related safety and immunogenicity data in these patients are rare.MethodsIn this observational study SARS-CoV-2-seronegative hemodialysis patients were vaccinated with two doses of the Pfizer/BioNTech mRNA-BNT162b2 vaccine (COMIRNATY® 30 µg) and followed for 90 days. Local and systemic side effects were assessed at every dialysis session during the first post-vaccination week after the first and second vaccine dose. Immunogenicity was determined four weeks after vaccination by quantifying anti-SARS-CoV-2 spike protein IgG antibodies (LIAISON® SARS-CoV-2-TrimericS IgG chemiluminescent immunoassay) expressed in binding activity units per milliliter (BAU/mL) adapted to the WHO International standard.ResultsFifty patients (32% women, 68% men) with a mean (SD) age of 67.6 (14.8) years were included. Mild local reactions occurred in 38% after the first injection, and in 29.2% with mild, in 2.1% with moderate and in 2.1% with severe degree after the second injection. Systemic reactive events occurred less often, with diarrhea (4% mild, 4% moderate) and fatigue (8% mild) being the most frequent ones. After the first injection 42% of the patients developed a positive response using the assay specific cut-off value of 33.8 binding activity units per milliliter (BAU/mL) with a median (Q1, Q3) anti-SARS-CoV-2 spike IgG concentration of 20.0 (11.7, 51.0) BAU/mL. After the second injection the percentage of seropositive patients increased to 97.9% with an anti-SARS-CoV-2 spike IgG concentration of 1075 (290.8, 1735) BAU/mL. Higher age and immunosuppression were associated with lower, calcitriol treatment and prior seroconversion to hepatitis B vaccination with significantly higher antibody concentration.ConclusionsThe mRNA-BNT162b2 SARS-CoV-2 vaccine appears to be safe and well-tolerated and shows a high immunogenicity in hemodialysis patients.

Summary Haemato‐oncological patients are at risk in case of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection. Currently, vaccination is the best‐evaluated preventive strategy. In the present study, we aimed to assess serological response, predictive markers, and safety of BNT162b2 in haemato‐oncological patients. A total of 259 haemato‐oncological patients were vaccinated with two 30 µg doses of BNT162b2 administered 21 days apart. Serological response was assessed by ELECSYS® Anti‐SARS‐CoV‐2‐S immunoassay before vaccination, and at 3 and 7 weeks after the first dose (T1, T2). Safety assessment was performed. At T2 spike protein receptor binding domain (S/RBD) antibodies were detected in 71·4% of haematological and in 94·5% of oncological patients (P < 0·001). Haematological patients receiving systemic treatment had a 14·2‐fold increased risk of non‐responding (95% confidence interval 3·2–63·3, P = 0·001). Subgroups of patients with lymphoma or chronic lymphocytic leukaemia were at highest risk of serological non‐response. Low immunoglobulin G (IgG) level, lymphocyte‐ and natural killer (NK)‐cell counts were significantly associated with poor serological response (P < 0·05). Vaccination was well tolerated with only 2·7% of patients reporting severe side‐effects. Patients with side‐effects developed a higher S/RBD‐antibody titre compared to patients without side‐effects (P = 0·038). Haematological patients under treatment were at highest risk of serological non‐response. Low lymphocytes, NK cells and IgG levels were found to be associated with serological non‐response. Serological response in oncological patients was encouraging. The use of BNT162b2 is safe in haemato‐oncological patients.

Summary Patients with haemato‐oncological malignancies are one of the high‐risk groups for a severe course in case of COVID‐19 infections. Furthermore, vaccination results in significantly lower response rates in haematological malignancies and lower antibody levels in patients with solid cancer. We investigated efficacy and safety of a heterologous booster vaccination with Ad26.COV2.S DNA vector vaccine in haemato‐oncological patients without antibody response after double‐dose BNT162b2 messenger (m‐)RNA COVID‐19 vaccine. A total of 32 haemato‐oncological non‐responders to double‐dose BNT162b2 received a heterologous booster vaccination with Ad26.COV2.S. Blood samples were assessed directly before the vaccination (T0) and four weeks after (T1). Safety assessment was performed using a standardised questionnaire. The overall response rate was 31%, with a mean (SD) antibody titre of 693·79 (1 096·99) binding activity units (BAU)/ml. Patients with chronic lymphocytic leukaemia or lymphoma showed a significantly lower response rate (P = 0·048). Adverse events were reported in 29·6% of patients, of which 7·1% were graded as severe, including grade III and IV events following the Common Terminology Criteria of Adverse Events (CTCAE). The heterologous booster vaccination with Ad26.COV2.S led to a serological response in nine out of 29 patients without response after double‐dose BNT162b2. Furthermore, the vaccination was safe in our cohort, leading to mainly mild local and systemic reactions. Overall, this vaccination regimen should be further evaluated to increase the response rate in the highly vulnerable population of haemato‐oncological patients.