Safety and Immunogenicity of the BNT162b2 mRNA COVID-19 Vaccine in Patients after Allogeneic HCT or CD19-based CART therapy-A Single-Center Prospective Cohort Study

SARS-CoV-2 Vaccination in the First Year After Hematopoietic Cell Transplant or Chimeric Antigen Receptor T-Cell Therapy: A Prospective, Multicenter, Observational Study

BACKGROUND

The optimal timing of vaccination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines after cellular therapy is incompletely understood. The objectives of this study are to determine whether humoral and cellular responses after SARS-CoV-2 vaccination differ if initiated <4 months versus 4-12 months after cellular therapy.

METHODS

We conducted a multicenter, prospective, observational study at 30 cancer centers in the United States. SARS-CoV-2 vaccination was administered as part of routine care. We obtained blood prior to and after vaccinations at up to 5 time points and tested for SARS-CoV-2 spike (anti-S) IgG in all participants and neutralizing antibodies for Wuhan D614G, Delta B.1.617.2, and Omicron B.1.1.529 strains, as well as SARS-CoV-2-specific T-cell receptors, in a subgroup.

RESULTS

We enrolled 466 allogeneic hematopoietic cell transplantation (HCT) (n = 231), autologous HCT (n = 170), and chimeric antigen receptor T-cell (CAR-T-cell) therapy (n = 65) recipients between April 2021 and June 2022. Humoral and cellular responses did not significantly differ among participants initiating vaccinations <4 months versus 4-12 months after cellular therapy. Anti-S IgG ≥2500 U/mL was correlated with high neutralizing antibody titers and attained by the last time point in 70%, 69%, and 34% of allogeneic HCT, autologous HCT, and CAR-T-cell recipients, respectively. SARS-CoV-2-specific T-cell responses were attained in 57%, 83%, and 58%, respectively. Pre-cellular therapy SARS-CoV-2 infection or vaccination and baseline B-cell count were key predictors of post-cellular therapy immunity.

CONCLUSIONS

These data support mRNA SARS-CoV-2 vaccination prior to, and reinitiation 3 to 4 months after, cellular therapies with allogeneic HCT, autologous HCT, and CAR-T-cell therapy.

Cellular and humoral immunogenicity against SARS-CoV-2 vaccination or infection is associated with the memory phenotype of T- and B-lymphocytes in adult allogeneic hematopoietic cell transplant recipients

We conducted a cross-sectional study to evaluate cellular and humoral immunogenicity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination or infection and examine how lymphocyte subpopulations in peripheral blood correlate with cellular and humoral immunogenicity in adult allogeneic hematopoietic cell transplantation (HCT) recipients. The median period from SARS-CoV-2 vaccination or infection to sample collection was 110.5 days (range, 6-345 days). The median SARS-CoV-2 spike-specific antibody level was 1761 binding antibody units (BAU)/ml (range, 0 to > 11,360 BAU/ml). Enzyme-linked immunosorbent spot (ELISpot) assay of T cells stimulated with SARS-CoV-2 spike antigens showed that interferon-gamma (IFN-γ)-, interleukin-2 (IL-2)-, and IFN-γ + IL-2-producing T cells were present in 68.9%, 62.0%, and 56.8% of patients, respectively. The antibody level was significantly correlated with frequency of IL-2-producing T cells (P = 0.001) and IFN-γ + IL-2-producing T cells (P = 0.006) but not IFN-γ-producing T cells (P = 0.970). Absolute counts of CD8+ and CD4+ central memory T cells were higher in both IL-2- and IFN-γ + IL-2-producing cellular responders compared with non-responders. These data suggest that cellular and humoral immunogenicity against SARS-CoV-2 vaccination or infection is associated with the memory phenotype of T cells and B cells in adult allogeneic HCT recipients.

Immunologic Predictors of Vaccine Responsiveness in Patients With Lymphoma and Chronic Lymphocytic Leukemia

Patients with B-cell lymphomas have altered cellular components of vaccine responses due to malignancy and therapy, and the optimal timing of vaccination relative to therapy remains unknown. Severe acute respiratory syndrome coronavirus 2 vaccines created an opportunity for new insights in vaccine timing because patients were challenged with a novel antigen across multiple phases of treatment. We studied serologic messenger RNA vaccine response in retrospective and prospective cohorts with lymphoma and chronic lymphocytic leukemia, paired with clinical and research immune parameters. Reduced serologic response was observed more frequently during active treatment, but nonresponse was also common within observation and posttreatment groups. Total immunoglobulin A and immunoglobulin M correlated with successful vaccine response. In individuals treated with anti-CD19-directed chimeric antigen receptor-modified T cells, nonresponse was associated with reduced B and T follicular helper cells. Predictors of vaccine response varied by disease and therapeutic group, and therefore further studies of immune health during and after cancer therapies are needed to individualize vaccine timing.

Infections associated with CAR-T cell therapy in patients with relapsed refractory multiple myeloma: Risks and prevention strategies

BACKGROUND

Chimeric antigen receptor T (CAR-T) cell therapy has emerged as a potent treatment for relapsed or refractory multiple myeloma, demonstrating significant clinical efficacy. Despite these advances, treatment-related toxicities, particularly infections, pose a significant challenge to patient safety.

METHODS

This review synthesizes current knowledge on the mechanisms underlying post-CAR-T therapy infections, focusing on the interplay between immune dysfunction, host factors, and treatment-induced toxicity. It provides a comprehensive analysis of the temporal and individual variability in infection characteristics and the confounding clinical presentation of cytokine release syndrome.

RESULTS

The review identifies that patients receiving CAR-T cells are at increased risk of concurrent infections due to the heterogeneity in infection characteristics across different time periods, individuals, and patient groups. It highlights the diagnostic and therapeutic complexities introduced by the overlapping symptoms of infection and cytokine release syndrome.

CONCLUSION

To enhance the infection control post-CAR-T therapy, this review proposes preventive strategies tailored to the early and long-term management of patients. It underscores the need for a nuanced understanding of infection mechanisms and the importance of personalized prevention plans to improve clinical outcomes in multiple myeloma treatment.

Vaccination of Adults With Cancer: ASCO Guideline

PURPOSE

To guide the vaccination of adults with solid tumors or hematologic malignancies.

METHODS

A systematic literature review identified systematic reviews, randomized controlled trials (RCTs), and nonrandomized studies on the efficacy and safety of vaccines used by adults with cancer or their household contacts. This review builds on a 2013 guideline by the Infectious Disease Society of America. PubMed and the Cochrane Library were searched from January 1, 2013, to February 16, 2023. ASCO convened an Expert Panel to review the evidence and formulate recommendations.

RESULTS

A total of 102 publications were included in the systematic review: 24 systematic reviews, 14 RCTs, and 64 nonrandomized studies. The largest body of evidence addressed COVID-19 vaccines.

RECOMMENDATIONS

The goal of vaccination is to limit the severity of infection and prevent infection where feasible. Optimizing vaccination status should be considered a key element in the care of patients with cancer. This approach includes the documentation of vaccination status at the time of the first patient visit; timely provision of recommended vaccines; and appropriate revaccination after hematopoietic stem-cell transplantation, chimeric antigen receptor T-cell therapy, or B-cell-depleting therapy. Active interaction and coordination among healthcare providers, including primary care practitioners, pharmacists, and nursing team members, are needed. Vaccination of household contacts will enhance protection for patients with cancer. Some vaccination and revaccination plans for patients with cancer may be affected by the underlying immune status and the anticancer therapy received. As a result, vaccine strategies may differ from the vaccine recommendations for the general healthy adult population vaccine.Additional information is available at www.asco.org/supportive-care-guidelines.

Immunologic responses to the third and fourth doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in cell therapy recipients: a systematic review and meta-analysis

BACKGROUND

Multiple studies have provided evidence of suboptimal or poor immune responses to SARS-CoV-2 vaccines in recipients of hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor-T (CAR-T) cell therapy compared to healthy individuals. Given the dynamic nature of SARS-CoV2, characterized by the emergence of many viral variations throughout the general population, there is ongoing discussion regarding the optimal quantity and frequency of additional doses required to sustain protection against SARS-CoV2 especially in this susceptible population. This systematic review and meta-analysis investigated the immune responses of HSCT and CAR-T cell therapy recipients to additional doses of the SARS-CoV-2 vaccines.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the study involved a comprehensive search across PubMed, Scopus, Web of Science Core Collection, Embase, and Cochrane Biorxiv and medRxiv, focusing on the serological responses to the third and fourth vaccine doses in HSCT and CAR-T cell patients.

RESULTS

This study included 32 papers, with 31 qualifying for the meta-analysis. Results showed that after the third dose, the seroconversion rate in HSCT and CAR-T cell therapy recipients who didn't respond to the second dose was 46.10 and 17.26%, respectively. Following the fourth dose, HSCT patients had a seroconversion rate of 27.23%. Moreover, post-third-dose seropositivity rates were 87.14% for HSCT and 32.96% for CAR-T cell therapy recipients. Additionally, the seropositive response to the fourth dose in the HSCT group was 90.04%.

CONCLUSION

While a significant portion of HSCT recipients developed antibodies after additional vaccinations, only a minority of CAR-T cell therapy patients showed a similar response. This suggests that alternative vaccination strategies are needed to protect these vulnerable groups effectively. Moreover, few studies have reported cellular responses to additional SARS-CoV-2 vaccinations in these patients. Further studies evaluating cellular responses are required to determine a more precise assessment of immunogenicity strength against SARS-CoV-2 after additional doses.

Monitoring Humoral Response Following BNT162b2 mRNA Vaccination against SARS-CoV-2 in Hematopoietic Stem-Cell Transplantation Patients: A Single-Center Prospective Study along with a Brief Review of Current Literature

Data on antibody response (AR) after vaccination against SARS-CoV2 in hematopoietic stem-cell transplantation setting (HSCT) were initially scarce, mainly due to the exclusion of such patients from approval studies. Shortly after the worldwide application of vaccination against SARS-CoV-2 in vulnerable populations such as patients with hematologic malignancies, limited single-center trials, including HSCT patients, were published. However, there was a great heterogeneity between them regarding the type of underlying malignancy, co-current treatment, type of vaccine, method of AR measurement, and time point of AR measurement. Herein, we present the results of a prospective study on AR after vaccination for SARS-CoV-2 using the BNT162b2 vaccine in a cohort of 54 HSCT recipients-mostly autologous from a single Unit-along with a broad review of the current literature. In our cohort, the AR positivity rate at 1 month was 80.8% and remained positive in 85.7% of patients at 3 months after vaccination. There were only nine non-responders, who were more heavily pretreated and more frequently hypogammaglobulinemic compared to responders. High antibody titers (AT), [AT ≥ 1000 U/mL], were detected in 38.5% and 30.6% of the patients at m1 and m3, respectively. A significant decline in AT between m1 and m3 was demonstrated-p < 0.0001; median AT1 and AT3 were 480.5 and 293 U/mL, respectively. A novel finding of our study was the negative impact of IgA hypogammaglobulinemia on response to vaccination. Other negative significant factors were treatment with anti-CD20 antibody at vaccination and vaccination within 18 months from HSCT. Our data indicate that HSCT recipients elicit a positive response to the BNT162b2 vaccine against SARS-CoV-2 when vaccinated at 6 months post-transplant, and vaccination should be offered to this patient population even within the post-pandemic COVID-19 era.

Serial Evaluation of Preimmunization Antibody Titers in Lymphoma Patients Receiving Chimeric Antigen Receptor T Cell Therapy

Antibody titers and the potential need for immunization have not been formally studied in recipients of chimeric antigen receptor T cell therapy (CAR-T). Prior studies have shown that CD19-targeted CAR-T can induce persistent B cell aplasia but preserve plasma cells for humoral response. Aiming to assess the immune repertoire and antibody titer status of CAR-T recipients, we conducted a retrospective study of immune cell recovery and antibody titers to vaccines in anti-CD19 CAR-T recipients at Mayo Clinic, Rochester. In our cohort of 95 CAR-T recipients, almost one-half had low CD4 T and B cell counts prior to CAR-T that remained persistently low post-CAR-T. Prior to CAR-T, the seronegative rate was lowest for tetanus and highest for pneumococcus irrespective of prior transplantation status (within 2 years of CAR-T). At 3 months post-CAR-T, overall seronegativity rates were similar to pre-CAR-T rates for the prior transplantation and no prior transplantation groups. For patients who received IVIG, loss of seropositivity was seen for hepatitis A (1 of 7; 14%). No seroconversion was noted for pneumococcus. For patients who did not receive IVIG, loss of seropositivity was seen for pneumococcus (2 of 5; 40%) and hepatitis A (1 of 4; 25%). CAR-T recipients commonly experience T cell and B cell lymphopenia and might not have adequate antibody titers against vaccine-preventable diseases despite IVIG supplementation. Loss of antibody titers post-CAR-T is possible, highlighting the need for revaccination. Additional studies with long-term follow-up are needed to inform the optimal timing of immunization post-CAR-T.

Efficacy of Multiple SARS-CoV-2 Vaccine Doses in Patients with B Cell Hematologic Malignancies Receiving Chimeric Antigen Receptor T Cell Therapy: A Contemporary Cohort Analysis

The mortality due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) approaches 40% in recipients of chimeric antigen receptor (CAR) T cell therapy (CAR-T). The efficacy of repeated vaccine doses, including bivalent boosters, remains unknown. We examined the efficacy of repeated vaccine doses among CAR-T recipients who received at least 2 or more vaccine doses after T cell infusion. This single-center retrospective study included adults age >18 years receiving CAR-T for relapsed/refractory (R/R) B cell hematologic malignancies targeting CD19, BCMA, or CD19 and CD20 between September 2018 through March 2022 and were alive beyond 2021 to receive incremental SARS-CoV-2 vaccine doses with available seroconversion data. Multivariable analyses were performed using the design-adjusted Cox regression and logistic regression approaches with stratification. In multivariable analysis, seroconversion rates were significantly greater with a total of 4 or more vaccine doses (odds ratio [OR], 8.22; P = .008). CAR-T recipients with other B cell hematologic malignancies had significantly lower seroconversion rates and diminished Ab titers compared to those with R/R multiple myeloma (OR, .07; P = .003). One patient died due to COVID-19 in this vaccinated study cohort, accounting for a COVID-19-attributable mortality rate of 1.7%. The results provide baseline vaccine response data in a contemporary cohort including patients with diverse group of SARS-COV2 variants and support the latest Centers for Disease Control and Prevention guidelines for repeated vaccinations directed against the prevalent variant of concern.

Immunogenicity and Tolerance of BNT162b2 mRNA Vaccine in Allogeneic Hematopoietic Stem Cell Transplant Patients

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (ASCT) induces acquired immunodeficiency, potentially altering vaccine response. Herein, we aimed to explore the clinical tolerance and the humoral and cellular immune responses following anti-SARS-CoV-2 vaccination in ASCT recipients.

METHODS

A prospective, non-randomized, controlled study that involved 43 ASCT subjects and 31 healthy controls. Humoral response was investigated using the Elecsys® test anti-SARS-CoV-2. Cellular response was assessed using the QFN® SARS-CoV-2 test. The lymphocyte cytokine profile was tested using the LEGENDplex™ HU Th Cytokine Panel Kit (12-plex).

RESULTS

Adverse effects (AE) were observed in 69% of patients, encompassing pain at the injection site, fever, asthenia, or headaches. Controls presented more side effects like pain in the injection site and asthenia with no difference in the overall AE frequency. Both groups exhibited robust humoral and cellular responses. Only the vaccine transplant delay impacted the humoral response alongside a previous SARS-CoV-2 infection. Noteworthily, controls displayed a Th1 cytokine profile, while patients showed a mixed Th1/Th2 profile.

CONCLUSIONS

Pfizer-BioNTech® anti-SARS-CoV-2 vaccination is well tolerated in ASCT patients, inducing robust humoral and cellular responses. Further exploration is warranted to understand the impact of a mixed cytokine profile in ASCT patients.

SARS-CoV-2 vaccination in the first year after hematopoietic cell transplant or chimeric antigen receptor T cell therapy: A prospective, multicenter, observational study (BMT CTN 2101)

Background

The optimal timing of vaccination with SARS-CoV-2 vaccines after cellular therapy is incompletely understood.

Objective

To describe humoral and cellular responses after SARS-CoV-2 vaccination initiated <4 months versus 4-12 months after cellular therapy.

Design

Multicenter prospective observational study.

Setting

34 centers in the United States.

Participants

466 allogeneic hematopoietic cell transplant (HCT; n=231), autologous HCT (n=170), or chimeric antigen receptor T cell (CAR-T cell) therapy (n=65) recipients enrolled between April 2021 and June 2022.

Interventions

SARS-CoV-2 vaccination as part of routine care.

Measurements

We obtained blood prior to and after vaccinations at up to five time points and tested for SARS-CoV-2 spike (anti-S) IgG in all participants and neutralizing antibodies for Wuhan D614G, Delta B.1.617.2, and Omicron B.1.1.529 strains, as well as SARS-CoV-2-specific T cell receptors (TCRs), in a subgroup.

Results

Anti-S IgG and neutralizing antibody responses increased with vaccination in HCT recipients irrespective of vaccine initiation timing but were unchanged in CAR-T cell recipients initiating vaccines within 4 months. Anti-S IgG ≥2,500 U/mL was correlated with high neutralizing antibody titers and attained by the last time point in 70%, 69%, and 34% of allogeneic HCT, autologous HCT, and CAR-T cell recipients, respectively. SARS-CoV-2-specific T cell responses were attained in 57%, 83%, and 58%, respectively. Humoral and cellular responses did not significantly differ among participants initiating vaccinations <4 months vs 4-12 months after cellular therapy. Pre-cellular therapy SARS-CoV-2 infection or vaccination were key predictors of post-cellular therapy anti-S IgG levels.

Limitations

The majority of participants were adults and received mRNA vaccines.

Conclusions

These data support starting mRNA SARS-CoV-2 vaccination three to four months after allogeneic HCT, autologous HCT, and CAR-T cell therapy.

Funding

National Marrow Donor Program, Leukemia and Lymphoma Society, Multiple Myeloma Research Foundation, Novartis, LabCorp, American Society for Transplantation and Cellular Therapy, Adaptive Biotechnologies, and the National Institutes of Health.

COVID‑19 antibody production by vaccination in chemotherapy with CD20 antibody for B‑cell lymphoma

Most hematologic diseases are immunosuppressed, either by the disease itself or by treatment. As such, the implementation of vaccination is largely at the discretion of the attending physician. In this context, an objective measure is needed, therefore the index of vaccination against coronavirus disease 2019 (COVID-19) in B-cell lymphomas treated with antibody therapy against CD20 (including after the completion of therapy) was examined. A total of 40 patients with B-cell lymphoma during or after antibody therapy against CD20 were vaccinated twice with the BNT162b2 messenger RNA (mRNA) COVID-19 vaccine (Pfizer, Inc. and BioNTech SE.) at 3-week intervals and then again six months later with the same vaccine or mRNA-1273 (Moderna, Inc.). Antibody testing was conducted ~1 month after the third vaccination. Analysis was performed using the antibody titers to the anti-spike immunoglobulin assay, with a titer of 0.8 U/ml or higher (considered positive) and a titer of 264 U/ml or higher (considered the value at which the efficacy of the vaccine can be fully expected). Significant factors of antibody acquisition were identified when i) antibody titers were 0.8 U/ml or higher (CD4 ≥400/µl), ii) no anti-CD20 antibody maintenance therapy was undertaken (CD19 ≥100/µl), iii) patients were not on treatment (CD4 ≥400/µl), or 4) at least six months had passed since treatment ended (CD19 ≥100/µl). When antibody titers were 264 U/ml or higher, the treatment method, the stage of the primary disease and other factors related to the condition treatment method of the patient were relevant. When these were analyzed by multivariate analysis, the significant factor when antibody titers were set to 0.8 U/ml was CD19 ≥100/µl. In contrast, when setting them to 264 U/ml or higher, CD4 ≥400/µl was not significant, but there was a tendency for it to be related. The findings of the present study on vaccine-induced antibody acquisition in patients with B-cell lymphoma indicated that it is desirable to have a CD19 titer of at least 100/µl and a CD4 titer of at least 400/µl (both conditions should be met), and that no maintenance therapy with anti-CD20 antibody should be administered for at least six months after the last treatment or completion of the treatment. Interestingly, when the criteria for antibody titers were compared between 0.8 U/ml, where antibody titer is detected, and 264 U/ml, where vaccine efficacy is expected, several key factors were different. It is possible that these key factors may change depending on the antibody titer used as a criterion.

COVID-19 after hematopoietic cell transplantation and chimeric antigen receptor (CAR)-T-cell therapy

More than 3 years have passed since Coronavirus disease 2019 (COVID-19) was declared a global pandemic, yet COVID-19 still severely impacts immunocompromised individuals including those treated with hematopoietic cell transplantation (HCT) and chimeric antigen receptor-T-cell therapies who remain at high risk for severe COVID-19 and mortality. Despite vaccination efforts, these patients have inadequate responses due to immunosuppression, which underscores the need for additional preventive approaches. The optimal timing, schedule of vaccination, and immunological correlates for protective immunity remain unknown. Antiviral therapies used early during disease can reduce mortality and severity due to COVID-19. The combination or sequential use of antivirals could be beneficial to control replication and prevent the development of treatment-related mutations in protracted COVID-19. Despite conflicting data, COVID-19 convalescent plasma remains an option in immunocompromised patients with mild-to-moderate disease to prevent progression. Protracted COVID-19 has been increasingly recognized among these patients and has been implicated in intra-host emergence of SARS-CoV-2 variants. Finally, novel SARS-CoV2-specific T-cells and natural killer cell-boosting (or -containing) products may be active against multiple variants and are promising therapies in immunocompromised patients.

[Characteristics and impact factors of SARS-CoV-2 infection in adult patients with relapsed/refractory B-cell non-Hodgkin lymphoma receiving chimeric antigen receptor T-cell therapy]

Objective: To explore the clinical characteristics and treatment of COVID-19 infection in patients with relapsed/refractory B-cell non-Hodgkin lymphoma before and after receiving chimeric antigen receptor T-cell therapy, and study the influencing factors of severe COVID-19 infection in these patients. Methods: The data of 59 patients with relapsed/refractory B-cell non-Hodgkin lymphoma who received chimeric antigen receptor T-cell therapy at the Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology and Department of Hematology, the Second Affiliated Hospital, College of Medicine, Zhejiang University between December 2017 and February 2023, and who were infected with novel coronavirus between December 2022 and February 2023 were retrospectively studied. Patients were divided into light, medium, severe, and critical groups, and the differences between the groups were analyzed using the chi-square test. A univariate logistic regression model was used to evaluate the contribution of each variable and its relationship with severe infection. The chi-square and Fisher's exact tests were used to analyze the differences between the B-cell aplasia and B-cell recovery (BCR) groups. Results: Of the 59 pre- and post-infusion infections, 39 (66.1%) led to mild COVID-19, 9 (15.3%) resulted in moderate COVID-19, 10 (16.9%) resulted in severe COVID-19, and 1 (1.7%) led to critical COVID-19. Moroever, age greater than 55 years, having received autologous hematopoietic stem cell transplantation, progressive disease status, and B-cell aplasia at the time of diagnosis of COVID-19 infection are factors affecting severe infection. Patients with B-cell aplasia had a more severe infection with COVID-19 (P<0.001), a longer duration (P=0.015), a longer antiviral therapy course (P<0.001), and a higher hospitalization rate (P<0.001) than the BCR group. Conclusion: Active prevention and treatment of COVID-19 infection remains a crucial issue requiring urgent attention in managing patients with relapsed/refractory B-cell non-Hodgkin lymphoma treated with chimeric antigen receptor T-cell therapy.

Attenuated immunogenicity of SARS-CoV-2 vaccines and risk factors in stem cell transplant recipients: a meta-analysis

Immunogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is diminished in hematopoietic stem cell transplant (HSCT) recipients. To summarize current evidence and identify risk factors for attenuated responses, 5 electronic databases were searched since database inceptions through 12 January 2023 for studies reporting humoral and/or cellular immunogenicity of SARS-CoV-2 vaccination in the HSCT population. Using descriptive statistics and random-effects models, extracted numbers of responders and pooled odds ratios (pORs) with 95% confidence intervals (CIs) for risk factors of negative immune responses were analyzed (PROSPERO: CRD42021277109). From 61 studies with 5906 HSCT recipients, after 1, 2, and 3 doses of messenger RNA (mRNA) SARS-CoV-2 vaccines, the mean antispike antibody seropositivity rates (95% CI) were 38% (19-62), 81% (77-84), and 80% (75-84); neutralizing antibody seropositivity rates were 52% (40-64), 71% (54-83), and 78% (61-89); and cellular immune response rates were 52% (39-64), 66% (51-79), and 72% (52-86). After 2 vaccine doses, risk factors (pOR; 95% CI) associated with antispike seronegativity were male recipients (0.63; 0.49-0.83), recent rituximab exposure (0.09; 0.03-0.21), haploidentical allografts (0.46; 0.22-0.95), <24 months from HSCT (0.25; 0.07-0.89), lymphopenia (0.18; 0.13-0.24), hypogammaglobulinemia (0.23; 0.10-0.55), concomitant chemotherapy (0.48; 0.29-0.78) and immunosuppression (0.18; 0.13-0.25). Complete remission of underlying hematologic malignancy (2.55; 1.05-6.17) and myeloablative conditioning (1.72; 1.30-2.28) compared with reduced-intensity conditioning were associated with antispike seropositivity. Ongoing immunosuppression (0.31; 0.10-0.99) was associated with poor cellular immunogenicity. In conclusion, attenuated humoral and cellular immune responses to mRNA SARS-CoV-2 vaccination are associated with several risk factors among HSCT recipients. Optimizing individualized vaccination and developing alternative COVID-19 prevention strategies are warranted.

Association of Self-Reported COVID-19 Vaccination Status with COVID-19 Infection among Adult Long-Term Hematopoietic Cell Transplantation Survivors

Hematopoietic cell transplantation (HCT) recipients experience significant morbidity and mortality from coronavirus disease 19 (COVID-19) infection. Data are limited regarding long-term HCT survivors' uptake of and experiences with COVID-19 vaccination and infection. This study aimed to characterize COVID-19 vaccination uptake, use of other prevention measures, and COVID-19 infection outcomes in adult HCT recipients at our institution. Between July 1, 2021, and June 30, 2022, long-term adult HCT survivors were surveyed regarding overall health, chronic graft-versus-host (cGVHD) status, and experiences with COVID-19 vaccinations, prevention measures, and infections. Patients reported COVID-19 vaccination status, vaccine-related adverse effects, use of nonpharmaceutical prevention measures, and infections. Comparisons by response and vaccination status were performed using the chi-square test and Fisher exact test for categorical variables and the Kruskal-Wallis test for continuous variables. Of 4758 adult HCT survivors who underwent HCT between 1971 and 2021 and consented to participate in annual surveys, 1719 (36%) completed the COVID-19 module, and 1598 of 1705 (94%) reported receiving ≥1 dose of COVID-19 vaccine. Severe vaccine-related adverse effects were infrequent (5%). Among respondents receiving an mRNA vaccine, completion of doses according to the Centers for Disease Control and Prevention's vaccine recommendations at the time of survey return was 2 doses in 675 of 759 (89%), 3 doses in 610 of 778 (78%), and 4 doses in 26 of 55 (47%). Two hundred fifty respondents (15%) reported COVID-19 infection; 25 (10%) required hospitalization. Vaccinated respondents reported significantly higher uptake of household vaccination (1284 of 1404 [91%] versus 18 of 88 [20%]; P < .001) and the use of nonpharmaceutical interventions (P < .001). Vaccinated respondents were significantly less likely to have contracted COVID-19 (85 of 1480 [6%] versus 130 of 190 [68%]; P < .001), as were their household members (149 of 1451 [10%] versus 85 of 185 [46%]; P < .001). Receipt of additional COVID-19 vaccine doses beyond the first dose was associated with a reduced risk of COVID-19 infection (odds ratio, .63; 95% confidence interval, .47 to .85; P = .002). Vaccination was well tolerated and associated with a lower risk of COVID-19 infection among HCT survivors and their household contacts. Vaccination and booster doses should be encouraged as part of a multifaceted approach in this high-risk population.

Acute exacerbation of ocular graft-versus-host disease and anterior uveitis after COVID-19 vaccination

BACKGROUND

To report a case of simultaneous occurrence of acute exacerbation of ocular graft-versus-host disease (GVHD) and anterior uveitis following coronavirus disease 2019 (COVID-19) vaccination.

CASE PRESENTATION

A 60-year-old man with primary myelofibrosis and GVHD after receiving allogeneic hematopoietic stem cell transplantation (HSCT), developed acute exacerbation of ocular GVHD and anterior uveitis after receiving first dose of COVID-19 vaccine. The patient developed erythema of the eyelids, conjunctival hyperemia, superficial punctate keratopathy, and prominent anterior chamber inflammation in both eyes. The ocular GVHD and anterior uveitis were managed with mainly topical corticosteroids, antibiotics, lubricants, and systemic corticosteroids, but were difficult to control. Intravitreal injection of dexamethasone was administered, and the inflammation gradually subsided 6 months after the onset of initial symptoms.

CONCLUSIONS

Clinicians should be aware of rare refractory anterior uveitis and acute exacerbation of ocular GVHD after COVID-19 vaccination in patients undergoing HSCT. Early diagnosis and aggressive treatment should be considered to reduce the likelihood of severe complications.

Multidisciplinary recommendations for the management of CAR-T recipients in the post-COVID-19 pandemic era

The outbreak of coronavirus disease 2019 (COVID-19) posed an unprecedented challenge on public health systems. Despite the measures put in place to contain it, COVID-19 is likely to continue experiencing sporadic outbreaks for some time, and individuals will remain susceptible to recurrent infections. Chimeric antigen receptor (CAR)-T recipients are characterized by durable B-cell aplasia, hypogammaglobulinemia and loss of T-cell diversity, which lead to an increased proportion of severe/critical cases and a high mortality rate after COVID-19 infection. Thus, treatment decisions have become much more complex and require greater caution when considering CAR T-cell immunotherapy. Hence, we reviewed the current understanding of COVID-19 and reported clinical experience in the management of COVID-19 and CAR-T therapy. After a panel discussion, we proposed a rational procedure pertaining to CAR-T recipients with the aim of maximizing the benefit of CAR-T therapy in the post COVID-19 pandemic era.

Vaccinations in hematological patients in the era of target therapies: Lesson learnt from SARS-CoV-2

Novel targeting agents for hematologic diseases often exert on- or off-target immunomodulatory effects, possibly impacting on response to anti-SARS-CoV-2 vaccinations and other vaccines. Agents that primarily affect B cells, particularly anti-CD20 monoclonal antibodies (MoAbs), Bruton tyrosine kinase inhibitors, and anti-CD19 chimeric antigen T-cells, have the strongest impact on seroconversion. JAK2, BCL-2 inhibitors and hypomethylating agents may hamper immunity but show a less prominent effect on humoral response to vaccines. Conversely, vaccine efficacy seems not impaired by anti-myeloma agents such as proteasome inhibitors and immunomodulatory agents, although lower seroconversion rates are observed with anti-CD38 and anti-BCMA MoAbs. Complement inhibitors for complement-mediated hematologic diseases and immunosuppressants used in aplastic anemia do not generally affect seroconversion rate, but the extent of the immune response is reduced under steroids or anti-thymocyte globulin. Vaccination is recommended prior to treatment or as far as possible from anti-CD20 MoAb (at least 6 months). No clearcut indications for interrupting continuous treatment emerged, and booster doses significantly improved seroconversion. Cellular immune response appeared preserved in several settings.

Case report: Sudden onset optic neuritis shortly after SARS-CoV-2 vaccination in an allogeneic hematopoietic stem cell transplant recipient with chronic graft-vs.-host disease

Hematopoietic stem cell transplantation (HSCT) recipients affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have a high mortality rate. The American Society of Transplantation and Cellular Therapy (ASTCT) and the European Society for Blood and Marrow Transplantation (EBMT) recommend vaccination for these vulnerable populations. However, emerging data suggested that vaccination might elicit immunological adverse events, including an exacerbation of graft-vs.-host disease (GVHD). Herein, we report a case of severe optic neuritis developed shortly after AstraZeneca COVID-19 vaccination in an allogeneic HSCT recipient with underlying chronic GVHD. The patient had a headache 5 days after vaccination, and the disease progressed rapidly to complete blindness 17 days after the vaccination. The diagnosis of optic neuritis was well-confirmed by the presence of an anti-myelin oligodendrocyte glycoprotein antibody and the typical features of MRI image and Ophthalmoscopy. Other differential diagnoses, such as infection or leukemia relapse in the central nervous system (CNS), were carefully excluded. A timely high-dose corticosteroid was administered, and her visual acuity improved rapidly. She returned to her baseline status 1 month later. With more than 1 year of follow-up, no optic neuritis or leukemia relapse was observed. In summary, allogeneic transplant recipients can develop severe optic neuritis after vaccination. Optic neuritis can be an exacerbation of GVHD or rarely a sporadic adverse event of vaccination. Furthermore, our experience indicates that a prompt diagnosis and early steroid treatment are vital for a good recovery.

Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine Immunogenicity among Chimeric Antigen Receptor T Cell Therapy Recipients

Patients receiving chimeric antigen receptor T cell (CAR-T) therapy may have impaired humoral responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccinations owing to their underlying hematologic malignancy, prior lines of therapy, and CAR-T-associated hypogammaglobulinemia. Comprehensive data on vaccine immunogenicity in this patient population are limited. A single-center retrospective study of adults receiving CD19 or BCMA-directed CAR-T therapy for B cell non-Hodgkin lymphoma or multiple myeloma was conducted. Patients received at least 2 doses of SARS-CoV-2 vaccination with BNT162b2 or mRNA-1273 or 1 dose of Ad26.COV2.S and had SARS-CoV-2 anti-spike antibody (anti-S IgG) levels measured at least 1 month after the last vaccine dose. Patients were excluded if they received SARS-CoV-2 monoclonal antibody therapy or immunoglobulin within 3 months of the index anti-S titer. The seropositivity rate (assessed by an anti-S assay cutoff of ≥.8 U/mL in the Roche assay) and median anti-S IgG titers were analyzed. Fifty patients were included in the study. The median age was 65 years (interquartile range [IQR], 58 to 70 years), and the majority were male (68%). Thirty-two participants (64%) had a positive antibody response, with a median titer of 138.5 U/mL (IQR, 11.61 to 2541 U/mL). Receipt of ≥3 vaccines was associated with a significantly higher anti-S IgG level. Our study supports current guidelines for SARS-CoV-2 vaccination among recipients of CAR-T therapy and demonstrates that a 3-dose primary series followed by a fourth booster increases antibody levels. However, the relatively low magnitude of titers and low percentage of nonresponders demonstrates that further studies are needed to optimize vaccination timing and determine predictors of vaccine response in this population.

Specific immune response to mRNA vaccines against COVID-19 in patients receiving allogeneic stem cell transplantation for myeloid malignancy was altered by immunosuppressive therapy

BACKGROUND

Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are at high risk of complications associated with COVID-19 infection due to dysfunction of their immune system. Vaccination can protect from the adverse consequences of COVID-19. However, studies on the efficacy of COVID-19 vaccines in HSCT recipients with insufficient post-HSCT immune reconstitution are still scarce. In our study, we determined how immunosuppressive medication and the reconstitution of the cellular immune system influenced T cell responses specific for the surface glycoprotein of SARS-CoV-2 virus (S antigen) after two doses of mRNA vaccine against COVID-19 in patients with myeloid malignancies treated with HSCT.

METHODS

Vaccination outcomes were followed in 18 (allo-HSCT) recipients and 8 healthy volunteers. The IgG antibodies against SARS-CoV-2 spike (S) and nucleocapsid (NCP) protein were determined in ELISA and S-specific T cells were detected using a sensitive ELISPOT-IFNγ based on in vitro expansion and restimulation of T cells in pre- and post-vaccination blood samples. Multiparametric flow cytometry analysis of peripheral blood leukocyte differentiation markers was employed for determination of reconstitution of the main subpopulations of T cells and NK cells at month 6 after HSCT.

RESULTS

S- specific IgG antibody response detected in 72% of the patients was lower than in healthy vaccinees (100%). Vaccine-induced T-cell responses to S1 or S2 antigen were significantly reduced in HSCT recipients, which were treated with corticosteroids in dose 5 mg of prednisone- equivalents or higher during the vaccination period or in preceeding 100 days in comparison with recipients un-affected with corticosteroids. A significant positive correlation was found between the level of anti-SARS-Cov-2 spike protein IgG antibodies and the number of functional S antigen-specific T cells. Further analysis also showed that the specific response to vaccination was significantly influenced by the interval between administration of vaccine and transplantation. Vaccination outcomes were not related to age, sex, type of mRNA vaccine used, basic diagnosis, HLA match between HSC donor and recipient, and blood counts of lymphocytes, neutrophils, and monocytes at the time of vaccination. Multiparametric flow cytometry analysis of peripheral blood leukocyte differentiation markers showed that good humoral and cellular S-specific immune responses induced by vaccination were associated with well-reconstituted CD4⁺ T cells, mainly CD4⁺ effector memory subpopulation at six months after HSCT.

CONCLUSIONS

The results showed that both humoral and cellular adaptive immune responses of HSCT recipients to the SARS-CoV-2 vaccine were significantly suppressed by corticosteroid therapy. Specific response to the vaccine was significantly affected by the length of the interval between HSCT and vaccination. Vaccination as early as 5 months after HSCT can lead to a good response. Immune response to the vaccine is not related to age, gender, HLA match between HSC donor and recipient, or type of myeloid malignancy. Vaccine efficacy was dependent on well-reconstituted CD4⁺ T cells, at six months after HSCT.

SARS-CoV-2 vaccination in the first year after allogeneic hematopoietic cell transplant: a prospective, multicentre, observational study

Background

The optimal timing for SARS-CoV-2 vaccines within the first year after allogeneic hematopoietic cell transplant (HCT) is poorly understood.

Methods

We conducted a prospective, multicentre, observational study of allogeneic HCT recipients who initiated SARS-CoV-2 vaccinations within 12 months of HCT. Participants were enrolled at 22 academic cancer centers across the United States. Participants of any age who were planning to receive a first post-HCT SARS-CoV-2 vaccine within 12 months of HCT were eligible. We obtained blood prior to and after each vaccine dose for up to four vaccine doses, with an end-of-study sample seven to nine months after enrollment. We tested for SARS-CoV-2 spike protein (anti-S) IgG; nucleocapsid protein (anti-N) IgG; neutralizing antibodies for Wuhan D614G, Delta B.1.617.2, and Omicron B.1.1.529 strains; and SARS-CoV-2-specific T-cell receptors (TCRs). The primary outcome was a comparison of anti-S IgG titers at the post-V2 time point in participants initiating vaccinations <4 months versus 4-12 months after HCT using a propensity-adjusted analysis. We also evaluated factors associated with high-level anti-S IgG titers (≥2403 U/mL) in logistic regression models.

Findings

Between April 22, 2021 and November 17, 2021, 175 allogeneic HCT recipients were enrolled in the study, of whom all but one received mRNA SARS-CoV-2 vaccines. SARS-CoV-2 anti-S IgG titers, neutralizing antibody titers, and TCR breadth and depth did not significantly differ at all tested time points following the second vaccination among those initiating vaccinations <4 months versus 4-12 months after HCT. Anti-S IgG ≥2403 U/mL correlated with neutralizing antibody levels similar to those observed in a prior study of non-immunocompromised individuals, and 57% of participants achieved anti-S IgG ≥2403 U/mL at the end-of-study time point. In models adjusted for SARS-CoV-2 infection pre-enrollment, SARS-CoV-2 vaccination pre-HCT, CD19+ B-cell count, CD4+ T-cell count, and age (as applicable to the model), vaccine initiation timing was not associated with high-level anti-S IgG titers at the post-V2, post-V3, or end-of-study time points. Notably, prior graft-versus-host-disease (GVHD) or use of immunosuppressive medications were not associated with high-level anti-S IgG titers. Grade ≥3 vaccine-associated adverse events were infrequent.

Interpretation

These data support starting mRNA SARS-CoV-2 vaccination three months after HCT, irrespective of concurrent GVHD or use of immunosuppressive medications. This is one of the largest prospective analyses of vaccination for any pathogen within the first year after allogeneic HCT and supports current guidelines for SARS-CoV-2 vaccination starting three months post-HCT. Additionally, there are few studies of mRNA vaccine formulations for other pathogens in HCT recipients, and these data provide encouraging proof-of-concept for the utility of early vaccination targeting additional pathogens with mRNA vaccine platforms.

Funding

National Marrow Donor Program, Leukemia and Lymphoma Society, Multiple Myeloma Research Foundation, Novartis, LabCorp, American Society for Transplantation and Cellular Therapy, Adaptive Biotechnologies, and the National Institutes of Health.

Is a third SARS-CoV-2 vaccine dose efficient in allogeneic haematopoietic cell transplant recipients?

When and how often should allogeneic haematopoietic cell transplantation recipients be vaccinated against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is unclear. The report by Bankova et al. suggests that a third SARS-CoV-2 vaccine dose is important but still insufficient in some patients to establish an adequate humoral response. Commentary on: Bankova et al. Antibody response to a third SARS-CoV-2 vaccine dose in recipients of an allogeneic hematopoietic cell transplantation. Br J Haematol. 2023;201:58-63.

Third BNT162b2 mRNA SARS-CoV-2 Vaccine Dose Significantly Enhances Immunogenicity in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

COVID-19-related mortality among hematopoietic stem cell transplantation (HSCT) recipients in the pre-vaccine era ranged between 22 and 33%. The Pfizer/BioNTech BNT162b2 vaccine demonstrated significant immunogenicity and efficacy in the healthy population; however, its long-term effects on allogeneic HSCT recipients remained unclear. Our study longitudinally evaluated humoral and cellular responses to the BNT162b2 vaccine in adult allogeneic HSCT patients. A positive response was defined as antibody titers ≥ 150 AU/mL post-second vaccination. Among 77 included patients, 51 (66.2%) responded to vaccination. Response-associated factors were female gender, recent anti-CD20 therapy, and a longer interval between transplant and vaccination. Response rates reached 83.7% in patients vaccinated >12 months post-transplant. At 6 months post-second vaccination, antibody titers dropped, but were significantly increased with the booster dose. Moreover, 43% (6/14) of non-responders to the second vaccination acquired sufficient antibody titers after booster administration, resulting in an overall response rate of 79.5% for the entire cohort. The BNT162b2 vaccine was effective in allogeneic transplant recipients. Although antibody titers decreased with time, the third vaccination led to their significant elevation, with 93% of third-dose responders maintaining titers above 150 AU/mL at 3 months post-administration.

Functional SARS-CoV-2-specific T cells of donor origin in allogeneic stem cell transplant recipients of a T-cell-replete infusion: A prospective observational study

In the current post-pandemic era, recipients of an allogeneic hematopoietic stem cell transplant (HCT) deserve special attention. In these vulnerable patients, vaccine effectiveness is reduced by post-transplant immune-suppressive therapy; consequently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) is often associated with elevated morbidity and mortality. Characterizing SARS-CoV-2 adaptive immunity transfer from immune donors to HCT recipients in the context of immunosuppression will help identify optimal timing and vaccination strategies that can provide adequate protection to HCT recipients against infection with evolving SARS-CoV-2 variants. We performed a prospective observational study (NCT04666025 at ClinicalTrials.gov) to longitudinally monitor the transfer of SARS-CoV-2-specific antiviral immunity from HCT donors, who were either vaccinated or had a history of COVID-19, to their recipients via T-cell replete graft. Levels, function, and quality of SARS-CoV-2-specific immune responses were longitudinally analyzed up to 6 months post-HCT in 14 matched unrelated donor/recipients and four haploidentical donor/recipient pairs. A markedly skewed donor-derived SARS-CoV-2 CD4 T-cell response was measurable in 15 (83%) recipients. It showed a polarized Th1 functional profile, with the prevalence of central memory phenotype subsets. SARS-CoV-2-specific IFN-γ was detectable throughout the observation period, including early post-transplant (day +30). Functionally experienced SARS-CoV-2 Th1-type T cells promptly expanded in two recipients at the time of post-HCT vaccination and in two others who were infected and survived post-transplant COVID-19 infection. Our data suggest that donor-derived SARS-CoV-2 T-cell responses are functional in immunosuppressed recipients and may play a critical role in post-HCT vaccine response and protection from the fatal disease.

Clinical trial registration

clinicaltrials.gov, identifier NCT04666025.

AGIHO guideline on evidence-based management of COVID-19 in cancer patients: 2022 update on vaccination, pharmacological prophylaxis and therapy in light of the omicron variants

The novel coronavirus SARS-CoV-2 and the associated infectious disease COVID-19 pose a significant challenge to healthcare systems worldwide. Patients with cancer have been identified as a high-risk population for severe infections, rendering prophylaxis and treatment strategies for these patients particularly important. Rapidly evolving clinical research, resulting in the recent advent of various vaccines and therapeutic agents against COVID-19, offers new options to improve care and protection of cancer patients. However, ongoing epidemiological changes and rise of new virus variants require repeated revisions and adaptations of prophylaxis and treatment strategies to meet these new challenges. Therefore, this guideline provides an update on evidence-based recommendations with regard to vaccination, pharmacological prophylaxis and treatment of COVID-19 in cancer patients in light of the currently dominant omicron variants. It was developed by an expert panel of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO) based on a critical review of the most recent available data.

Humoral response and safety of the BNT162b2 and mRNA-1273 COVID-19 vaccines in allogeneic hematopoietic stem cell transplant recipients: An observational study

BACKGROUND

The effectiveness of mRNA COVID-19 vaccines and the optimal timing of vaccine administration in allogeneic hematopoietic stem cell transplantation (Allo-HSCT) recipients remains inadequately investigated. We examine the effectiveness and safety of mRNA COVID-19 vaccines in allo-HSCT recipients.

METHOD

This prospective observational study included 44 allo-HSCT recipients and 38 healthy volunteers. The proportion of subjects acquiring anti-S1 IgG antibodies were considered as the primary endpoint. The occurrence of adverse events after vaccination and objective deterioration of chronic graft-versus-host disease (GVHD) were defined as secondary endpoints. In addition, we compared the geometric mean titers (GMT) of anti-S1 antibody titers in subgroups based on time interval between transplantation and vaccination.

RESULTS

A humoral response to the vaccine was evident in 40 (91%) patients and all 38 healthy controls. The GMT of anti-S1 titers in patients and healthy controls were 277 (95% confidence interval [CI]: 120-643) BAU/mL and 532 (95% CI 400-708) BAU/mL, respectively. (p = 0.603). A short time interval between transplantation and vaccination (≤6 months) was associated with low anti-S1 IgG antibody titers. No serious adverse events and deterioration of chronic GVHD were observed. Only one case of new development of mild chronic GVHD was recorded.

CONCLUSION

Messenger RNA COVID-19 vaccines induce humoral responses in allo-HSCT recipients and can be administered safely.

Response to COVID-19 vaccination post CAR T therapy in patients with non-Hodgkin lymphoma and multiple myeloma

COVID-19 adversely affects individuals with cancer. Several studies have found that seroconversion rates among patients with hematologic malignancies are suboptimal when compared to patients without cancer. Patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) are immunocompromised due to impaired humoral and cellular immunity in addition to prescribed immunosuppressive therapy. Chimeric antigen receptor T-cell (CAR T) therapy is now widely used for NHL and MM, but little is known about seroconversion rates after COVID-19 vaccination among these populations. We evaluated SARS-CoV-2 spike-binding IgG antibody levels following COVID-19 vaccination among NHL and MM CAR T therapy recipients. Out of 104 CAR T infusions, 19 patients developed known COVID-19 infection post-CAR T. We tested 17 patients that received CAR T for antibody spike titers post COVID-19 vaccination, only 29 % (n = 5) were able to mount a clinically relevant antibody response (>250 IU/mL).

Effectiveness and Safety of COVID-19 Vaccination in Patients with Malignant Disease

A novel virus named SARS-CoV-2 has caused a worldwide pandemic, resulting in a disastrous impact to the public health since 2019. The disease is much more lethal among patients with malignant disease. Vaccination plays an important role in the prevention of infection and subsequent severe COVID-19. However, the efficacy and safety of vaccines for cancer patients needs further investigation. Encouragingly, there have been important findings deduced from research so far. In this review, an overview of the immunogenicity, effectiveness, and safeness of COVID-19 vaccines in patients with cancer to date is to be shown. We also highlight important questions to consider and directions that could be followed in future research.

Antibody, cell-mediated response and infection susceptibility in allogeneic hematopoietic stem cell recipients after COVID-19 mRNA vaccination

BACKGROUND

Patients undergoing allogeneic stem-cell transplantation (allo-SCT) have reduced responses to vaccines due to immunosuppressive status linked to GvHD prophylaxis and treatment. In our study, we compared humoral responses to anti-SARS-CoV-2 mRNA vaccine, and infection onset, according to patients and transplant features; we also evaluated cellular response in patients without seroconversion.

METHODS

We tested antibodies titer after second and third vaccine doses. Antibodies were detected through an immune-enzymatic assay. In a patients' subgroup without seroconversion, we tested cell-mediated responses evaluating interferon-gamma release by T-lymphocytes exposed to virus spike protein.

RESULTS

Seroconversion rate increased from 66% at 30 days to 81% at 90 days after the second dose; it was 97% at 150 days after the third dose. We found a significant association between seroconversion after the second dose and two variables: shorter interval between allo-SCT and vaccination; ongoing immunosuppression. Twelve of 19 patients (63%) without antibodies after the second dose did not show cellular responses. Nineteen percent of patients developed SARS-CoV-2 infection after the third dose, with favorable outcome in all cases. Patients within 12 months after allo-SCT showed a significantly higher infection risk.

CONCLUSIONS

Our study suggests that an interval shorter than 12 months between allo-SCT and first vaccine dose and/or ongoing immunosuppression were associated with humoral and cellular response deficiency after two doses. Third dose induced an increased and sustained humoral response in the majority of patients. However, patients within 1 year after allo-SCT remained at higher infection risk and may be candidate for prophylaxis with anti-SARS-CoV-2 monoclonal antibodies.

SARS-CoV-2-Specific T Cell Responses in Immunocompromised Individuals with Cancer, HIV or Solid Organ Transplants

Adaptive immune responses play an important role in the clinical course of SARS-CoV-2 infection. While evaluations of the virus-specific defense often focus on the humoral response, cellular immunity is crucial for the successful control of infection, with the early development of cytotoxic T cells being linked to efficient viral clearance. Vaccination against SARS-CoV-2 induces both CD4+ and CD8+ T cell responses and permits protection from severe COVID-19, including infection with the currently circulating variants of concern. Nevertheless, in immunocompromised individuals, first data imply significantly impaired SARS-CoV-2-specific immune responses after both natural infection and vaccination. Hence, these high-risk groups require particular consideration, not only in routine clinical practice, but also in the development of future vaccination strategies. In order to assist physicians in the guidance of immunocompromised patients, concerning the management of infection or the benefit of (booster) vaccinations, this review aims to provide a concise overview of the current knowledge about SARS-CoV-2-specific cellular immune responses in the vulnerable cohorts of cancer patients, people living with HIV (PLWH), and solid organ transplant recipients (SOT). Recent findings regarding the virus-specific cellular immunity in these differently immunocompromised populations might influence clinical decision-making in the future.

SARS-CoV-2 infections in pediatric and young adult recipients of chimeric antigen receptor T-cell therapy: an international registry report

BACKGROUND

Immunocompromised patients are at increased risk of SARS-CoV-2 infections. Patients undergoing chimeric antigen receptor (CAR) T-cell therapy for relapsed/refractory B-cell malignancies are uniquely immunosuppressed due to CAR T-mediated B-cell aplasia (BCA). While SARS-CoV-2 mortality rates of 33%-40% are reported in adult CAR T-cell recipients, outcomes in pediatric and young adult CAR T-cell recipients are limited.

METHODS

We created an international retrospective registry of CAR T recipients aged 0-30 years infected with SARS-CoV-2 within 2 months prior to or any time after CAR T infusion. SARS-CoV-2-associated illness was graded as asymptomatic, mild, moderate, or severe COVID-19, or multisystem inflammatory syndrome in children (MIS-C). To assess for risk factors associated with significant SARS-CoV-2 infections (infections requiring hospital admission for respiratory distress or supplemental oxygen), univariate and multivariable regression analyses were performed.

RESULTS

Nine centers contributed 78 infections in 75 patients. Of 70 SARS-CoV-2 infections occurring after CAR T infusion, 13 (18.6%) were classified as asymptomatic, 37 (52.9%) mild, 11 (15.7%) moderate, and 6 (8.6%) severe COVID-19. Three (4.3%) were classified as MIS-C. BCA was not significantly associated with infection severity. Prior to the emergence of the Omicron variant, of 47 infections, 19 (40.4%) resulted in hospital admission and 7 (14.9%) required intensive care, while after the emergence of the Omicron variant, of 23 infections, only 1 (4.3%) required admission and the remaining 22 (95.7%) had asymptomatic or mild COVID-19. Death occurred in 3 of 70 (4.3%); each death involved coinfection or life-threatening condition. In a multivariable model, factors associated with significant SARS-CoV-2 infection included having two or more comorbidities (OR 7.73, CI 1.05 to 74.8, p=0.048) and age ≥18 years (OR 9.51, CI 1.90 to 82.2, p=0.014). In the eight patients infected with SARS-CoV-2 before CAR T, half of these patients had their CAR T infusion delayed by 15-30 days.

CONCLUSIONS

In a large international cohort of pediatric and young adult CAR-T recipients, SARS-CoV-2 infections resulted in frequent hospital and intensive care unit admissions and were associated with mortality in 4.3%. Patients with two or more comorbidities or aged ≥18 years were more likely to experience significant illness. Suspected Omicron infections were associated with milder disease.

Three doses of BNT162b2 COVID-19 mRNA vaccine establish long-lasting CD8+ T cell immunity in CLL and MDS patients

Patients with hematological malignancies are prioritized for COVID-19 vaccine due to their high risk for severe SARS-CoV-2 infection-related disease and mortality. To understand T cell immunity, its long-term persistence, and its correlation with antibody response, we evaluated the BNT162b2 COVID-19 mRNA vaccine-specific immune response in chronic lymphocytic leukemia (CLL) and myeloid dysplastic syndrome (MDS) patients. Longitudinal analysis of CD8⁺ T cells using DNA-barcoded peptide-MHC multimers covering the full SARS-CoV-2 Spike-protein (415 peptides) showed vaccine-specific T cell activation and persistence of memory T cells up to six months post-vaccination. Surprisingly, a higher frequency of vaccine-induced antigen-specific CD8⁺ T cells was observed in the patient group compared to a healthy donor group. Furthermore, and importantly, immunization with the second booster dose significantly increased the frequency of antigen-specific CD8⁺ T cells as well as the total number of T cell specificities. Altogether 59 BNT162b2 mRNA vaccine-derived immunogenic responses were identified, of which 23 established long-term CD8⁺ T cell memory response with a strong immunodominance for NYNYLYRLF (HLA-A24:02) and YLQPRTFLL (HLA-A02:01) epitopes. In summary, we mapped the vaccine-induced antigen-specific CD8⁺ T cells and showed a booster-specific activation and enrichment of memory T cells that could be important for long-term disease protection in this patient group.

Improved outcomes over time and higher mortality in CMV seropositive allogeneic stem cell transplantation patients with COVID-19; An infectious disease working party study from the European Society for Blood and Marrow Transplantation registry

Introduction

COVID-19 has been associated with high morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HCT) recipients.

Methods

This study reports on 986 patients reported to the EBMT registry during the first 29 months of the pandemic.

Results

The median age was 50.3 years (min - max; 1.0 - 80.7). The median time from most recent HCT to diagnosis of COVID-19 was 20 months (min - max; 0.0 - 383.9). The median time was 19.3 (0.0 - 287.6) months during 2020, 21.2 (0.1 - 324.5) months during 2021, and 19.7 (0.1 - 383.9) months during 2022 (p = NS). 145/986 (14.7%) patients died; 124 (12.6%) due to COVID-19 and 21 of other causes. Only 2/204 (1%) fully vaccinated patients died from COVID-19. There was a successive improvement in overall survival over time. In multivariate analysis, increasing age (p<.0001), worse performance status (p<.0001), contracting COVID-19 within the first 30 days (p<.0001) or 30 - 100 days after HCT (p=.003), ongoing immunosuppression (p=.004), pre-existing lung disease (p=.003), and recipient CMV seropositivity (p=.004) had negative impact on overall survival while patients contracting COVID-19 in 2020 (p<.0001) or 2021 (p=.027) had worse overall survival than patients with COVID-19 diagnosed in 2022.

Discussion

Although the outcome of COVID-19 has improved, patients having risk factors were still at risk for severe COVID-19 including death.

Allogeneic hematopoietic stem cell transplantation in the COVID-19 era

Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) recipients are especially vulnerable to coronavirus disease 19 (COVID-19), because of their profound immunodeficiency. Indeed, the first pandemic wave was marked by a high mortality rate in this population. Factors increasing immunodepression such as older age, immunosuppressive treatments or a short delay between transplant and infection appear to worsen the prognosis. Many changes in clinical practice had to be implemented in order to limit this risk, including postponing of transplant for non-malignant diseases, preference for local rather than international donations and for peripheral blood as stem cell source, and the widespread use of cryopreservation. The great revolution in the COVID-19 pandemic came from the development of mRNA vaccines that have shown to be able to prevent severe forms of the disease. More than 75% of allo-HSCT recipients develop seroconversion after 2 doses of vaccine. Multiple studies have identified lymphopenia, exposure to immunosuppressive or anti-CD20 therapies, and a short post-transplant period as factors associated with a poor response to vaccination. The use of repeated injections of the vaccine, including a third dose, not only improves the seroconversion rate but also intensifies the immune response, both in B cells and T cells. Vaccines are an effective and well-tolerated method in this high-risk population. Some studies investigated the possibility of immune protection being transferred from a vaccinated donor to a recipient, with encouraging initial results. However, dynamic mutations and immune escape of the virus can lead to breakthrough infections with new variants in vaccinated individuals and still represent a threat of severe disease in allo-HSCT recipients. New challenges include the need to adapt vaccine protection to emerging variants.

Predictors of impaired antibody response after SARS-CoV-2 mRNA vaccination in hematopoietic cell transplant recipients: A Japanese multicenter observational study

HCT recipients reportedly have a high mortality rate after developing COVID-19. SARS-CoV-2 vaccination is generally useful to prevent COVID-19. However, its safety and efficacy among HCT recipients remain elusive. This large-scale prospective observational study including 543 HCT recipients with 37-months interval from transplant demonstrated high safety profiles of mRNA vaccine: only 0.9% of patients avoided the second dose due to adverse event or GVHD aggravation following the first dose. Regarding the efficacy, serological response with a clinically relevant titer (≥250 BAU/mL) was obtained in 397 (73.1%) patients. We classified the remaining 146 patients as impaired responders and compared the clinical and immunological parameters between two groups. In allogeneic HCT recipients, multivariable analysis revealed the risk factors for impaired serological response as follows: age (≥60, 1 points), HLA-mismatched donor (1 points), use of systemic steroids (1 points), absolute lymphocyte counts (<1000/μL, 1 points), absolute B-cell counts (<100/μL, 1 points), and serum IgG level (<500 mg/dL, 2 points). Notably, the incidence of impaired serological response increased along with the risk scores: patients with 0, 1-3, and 4-7 points were 3.9%, 21.8%, and 74.6%, respectively. In autologous HCT recipients, a shorter interval from transplant to vaccination was the only risk factor for impaired serological response. Our findings indicate that two doses of SARS-CoV-2 vaccine are safe but insufficient for a part of HCT recipients with higher risk scores. To improve this situation, we should consider additional treatment options, including booster vaccination and prophylactic neutralizing antibodies during the SARS-CoV-2 pandemic.

Neutropenia Secondary to SARS-Cov2 Vaccination in Post-Hematopoietic Stem Cell Transplant (HSCT) Patients

SARS-Cov2 s, caused a high mortality in patients with some degree of immunosuppression, like those that receive a hematopoietic progenitor transplant. Since December 2020, several vaccines have been developed having been key in decreasing complications and mortality in this group of patients. Different articles have described the presence of thrombopenia related to the administration of vaccines, however, there are few data on the occurrence of neutropenia as a side effect after administration. We present several cases of neutropenia (defined as absolute neutrophil count (ANC) less than 2,000/mm3), after vaccination in hematopoietic progenitor transplant (HPT) recipients performed in our center during 2021.  

Joint consensus statement on the vaccination of adult and paediatric haematopoietic stem cell transplant recipients: Prepared on behalf of the British society of blood and marrow transplantation and cellular therapy (BSBMTCT), the Children's cancer and Leukaemia Group (CCLG), and British Infection Association (BIA)

Haematopoietic stem cell transplant (HSCT) recipients have deficiencies in their adaptive immunity against vaccine preventable diseases. National and International guidance recommends that HSCT recipients are considered 'never vaccinated' and offered a comprehensive course of revaccination. This position statement aims to draw upon the current evidence base and existing guidelines, and align this with national vaccine availability and licensing considerations in order to recommend a pragmatic and standardised re-vaccination schedule for adult and paediatric HSCT recipients in the UK.

Immunogenicity and risks associated with impaired immune responses following SARS-CoV-2 vaccination and booster in hematologic malignancy patients: an updated meta-analysis

Patients with hematologic malignancies (HM) have demonstrated impaired immune responses following SARS-CoV-2 vaccination. Factors associated with poor immunogenicity remain largely undetermined. A literature search was conducted using PubMed, EMBASE, Cochrane, and medRxiv databases to identify studies that reported humoral or cellular immune responses (CIR) following complete SARS-CoV-2 vaccination. The primary aim was to estimate the seroconversion rate (SR) following complete SARS-CoV-2 vaccination across various subtypes of HM diseases and treatments. The secondary aims were to determine the rates of development of neutralizing antibodies (NAb) and CIR following complete vaccination and SR following booster doses. A total of 170 studies were included for qualitative and quantitative analysis of primary and secondary outcomes. A meta-analysis of 150 studies including 20,922 HM patients revealed a pooled SR following SARS-CoV-2 vaccination of 67.7% (95% confidence interval [CI], 64.8-70.4%; I2 = 94%). Meta-regression analysis showed that patients with lymphoid malignancies, but not myeloid malignancies, had lower seroconversion rates than those with solid cancers (R2 = 0.52, P < 0.0001). Patients receiving chimeric antigen receptor T-cells (CART), B-cell targeted therapies or JAK inhibitors were associated with poor seroconversion (R2 = 0.39, P < 0.0001). The pooled NAb and CIR rates were 52.8% (95% CI; 45.8-59.7%, I2 = 87%) and 66.6% (95% CI, 57.1-74.9%; I2 = 86%), respectively. Approximately 20.9% (95% CI, 11.4-35.1%, I2 = 90%) of HM patients failed to elicit humoral and cellular immunity. Among non-seroconverted patients after primary vaccination, only 40.5% (95% CI, 33.0-48.4%; I2 = 87%) mounted seroconversion after the booster. In conclusion, HM patients, especially those with lymphoid malignancies and/or receiving CART, B-cell targeted therapies, or JAK inhibitors, showed poor SR after SARS-CoV-2 vaccination. A minority of patients attained seroconversion after booster vaccination. Strategies to improve immune response in these severely immunosuppressed patients are needed.

Evidence of exhausted lymphocytes after the third anti-SARS-CoV-2 vaccine dose in cancer patients

Introduction

Evidence is scant regarding the long-term humoral and cellular responses Q7 triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in cancer patients after repeated booster doses. The possibility of T-cell exhaustion following these booster doses in this population has not yet been fully studied and remains uncertain.

Methods

In this single-center prospective observational study, we explored the specific humoral and cellular response to S1 antigen in 36 patients with solid malignancies at baseline, and after the second and third doses of the mRNA-1273 vaccine.

Results

A dual behavior was observed: 24 (66.7%) patients showed partial specific IFN-γ response after the second dose that was further enhanced after the third dose; and 11 (30.5%) already showed an optimal response after the second dose and experienced a marked fall-off of specific IFN-γ production after the third (4 patients negativization), which might suggest T cell exhaustion due to repetitive priming to the same antigen. One (2.8%) patient had persistently negative responses after all three doses. Seroconversion occurred in all patients after the second dose. We then studied circulating exhausted CD8+ T-cells in 4 patients from each of the two response patterns, those with increase and those with decrease in cellular response after the third booster. The patients with decreased cellular response after the booster had a higher expression of PD1⁺CD8⁺ and CD57⁺PD1⁺CD8⁺ exhausted T cells compared with those with an increased cellular response both in vivo and in vitro. The proportion of PD1⁺CD8⁺ and CD57⁺PD1⁺CD8⁺ exhausted T cells inversely correlated with IFN-γ production.

Discussion

Our preliminary data show that the two-dose SARS-CoV-2 vaccine regimen was beneficial in all cancer patients of our study. An additional booster seems to be beneficial in suboptimal vaccine seroconverters, in contrast to maximal responders that might develop exhaustion. Our data should be interpreted with caution given the small sample size and highlight the urgent need to validate our results in other independent and larger cohorts. Altogether, our data support the relevance of immunological functional studies to personalize preventive and treatment decisions in cancer patients.

A review of COVID vaccines: success against a moving target

BACKGROUND

Multiple vaccine platforms against COVID-19 have been developed and found safe and efficacious at a record speed. Although most are effective, they vary in their ease of production and distribution, their potential speed of modification against new variants, and their durability of protection and safety in certain target groups.

SOURCES OF DATA

Our discussion is based on published reports of clinical trials and analyses from national and global health agencies.

AREAS OF AGREEMENT

The production of neutralizing antibodies against the viral spike protein is protective, and all vaccines for which published data exist have been found to be effective against severe disease caused by the viral strain they target.

AREAS OF CONTROVERSY

The degree to which vaccines protect against emerging variants, moderate disease and asymptomatic infection remains somewhat unclear.

GROWING POINTS

Knowledge of the duration of protection and its decay is increasing, and discussions of booster frequency and target strains are ongoing.

AREAS TIMELY FOR DEVELOPING RESEARCH

The global effort to combat transmission and disease continues to rely upon intense epidemiological surveillance, whilst real-world data and clinical trials shape vaccination schedules and formulae.

Antibody response after vaccination against SARS-CoV-2 in adults with hematological malignancies: a systematic review and meta-analysis

Vaccines against SARS-CoV-2 have shown remarkable efficacy and thus constitute an important preventive option against coronavirus disease 2019 (COVID-19), especially in fragile patients. We aimed to systematically analyze the outcomes of patients with hematological malignancies who received vaccination and to identify specific groups with differences in outcomes. The primary end point was antibody response after full vaccination (2 doses of mRNA or one dose of vector- based vaccines). We identified 49 studies comprising 11,086 individuals. Overall risk of bias was low. The pooled response for hematological malignancies was 64% (95% confidence interval [CI]: 59-69; I²=93%) versus 96% (95% CI: 92-97; I²=44%) for solid cancer and 98% (95% CI: 96-99; I²=55%) for healthy controls (P<0.001). Outcome was different across hematological malignancies (P<0.001). The pooled response was 50% (95% CI: 43-57; I²=84%) for chronic lymphocytic leukemia, 76% (95% CI: 67-83; I²=92%) for multiple myeloma, 83% (95% CI: 69-91; I²=85%) for myeloproliferative neoplasms, 91% (95% CI: 82-96; I²=12%) for Hodgkin lymphoma, and 58% (95% CI: 44-70; I²=84%) for aggressive and 61% (95% CI: 48-72; I²=85%) for indolent non-Hodgkin lymphoma. The pooled response for allogeneic and autologous hematopoietic cell transplantation was 82% and 83%, respectively. Being in remission and prior COVID-19 showed significantly higher responses. Low pooled response was identified for active treatment (35%), anti-CD20 therapy ≤1 year (15%), Bruton kinase inhibition (23%), venetoclax (26%), ruxolitinib (42%), and chimeric antigen receptor T-cell therapy (42%). Studies on timing, value of boosters, and long-term efficacy are needed. This study is registered with PROSPERO (clinicaltrials gov. Identifier: CRD42021279051).

Antibody response to a third SARS‐CoV‐2 vaccine dose in recipients of an allogeneic haematopoietic cell transplantation

Allogeneic haematopoietic cell transplantation (allo-HCT) recipients show impaired antibody (Ab) response to a standard two-dose vaccination against severe acute respiratory syndrome coronavirus-2 and currently a third dose is recommended as part of the primary vaccination regimen. By assessing Ab titres 1 month after a third mRNA vaccine dose in 74 allo-HCT recipients we show sufficient neutralisation activity in 77% of the patients. Discontinuation of immunosuppression before the third vaccine led to serological responses in 50% of low responders to two vaccinations. Identifying factors that might contribute to better vaccine responses in allo-HCT recipients is critical to optimise current vaccination strategies.

COVID-19 vaccine response and safety in patients with cancer: An overview of systematic reviews

Background

To date, the COVID-19 pandemic does not appear to be overcome with new variants continuously emerging. The vaccination against COVID-19 has been the trend, but there are multiple systematic reviews on COVID-19 vaccines in patients with cancer, resulting in redundant and sub-optimal systematic reviews. There are still some doubts about efficacy and safety of the COVID-19 vaccine in cancer patients.

Purpose

To identify, summarize and synthesize the available evidence of systematic reviews on response and COVID-19 vaccine safety in patients with cancer.

Methods

Multiple databases were searched from their inception to May 1, 2022 to fetch the relevant articles. Study quality was assessed by AMSTAR2. The protocol of this study was registered on PROSPERO (CRD42022327931).

Results

A total of 18 articles were finally included. The seroconversion rates after first dose were ranged from 37.30-54.20% in all cancers, 49.60-62.00% in solid cancers and 33.30-56.00% in hematological malignancies. The seroconversion rates after second dose were ranged from 65.30-87.70% in all cancers, 91.60-96.00% in solid cancers and 58.00-72.60% in hematological malignancies. Cancer types and types of therapy could influence vaccine response. COVID-19 vaccines were safe and well-tolerated.

Conclusions

This study suggests COVID-19 vaccine response is significantly lower in cancer patients. Number of received doses, cancer types and treatment strategies could influence response of COVID-19 vaccine in cancer patients. COVID-19 vaccines are safe and well-tolerated. Considering the emergence of several new variants of SARS-CoV-2 with potential influence on ongoing vaccination programs, there is a need for booster doses to increase the effectiveness of COVID-19 vaccines.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022327931, identifier CRD42022327931.

Adaptive humoral immune response and cellular immune status in cancer patients and patients under immunosuppression vaccinated against SARS-CoV-2

BACKGROUND

Patients with cancer and autoimmune diseases are at higher risk of severe COVID-19. They may not develop protective immune responses following vaccination. We investigated patients' cellular and humoral immune response after two COVID-19 vaccine doses.

RESEARCH DESIGN AND METHODS

Subjects were stratified into subgroups according to therapy and grade of immunosuppression at time of vaccination.

RESULTS

Antibody titers were compared to healthy controls. 32/122 (26%) did not develop detectable antibody titers. Of these, 22 (66.6%) had active therapy. Patients showed significant lower antibody titers compared to controls (median 790 vs. 3923 AU/mL, p = 0.026). Patients with active therapy had significant lower antibody titers compared to those without (median 302 vs. 3952 U/L P < 0.001). B-cell count was lower in the group without antibody titers (median 29.97 vs. 152.8; p = 0.002). 100% of patients under anti-CD20 therapy had no detectable antibody titer, followed by anti-TNF (66%), BTK inhibitors (50%), ruxolitinib (35.5%), TKI (14.2%), and lenalidomide (12.5%). Anti-CD20 therapy, ruxolitinib, BTK inhibitors, and anti-CD38 therapy presented significant lower antibody titers compared to controls.

CONCLUSIONS

Patients undergoing therapy for cancer or autoimmune diseases are at higher risk of insufficient humoral immune response following COVID-19 vaccination. Furthermore, alterations in the B-cell compartment correlate with lower antibody titers.

A Third Dose COVID-19 Vaccination in Allogeneic Hematopoietic Stem Cell Transplantation Patients

We previously reported that a second dose of BNT162b2 was safe and effective for allogeneic hematopoietic stem cell transplantation (HSCT) patients. Here, we investigated the safety and efficacy of a third dose of COVID-19 mRNA vaccine in allogeneic HSCT patients. Antibody titers against the S1 spike protein were measured using the QuaResearch COVID-19 Human IgM IgG ELISA kit. The previous study included 25 allogeneic HSCT patients who received two doses of BNT162b2. Following the exclusion of three patients because of the development of COVID-19 (n = 2) and loss to follow-up (n = 1), the study evaluated 22 allogeneic HSCT patients who received a third dose of COVID-19 mRNA vaccine (BNT162b2 [n = 15] and mRNA-1273 [n = 7]). Median age at the time of the first vaccination was 56 (range, 23-71) years. Five patients were receiving immunosuppressants at the third vaccination, namely calcineurin inhibitors (CI) alone (n = 1), steroids alone (n = 2), or CI combined with steroids (n = 2). Twenty-one patients (95%) seroconverted after the third dose. None of our patients had serious adverse events, new-onset graft-versus-host disease (GVHD), or GVHD exacerbation after vaccination. A third dose of the BNT162b2 and mRNA-1273 COVID-19 vaccines was safe and effective for allogeneic HSCT patients.

Cellular and Humoral SARS-CoV-2 Vaccination Responses in 192 Adult Recipients of Allogeneic Hematopoietic Cell Transplantation

To determine factors influencing the vaccination response against SARS-CoV-2 is of importance in recipients of allogeneic hematopoietic cell transplantation (allo-HCT) as they display an increased mortality after SARS-CoV-2 infection, an increased risk of extended viral persistence and reduced vaccination response. Real-life data on anti-SARS-CoV-2-S1-IgG titers (n = 192) and IFN-γ release (n = 110) of allo-HCT recipients were obtained using commercially available, validated assays after vaccination with either mRNA (Comirnaty™, Pfizer-BioNTech™, NY, US and Mainz, Germany or Spikevax™, Moderna™, Cambridge, Massachusetts, US) or vector-based vaccines (Vaxzevria™,AstraZeneca™, Cambridge, UK or Janssen COVID-19 vaccine™Johnson/Johnson, New Brunswick, New Jersey, US), or after a heterologous protocol (vector/mRNA). Humoral response (78% response rate) was influenced by age, time after transplantation, the usage of antithymocyte globulin (ATG) and ongoing immunosuppression, specifically corticosteroids. High counts of B cells during the vaccination period correlated with a humoral response. Only half (55%) of participants showed a cellular vaccination response. It depended on age, time after transplantation, ongoing immunosuppression with ciclosporin A, chronic graft-versus-host disease (cGvHD) and vaccination type, with vector-based protocols favoring a response. Cellular response failure correlated with a higher CD8+ count and activated/HLA-DR+ T cells one year after transplantation. Our data provide the basis to assess both humoral and cellular responses after SARS-CoV2 vaccination in daily practice, thereby opening up the possibility to identify patients at risk.

Attenuated humoral response against SARS-CoV-2 mRNA vaccination in allogeneic stem cell transplantation recipients

Antibody persistence several months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination in allogeneic stem cell transplantation recipients remains largely unknown. We sequentially evaluated the humoral response to two doses of mRNA vaccines in 128 adult recipients and identified the risk factors involved in a poor response. The median interval between stem cell transplantation and vaccination was 2.7 years. The SARS-CoV-2 S1 Ab became positive after the second vaccination dose in 87.6% of the recipients, and the median titer was 1235.4 arbitrary units (AU)/ml. In patients on corticosteroid treatment, the corticosteroid dose inversely correlated with Ab titer. Multivariate analysis identified risk factors for poor peak response such as an interval from stem cell transplantation ≤1 year, history of clinically significant CMV infection, and use of >5 mg/day prednisolone at vaccination. Six months after vaccination, the median titer decreased to 185.15 AU/ml, and use of >5 mg/day prednisolone at vaccination was significantly associated with a poor response. These results indicate that early vaccination after stem cell transplantation (<12 months) and CMV infection are risk factors for poor peak response, while steroid use is important for a peak as well as a persistent response. In conclusion, although humoral response is observed in many stem cell transplantation recipients after two doses of vaccination, Ab titers diminish with time, and factors associated with persistence and a peak immunity should be considered separately.