Risk factors and characteristics influencing humoral response to COVID-19 vaccination in patients after allogeneic stem cell transplantation

Impact of Immunosuppressants and Vaccination on COVID-19 Outcomes in Autoimmune Patients and Solid Organ Transplant Recipients: A Nationwide Propensity Score-Matched Study

PURPOSE

This study investigates the impact of varying degrees of immunosuppression on the clinical outcomes of immunocompromised individuals, particularly those with autoimmune diseases or post-solid organ transplant statuses, in the context of COVID-19. By focusing on these highly vulnerable populations, the study underscores the significant health inequalities faced by immunocompromised patients, who experience disproportionately worse outcomes in comparison to the general population.

METHODS

A retrospective cohort analysis of the K-COV-N dataset was conducted, comparing the effects of immunosuppression in autoimmune and transplant groups with matched control groups. Propensity score matching was employed to minimize inequalities in baseline characteristics, ensuring a more equitable comparison between immunocompromised and non-immunocompromised individuals. Outcomes included COVID-19-related in-hospital mortality, 28-day mortality, ICU admissions, and the need for respiratory support among 323,890 adults in the Republic of Korea. Patients with cancer or other immunosuppressive conditions, such as HIV, were excluded. Subgroup analyses assessed the influence of specific immunosuppressive medications and vaccination extent.

RESULTS

Significantly elevated in-hospital mortality was found for patients with autoimmune diseases (adjusted Odds Ratio [aOR] 2.749) and transplant recipients (aOR 7.567), with similar patterns in other outcomes. High-dose steroid use and a greater number of immunosuppressant medications markedly increased the risk of poor outcomes. Vaccination emerged as a protective factor, with a single dose substantially improving outcomes for autoimmune patients and at least two doses necessary for transplant recipients.

CONCLUSIONS

Immunocompromised patients, particularly those with autoimmune diseases and transplant recipients, are highly vulnerable to severe COVID-19 outcomes. High-dose steroid use and multiple immunosuppressants further increase risks. Vaccination significantly improves outcomes, with at least one dose benefiting autoimmune patients and two doses necessary for transplant recipients. Personalized vaccination schedules based on immunosuppression levels are essential to mitigate healthcare inequalities and improve outcomes, particularly in underserved populations, informing both clinical and public health strategies.

Severe acute respiratory syndrome coronavirus 2 infection in patients with hematological malignancies in the Omicron era: Respiratory failure, need for mechanical ventilation and mortality in seronegative and seropositive patients

Background

Patients with hematological malignancies (HM) have a high risk of severe coronavirus disease 2019 (COVID-19), also in the Omicron period.

Material and methods

Retrospective single-center study including HM patients with severe acute respiratory syndrome Coronavirus 2 (SARS-CoV2) infection from January 2022 to March 2023. Study outcomes were respiratory failure (RF), mechanical ventilation (MV), and COVID-related mortality, comparing patients according to SARS-CoV2 serology.

Results

Note that, 112 patients were included: 39% had negative SARS-CoV2 serology. Seronegative were older (71.5 vs. 65.0 years, p = 0.04), had more often a lymphoid neoplasm (88.6% vs. 69.1%, p = 0.02), underwent anti-CD20 therapy (50.0% vs. 30.9% p = 0.04) and had more frequently a severe disease (23.0% vs. 3.0%, p = 0.02) than seropositive.Kaplan-Meier showed a higher risk for seronegative patients for RF (p = 0.014), MV (p = 0.044), and COVID-related mortality (p = 0.021). Negative SARS-CoV2 serostatus resulted in a risk factor for RF (hazards ratio [HR] 2.19, 95% confidence interval [CI] 1.03-4.67, p = 0.04), MV (HR 3.37, 95% CI 1.06-10.68, p = 0.04), and COVID-related mortality (HR 4.26, 95% CI 1.09-16.71, p = 0.04).

Conclusions

: HM patients with negative SARS-CoV2 serology, despite vaccinations and previous infections, have worse clinical outcomes compared to seropositive patients in the Omicron era. The use of serology for SARS-CoV2 diagnosis could be an easy tool to identify patients prone to developing complications.

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.

Comparable CD8+ T-cell responses to SARS-CoV-2 vaccination in single-cell transcriptomics of recently allogeneic transplanted patients and healthy individuals

Despite extensive research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination responses in healthy individuals, there is comparatively little known beyond antibody titers and T-cell responses in the vulnerable cohort of patients after allogeneic hematopoietic stem cell transplantation (ASCT). In this study, we assessed the serological response and performed longitudinal multimodal analyses including T-cell functionality and single-cell RNA sequencing combined with T cell receptor (TCR)/B cell receptor (BCR) profiling in the context of BNT162b2 vaccination in ASCT patients. In addition, these data were compared to publicly available data sets of healthy vaccinees. Protective antibody titers were achieved in 40% of patients. We identified a distorted B- and T-cell distribution, a reduced TCR diversity, and increased levels of exhaustion marker expression as possible causes for the poorer vaccine response rates in ASCT patients. Immunoglobulin heavy chain gene rearrangement after vaccination proved to be highly variable in ASCT patients. Changes in TCRα and TCRβ gene rearrangement after vaccination differed from patterns observed in healthy vaccinees. Crucially, ASCT patients elicited comparable proportions of SARS-CoV-2 vaccine-induced (VI) CD8+ T-cells, characterized by a distinct gene expression pattern that is associated with SARS-CoV-2 specificity in healthy individuals. Our study underlines the impaired immune system and thus the lower vaccine response rates in ASCT patients. However, since protective vaccine responses and VI CD8+ T-cells can be induced in part of ASCT patients, our data advocate early posttransplant vaccination due to the high risk of infection in this vulnerable group.

Vaccine schedule recommendations and updates for patients with hematologic malignancy post-hematopoietic cell transplant or CAR T-cell therapy

Revaccination after receipt of a hematopoietic cell transplant (HCT) or cellular therapies is a pillar of patient supportive care, with the potential to reduce morbidity and mortality linked to vaccine-preventable infections. This review synthesizes national, international, and expert consensus vaccination schedules post-HCT and presents evidence regarding the efficacy of newer vaccine formulations for pneumococcus, recombinant zoster vaccine, and coronavirus disease 2019 in patients with hematological malignancy. Revaccination post-cellular therapies are less well defined. This review highlights important considerations around poor vaccine response, seroprevalence preservation after cellular therapies, and the optimal timing of revaccination. Future research should assess the immunogenicity and real-world effectiveness of new vaccine formulations and/or vaccine schedules in patients post-HCT and cellular therapy, including analysis of vaccine response that relates to the target of cellular therapies.