Vaccination post-allogeneic hematopoietic stem cell transplantation: what is feasible?

Facilitators and Barriers to Successful Revaccination after Hematopoietic Stem Cell Transplantation among Adult Survivors: A Scoping Review

Post-transplantation revaccination uptake of childhood vaccines in adult hematopoietic stem cell transplantation (HSCT) survivors is suboptimal, increasing the risk of infectious morbidity and mortality within this population. We systematically reviewed the literature for factors related to revaccination uptake, as well as the barriers and facilitators that affect successful revaccination. We conducted a scoping review searching PubMed, CINAHL, Embase, and Web of Science in March 2023. Two independent reviewers performed study selection using the complete dual review process. Data were extracted using a standard form. Factors were characterized as demographic, clinical, or social determinants of health that affected revaccination uptake. Barriers and facilitators were categorized using the constructs from the World Health Organization Behavioural and Social Drivers Framework. Our searches yielded 914 sources, from which 15 publications were selected (5 original research and 10 quality improvement initiatives). More than one-half of the reports listed factors associated with poorer uptake, predominately clinical factors, followed by social determinants of health, then demographic factors. Nearly all the reports described barriers to successful revaccination uptake, with most of these falling into the "practical issues" construct. Most of the reports described facilitators, nearly all related to health care system improvements associated with improved revaccination uptake. Although this review provides a good starting point for understanding impediments to successful revaccination after HSCT, this review reveals that we lack sufficient evidence to drive targeted interventions to improve uptake. More research is needed, focusing on survivors' voices to inform our knowledge of barriers and facilitators to complete revaccination after HSCT, exploring behavioral and social drivers within this population, and examining the care delivery models that may complicate vaccine delivery in this population.

Reproductive late effects after hematopoietic stem cell transplant in pediatric, adolescent, and young adult cancer survivors

Reproductive late effects after hematopoietic stem cell transplant can have a significant impact on cancer survivors' quality of life. Potential late effects include gonadal insufficiency, genital graft-versus-host disease, uterine injury, psychosexual dysfunction, and an increased risk of breast and cervical cancer in patients treated with total body irradiation. Despite guidelines, screening and treatment are not standardized among at-risk patients. Provider barriers include lack of knowledge of at-risk therapies and evidenced-based guidelines. Patient barriers include a reluctance to report symptoms and lack of awareness of treatment options. System barriers include inefficient implementation of screening tools and poor dissemination of guidelines to providers who serve as the medical home for survivors. This review guides the clinician in identifying and managing reproductive late effects after hematopoietic stem cell transplant to improve outcomes.

Antibody Response against Vaccine Antigens in Children after TCRαβ-Depleted Haploidentical Stem Cell Transplantation: Is It Similar to That in Recipients with Fully Matched Donors?

Recipients of hematopoietic stem cell transplantation (HSCT) with HLA-mismatched donors are more immune suppressed than those with fully matched donors. The immunologic response to vaccines also may differ in HLA-mismatched haploidentical HSCT recipients. In this study, we aimed to evaluate the antibody response to vaccines in pediatric TCRαβ-depleted haploidentical HSCT recipients. This longitudinal study included a study group of 21 children who underwent haploidentical HSCT without CD19 depletion and with TCRαβ depletion and a control group of 38 children who underwent fully matched donor HSCT. Antibody levels were quantified by serologic tests before vaccination and after each dose against tetanus, diphtheria, pneumococcus, hepatitis B, hepatitis A, measles, rubella, mumps, and varicella. The median recipient age was significantly lower (P = .037) and the median donor age was significantly higher (P = .000) in the haploidentical group compared with the fully matched group. At the months 1, 3, 6, 9 and 12 post-transplantation, the median CD4, CD8, and CD19 cell counts and lymphocyte counts were similar in the haploidentical and fully matched groups. The median natural killer cell count was higher in the haploidentical group at the months 1, 3, and 6 post-transplantation (P = .001, .006, and .004, respectively). The median time to first vaccination was similar in the 2 groups (12.5 [range, 11 to 14] months for the haploidentical group and 11 [range, 9 to 13] months for the fully matched group; P = .441). Seroprotection rates were 100% in both groups after the second and third doses of diphtheria vaccine, the third dose of tetanus vaccine, the third dose of hepatitis B vaccine, the second and third doses of pneumococcal conjugate vaccines (PCV13), and pneumococcal polysaccharide vaccine (PSPV23), although lower after the initial doses and before vaccination. Seroprotection for hepatitis A, rubella, and varicella was >90% in the fully matched group and 100% for the haploidentical group after the second doses. Measles and mumps seroprotection rates were >80% in the haploidentical group and approximately 70% for the fully matched group after the second dose. Antibody response and seroprotection rates against vaccine antigens were similar in the haploidentical group and the fully matched when revaccination was started at 12 months post-transplantation. These findings support the idea that TCRαβ-depleted haploidentical HSCT recipients can be revaccinated according to the same vaccination schedule as fully matched HSCT recipients. Revaccination earlier after transplantation and vaccine responses for recipients of different types of HSCT should be evaluated in future studies.

Vaccine Responses in Adult Hematopoietic Stem Cell Transplant Recipients: A Comprehensive Review

Simple Summary

Patients who recently received a stem cell transplantation are at greater risk for infection due to impairment of their immune system. In order to prevent severe infection, these patients are vaccinated after their stem cell transplantation with childhood immunization vaccines. Timing of this vaccination is important in order to be effective and obtain proper immune response. Postponement of vaccination would lead to better immune response but would also cause longer-lasting risk of infection. This review describes available data on the timing of vaccination and its vaccine responses. Optimal timing of vaccination might require an individualized approach per patient.

Abstract

Consensus on timing of post-hematopoietic stem cell transplantation (HSCT) vaccination is currently lacking and is therefore assessed in this review. PubMed was searched systematically for articles concerning vaccination post-HSCT and included a basis in predefined criteria. To enable comparison, data were extracted and tables were constructed per vaccine, displaying vaccine response as either seroprotection or seroconversion for allogeneic HSCT (alloHSCT) and autologous HSCT (autoHSCT) separately. A total of 33 studies were included with 1914 patients in total: 1654 alloHSCT recipients and 260 autoHSCT recipients. In alloHSCT recipients, influenza vaccine at 7–48 months post-transplant resulted in responses of 10–97%. After 12 months post-transplant, responses were >45%. Pneumococcal vaccination 3–25 months post-transplant resulted in responses of 43–99%, with the response increasing with time. Diphtheria, tetanus, pertussis, poliomyelitis and Haemophilus influenzae type b at 6–17 months post-transplant: 26–100%. Meningococcal vaccination at 12 months post-transplant: 65%. Hepatitis B vaccine at 6–23 months post-transplant: 40–94%. Measles, mumps and rubella at 41–69 months post-transplant: 19–72%. In general, autoHSCT recipients obtained slightly higher responses compared with alloHSCT recipients. Conclusively, responses to childhood immunization vaccines post-HSCT are poor in comparison with healthy individuals. Therefore, evaluation of response might be indicated. Timing of revaccination is essential for optimal response. An individualized approach might be necessary for optimizing vaccine responses.

Humoral serological response to the BNT162b2 vaccine after allogeneic haematopoietic cell transplantation

Objectives

To assess the humoral immune response to the BNT162b2 vaccine after allogeneic haematopoietic cell transplantation (HCT).

Methods

This is a prospective cohort study. The SARS-CoV-2 IgGII Quant (Abbott©) assay was performed 4–6 weeks after the second BNT162b2 vaccine for quantitative measurement of anti-spike antibodies.

Results

The cohort included 106 adult patients. Median time from HCT to vaccination was 42 (range 4–439) months. Overall, 15/106 (14%, 95% confidence interval (CI) 7–21%) were seronegative despite vaccination, 14/52 patients on immunosuppression (27%, 95%CI 19–35%) compared to only 1/54 patients off immunosuppression (1.8%, 95%CI 1–4%) (p 0.0002). The proportion of seronegative patients declined with time; it was 46% (6/13) during the first year, 12.5% (3/24) during the second year and 9% (6/69) beyond 2 years from transplant. Patients with acute graft-versus-host disease (GVHD) (odds ratio (OR) 3.3, 95%CI 0.97–11.1, p 0.06) and moderate to severe chronic GVHD (OR 5.9, 95%CI 1.2–29, p 0.03) were more likely to remain seronegative. Vaccination was well tolerated by most patients. However, 7% (7/106) reported that GVHD-related symptoms worsened within days following vaccination.

Conclusion

A significant proportion of allogeneic HCT recipients receiving immunosuppression demonstrated an inadequate humoral response to the BNT162b2 vaccine. These patients should be recognized and instructed to take appropriate precautions. Recipients who were off immunosuppression had a humoral response that was comparable to that of the general population.

Prospective clinical trial of hepatitis B vaccination for children with hematological malignancies: a study on the safety and immunogenicity efficacy

Children with hematological malignancies are at increased risk of hepatitis B virus infection. This study assessed the immunogenicity and safety profile of HBV vaccination in pediatric hemato-oncological children. A nonrandomized interventional study was conducted from January 2017 to February 2020 in Shanghai, China. Seventy-three pediatric hemato-oncological children with hepatitis B surface antibody (anti-HBs) titers <10 mIU/ml were recruited. The participants received three doses of recombinant HBV vaccine according to the 0-, 1-, and 6- month immunization schedule. Adverse events following immunization and anti-HBs titers (at baseline, 1 month, and 6 months after inoculation) were recorded. Forty-three males and thirty females with median ages of 9.12 and 9.60 years, respectively, were included. The mean anti-HBs titer was 4.88 ± 2.61 mIU/ml, 893.12 ± 274.12 mIU/ml, and 711.45 ± 337.88 mIU/ml at baseline, one month, and six months after inoculation, respectively (P< .001). A total of fourteen adverse events following immunization were reported, and among them, 5 (6.85%), 5 (6.85%), and 4 (5.48%) events were reported after the first, second, and third inoculation, respectively (P= .927). In conclusions, the HBV vaccine is immunogenic and safe in children with hematological malignancies. It is worth noting that the anti-HBs titer was decreased at the 6-month follow-up, and periodic monitoring of the anti-HBs titer accompanied by timely booster vaccination should be carefully considered.Abbreviations: AEFI: Adverse events following immunization; HBV: Hepatitis B virus; Anti-HBs: Antibody against hepatitis B surface antigen; HBsAg: Hepatitis B surface antigen; APC: Antigen-presenting cell; HSCT: Hemopoietic stem cell transplantation; COVID-19: Corona Virus Disease 2019.

Immune Response Following Quadrivalent Human Papillomavirus Vaccination in Women After Hematopoietic Allogeneic Stem Cell Transplant: A Nonrandomized Clinical Trial

Importance

Human papillomavirus (HPV) infection is found in about 40% of women who survive allogeneic hematopoietic stem cell transplant and can induce subsequent neoplasms.

Objective

To determine the safety and immunogenicity of the quadrivalent HPV vaccine (HPV-6, -11, -16, and -18) in clinically stable women post-allogeneic transplant compared with female healthy volunteers.

Interventions

Participants received the quadrivalent HPV vaccine in intramuscular injections on days 1 and 2 and then 6 months later.

Design, Setting, and Participants

This prospective, open-label phase-1 study was conducted in a government clinical research hospital and included clinically stable women posttransplant who were or were not receiving immunosuppressive therapy compared with healthy female volunteers age 18 to 50 years who were followed up or a year after first receiving quadrivalent HPV vaccination. The study was conducted from June 2, 2010, until July 19, 2016. After all of the results of the study assays were completed and available in early 2018, the analysis took place from February 2018 to May 2019.

Main Outcomes and Measures

Anti-HPV-6, -11, -16, and -18-specific antibody responses using L1 virus-like particle enzyme-linked immunosorbent assay were measured in serum before (day 1) and at months 7 and 12 postvaccination. Anti-HPV-16 and -18 neutralization titers were determined using a pseudovirion-based neutralization assay.

Results

Of 64 vaccinated women, 23 (35.9%) were receiving immunosuppressive therapy (median age, 34 years [range, 18-48 years]; median 1.2 years posttransplant), 21 (32.8%) were not receiving immunosuppression (median age, 32 years [range, 18-49 years]; median 2.5 years posttransplant), and 20 (31.3%) were healthy volunteers (median age, 32 years [range, 23-45 years]). After vaccine series completion, 18 of 23 patients receiving immunosuppression (78.3%), 20 of 21 not receiving immunosuppression (95.2%), and all 20 volunteers developed antibody responses to all quadrivalent HPV vaccine types (P = .04, comparing the 3 groups). Geometric mean antibody levels for each HPV type were higher at months 7 and 12 than at baseline in each group (all geometric mean ratios >1; P < .001) but not significantly different across groups. Antibody and neutralization titers for anti-HPV-16 and anti-HPV-18 correlated at month 7 (Spearman ρ = 0.92; P < .001 for both). Adverse events were mild and not different across groups.

Conclusions and Relevance

Treatment with the HPV vaccination was followed by strong, functionally active antibody responses against vaccine-related HPV types and no serious adverse events. These findings suggest that HPV vaccination may be safely administered to women posttransplant to potentially reduce HPV infection and related neoplasia.

Trial Registration

ClinicalTrials.gov Identifier: NCT01092195.

Immune Status Against Hepatitis B in Patients After Allogeneic Hematopoietic Cell Transplantation-Factors Affecting Early and Long-Lasting Maintenance of Protective Anti-HBs Titers

The immunization of allogeneic hematopoietic cell transplantation (HCT) recipients against vaccine-preventable diseases is a part of posttransplantation guidelines. We conducted a prospective study to assess clinical and immunological parameters that would determine the response and long-term maintenance of protective antibody titers upon the hepatitis B virus (HBV) vaccination after HCT. The investigated variables included: vaccination of the HCT recipients and their donors prior to HCT, chronic graft versus host disease (cGVHD) and the timing of post-HCT vaccination, and B- and T-cell subtype status. Forty-two patients were immunized with three or more doses of recombinant hepatitis B surface antigen (rHBsAg) administered according to the individualized schedule of 0-1-2-6-(12) months. After vaccination, seroconversion was achieved in the whole group. The vaccines were categorized according to the antibody (Ab) titers as weak (WRs; 28.7%), good (GRs; 38%) or very good responders (VGRs; 3.3%). In multivariate logistic regression, severe cGVHD (OR= 15.5), and preceding donor immunization (OR= 0.13) were independent predictors of a weak response to vaccination. A prior belonging to the WR group impaired the durability of protection (OR= 0.17) at a median follow-up of 11.5 years. Patients with severe cGVHD showed a trend toward lower median Ab titers, although they required a higher rate of booster vaccine doses. All VGRs had CD4+ cells > 0.2 x 10⁶/L. There was a lower mean rate of CD4+IL2+ lymphocytes in WRs. Vaccination demonstrated the immunomodulatory effect on B-cell and T-cell subsets and a Th1/Th2 cytokine profile, while shifts depended on a history of severe cGVHD and the type of vaccine responder. To conclude, vaccination of HCT donors against HBV allows a better response to vaccination in the respective HCT recipients. Double doses of rHBsAg should be considered in patients with cGVHD and in those not immunized before HCT. A dedicated intensified vaccination schedule should be administered to WRs.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

Respiratory Viruses Cause Late Morbidity in Recipients of Hematopoietic Stem Cell Transplantation

Common respiratory viral infections (CRVIs) frequently complicate hematopoietic stem cell transplantation (HSCT). We conducted a retrospective, single-center, observational cohort study to determine the incidence of CRVI in patients who received an allogeneic (allo) or autologous (auto) HSCT at the Royal Adelaide Hospital between 2009 and 2017. The median follow-up was 8.9 and 4.5 years for auto- and allo-HSCT recipients, respectively. There were 149 CRVI episodes in 74 patients, with rhinovirus being the most commonly isolated virus (n = 81, 47%). The majority of CRVIs (113/149, 75.8%) occurred more than 100 days post-HSCT and 67% were diagnosed in the outpatient setting. There was evidence of lower respiratory tract infection (LRTI) in 45.6% (68/149) of CRVIs. On multivariate logistic regression analysis, coviral infections and cytomegalovirus viremia were independent risk factors for progression of CRVI to LRTI. Ten (6.7%) CRVI episodes resulted in admission to intensive care for ventilatory support and 8 (5.4%) patients died within 30 days of CRVI diagnosis. In our study, 10.4% of HSCT recipients experienced a CRVI post-transplant, primarily causing late morbidity and potentially mortality. Prevention with strict infection control practices, vaccination, and patient education is essential.

B Cell Reconstitution and Influencing Factors After Hematopoietic Stem Cell Transplantation in Children

B cell reconstitution after hematopoietic stem cell transplantation (HSCT) is variable and influenced by different patient, donor, and treatment related factors. In this review we describe B cell reconstitution after pediatric allogeneic HST, including the kinetics of reconstitution of the different B cell subsets and the development of the B cell repertoire, and discuss the influencing factors. Observational studies show important roles for stem cell source, conditioning regimen, and graft vs. host disease in B cell reconstitution. In addition, B cell recovery can play an important role in post-transplant infections and vaccine responses to encapsulated bacteria, such as pneumococcus. A substantial number of patients experience impaired B cell function and/or dependency on Ig substitution after allogeneic HSCT. The underlying mechanisms are largely unresolved. The integrated aspects of B cell recovery after HSCT, especially BCR repertoire reconstitution, are awaiting further investigation using modern techniques in order to gain more insight into B cell reconstitution and to develop strategies to improve humoral immunity after allogeneic HSCT.