Safety and efficacy of early vaccination with live attenuated measles vaccine for hematopoietic stem cell transplant recipients and solid organ transplant recipients

[Vaccination of allogeneic haematopoietic stem cell transplant recipients: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

During immune reconstitution following allogeneic haematopoietic stem cell transplantation (allo-HSCT), (re)vaccination of allo-HSCT recipients is recommended. Herein, we propose an update of practical recommendations regarding vaccination of allo-HSCT recipients. These recommendations, based on data from the literature, national and international guidelines and the consensus of the participants when no formally proven data are available, were elaborated during the workshop of practice harmonization organized by the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) in Lille in September 2022.

Vaccination Recommendations in Solid Organ Transplant Adult Candidates and Recipients

Prevention of infections is crucial in solid organ transplant (SOT) candidates and recipients. These patients are exposed to an increased infectious risk due to previous organ insufficiency and to pharmacologic immunosuppression. Besides infectious-related morbidity and mortality, this vulnerable group of patients is also exposed to the risk of acute decompensation and organ rejection or failure in the pre- and post-transplant period, respectively, since antimicrobial treatments are less effective than in the immunocompetent patients. Vaccination represents a major preventive measure against specific infectious risks in this population but as responses to vaccines are reduced, especially in the early post-transplant period or after treatment for rejection, an optimal vaccination status should be obtained prior to transplantation whenever possible. This review reports the currently available data on the indications and protocols of vaccination in SOT adult candidates and recipients.

Real-world challenges in eligibility for MMR vaccination two years after autologous and allogeneic HSCT

Measles outbreaks have raised concerns of fatal infections in immunocompromised patients. Canadian guidelines advise administration of live vaccines, such as measles, mumps, and rubella (MMR), two yearsafter hematopoietic stem cell transplant (HSCT) yet studies have not assessed eligibility based on medication contraindications. We retrospectively reviewed the charts of 72 autologous (auto-HSCT) and 68 allogeneic (allo-HSCT) recipients at the Windsor Regional Cancer Center to determine MMR reactivity and eligibility based on administration of contraindicated medications two years post-HSCT. Reactivity to measles, mumps, and rubella in auto-HSCT recipients was 49.1 %, 28.8 %, and 52.3 %, respectively, and in allo-HSCT recipients was 75.6 %, 57.8 %, and 64.4 %, respectively. Immunity to all three components was significantly different between transplant types (p = 0.0002). Nearly 80 % of auto-HSCT patients were on a contraindicated medication at two years compared to 45 % of allo-HSCT recipients. Auto-HSCT recipients require MMR revaccination, but it is contraindicated in a large proportion of patients.

Spotting a potential threat: Measles among pediatric solid organ transplantation recipients

BACKGROUND

Low-vaccination rates worldwide have led to the re-emergence of vaccine-preventable infections, including measles. Immunocompromised patients, including pediatric solid organ transplant (SOT) recipients, are at risk for measles because of suboptimal vaccination, reduced or waning vaccine immunity, lifelong immunosuppression, and global re-emergence of measles.

OBJECTIVES

To review published cases of measles in pediatric SOT recipients to heighten awareness of its clinical manifestations, summarize diagnostic and treatment strategies, and identify opportunities to optimize prevention.

METHODS

We conducted a literature review of published natural measles infections in SOT recipients ≤21 years of age, summarizing management and outcomes. We describe measles epidemiology, recommended diagnostics, treatment, and highlight prevention strategies.

RESULTS

There are seven published reports of measles infection in 12 pediatric SOT recipients, the majority of whom were unvaccinated or incompletely vaccinated. Subjects had atypical or severe clinical presentations, including lack of rash and complications, most frequently with encephalitis and pneumonitis, resulting in 33% mortality. Updated recommendations on testing and vaccination are provided. Treatment options beyond supportive care and vitamin A are limited, with no approved antivirals.

CONCLUSION

While measles is infrequently reported in pediatric SOT recipients, morbidity and mortality remain significant. A high index of suspicion is warranted in susceptible SOT recipients with clinically compatible illness or exposure. Providers must recognize this risk, educate families, and be aware of both classic and atypical presentations of measles to rapidly identify, isolate, and diagnose measles in pediatric SOT recipients. Continued efforts to optimize measles vaccination both pre- and post-SOT are warranted.

Influence of Acute and Chronic Graft-Versus-Host Disease on Persistence of Antibodies against Measles, Mumps, Rubella and Varicella in the First Year after Autologous or Allogeneic Hematopoietic Stem Cell Transplantation

Patients after hematopoietic stem cell transplantation (HSCT) are vulnerable to infections due to severe immunosuppression. Live-attenuated vaccines are contraindicated for two years after HSCT. The aim of this study was to assess the persistence of antibodies against measles, mumps, rubella and varicella in the first year after HSCT. Forty patients undergoing autologous (n = 12) or allogeneic (n = 28) HSCT were included in this study. Specific IgG antibodies to measles, mumps, rubella and varicella virus in serum samples were assessed by the LIAISON XL, a fully automated chemiluminescence analyzer, at seven different time points starting one week before HSCT and up to 12 months after HSCT. At baseline, before HSCT, most patients showed antibodies against measles (100%), mumps (80%), rubella (97.5%) and varicella (92.5%). Although titers declined over time, most patients retained antibodies against measles (92.5%), mumps (62.5%), rubella (87.5%) and varicella (85%) up to 12 months after HSCT. There was no significant difference between patients with and without GvHD concerning persistence of antibody titers. Significantly higher varicella titers were detected in autologous patients compared to patients with chronic GvHD. Considering that live-attenuated vaccines should not be administered during the first year after HSCT, the persistence of antibodies against these diseases is relevant.

Prevention of infections including vaccination strategies in multiple myeloma

Infections are a major cause of morbidity and mortality in multiple myeloma. The increased risk for bacterial and viral infections results mainly from the disease-inherent and treatment-induced immunosuppression. Additional risk factors are older age with immune senescence, T cell depletion, polymorbidity, and male gender. Hence, every effort should be taken to reduce the risk for infections by identifying patients at higher risk for these complications and by implementing prophylactic measures, including chemoprophylaxis and immunization against various relevant pathogens. Here, we review the available evidence and provide recommendations for medical prophylaxis and vaccination in clinical practice.

Vaccination for the Prevention of Infection among Immunocompromised Patients: A Concise Review of Recent Systematic Reviews

Vaccination is crucial for avoiding infection-associated morbidity and mortality among immunocompromised patients. However, immunocompromised patients respond less well to vaccinations compared to healthy people, and little is known about the relative efficacy of various vaccines among different immunocompromised states. A total of 54 systematic reviews (22 COVID-19; 32 non-COVID-19) published within the last 5 years in Pubmed® were reviewed. They demonstrated similar patterns within three seroconversion response categories: good (about >60% when compared to healthy controls), intermediate (~40−60%), and poor (about <40%). Good vaccine responses would be expected for patients with chronic kidney disease, human immunodeficiency virus infection (normal CD4 counts), immune-mediated inflammatory diseases, post-splenectomy states, and solid tumors. Intermediate vaccine responses would be expected for patients with anti-cytotoxic T-lymphocyte antigen-4 therapy, hematologic cancer, and human immunodeficiency virus infection (low CD4 counts). Poor vaccine responses would be expected for patients with B-cell-depleting agents (e.g., anti-CD20 therapy), hematopoietic stem-cell transplant, solid organ transplant, and liver cirrhosis. For all vaccine response categories, vaccination should be timed when patients are least immunosuppressed. For the intermediate and poor vaccine response categories, high-dose vaccine, revaccination when patients are less immunosuppressed, checking for seroconversion, additional booster doses, and long-acting monoclonal antibodies may be considered, supplemented by shielding measures.