Alternative strategies of posttransplant influenza vaccination in adult solid organ transplant recipients

Immunophenotypic predictors of influenza vaccine immunogenicity in pediatric hematopoietic cell transplant recipients

ABSTRACT

Pediatric hematopoietic cell transplant (HCT) recipients exhibit poor serologic responses to influenza vaccination early after transplant. To facilitate the optimization of influenza vaccination timing, we sought to identify B- and T-cell subpopulations associated with influenza vaccine immunogenicity in this population. We used mass cytometry to phenotype peripheral blood mononuclear cells collected from pediatric HCT recipients enrolled in a multicenter influenza vaccine trial comparing high- and standard-dose formulations over 3 influenza seasons (2016-2019). We fit linear regression models to estimate relationships between immune cell subpopulation numbers before vaccination and prevaccination to postvaccination geometric mean fold rises in antigen-specific (A/H3N2, A/H1N1, and B/Victoria) serum hemagglutination inhibition antibody titers (28-42 days, and ∼6 months after 2 doses). For cell subpopulations identified as predictive of a response to all 3 antigens, we conducted a sensitivity analysis including time after transplant as an additional covariate. Among 156 HCT recipients, we identified 33 distinct immune cell subpopulations; 7 significantly predicted responses to all 3 antigens 28 to 42 days after a 2-dose vaccine series, irrespective of vaccine dose. We also found evidence that baseline absolute numbers of naïve B cells, naïve CD4+ T cells, and circulating T follicular helper cells predicted peak and sustained vaccine-induced titers irrespective of dose or timing of posttransplant vaccine administration. In conclusion, several B- and T-cell subpopulations predicted influenza vaccine immunogenicity in pediatric HCT recipients. This study provides insights into the immune determinants of vaccine responses and may help guide the development of tailored vaccination strategies for this vulnerable population.

A quick algorithmic review on management of viral infectious diseases in pediatric solid organ transplant recipients

Pediatric solid organ transplant is a life-saving procedure for children with end-stage organ failure. Viral infections are a common complication following pediatric solid organ transplantation (SOT), which can lead to increased morbidity and mortality. Pediatric solid organ transplant recipients are at an increased risk of viral infections due to their immunosuppressed state. The most commonly encountered viruses include cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), varicella-zoster virus (VZV), adenoviruses, and BK polyomavirus. Prevention strategies include vaccination prior to transplantation, post-transplant prophylaxis with antiviral agents, and preemptive therapy. Treatment options vary depending on the virus and may include antiviral therapy and sometimes immunosuppression modification. This review provides a Quick Algorithmic overview of prevention and treatment strategies for viral infectious diseases in pediatric solid organ transplant recipient.

Immunogenicity of Inactivated SARS-CoV-2 Vaccine (BBIBP-CorV; Sinopharm) and Short-Term Clinical Outcomes in Vaccinated Solid Organ Transplant Recipients: A Prospective Cohort Study

BackgroundImmunocompromised patients have lower seroconversion rate in response to COVID-19 vaccination. The aim of this study is to evaluate the humoral immune response with short-term clinical outcomes in solid organ transplant recipients vaccinated with SARS-CoV-2 vaccine (BBIBP-CorV; Sinopharm).MethodsThis prospective cohort was conducted from March to December 2021 in Abu Ali Sina hospital, Iran. All transplant recipients, older than 18 years were recruited. The patients received two doses of Sinopharm vaccine 4 weeks apart. Immunogenicity was evaluated through assessment of antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 after the first and second dose of vaccine. The patients were followed up for 6 months after vaccination.ResultsOut of 921 transplant patients, 115 (12.5%) and 239 (26%) had acceptable anti S-RBD immunoglobulin G (IgG) levels after the first and second dose, respectively. Eighty patients (8.68%) got infected with COVID-19 which led to 45 (4.9%) of patients being hospitalized. None of the patients died during follow-up period. Twenty-four (10.9%) liver transplant recipients developed liver enzyme elevation, and increased serum creatinine was observed in 86 (13.5%) kidney transplant patients. Two patients experienced biopsy-proven rejection without any graft loss.ConclusionOur study revealed that humoral response rate of solid organ transplant recipients to Sinopharm vaccine was low.

SARS-CoV-2 Vaccination-Induced Immunogenicity in Heart Transplant Recipients

Among heart transplant (HT) recipients, a reduced immunological response to SARS-CoV-2 vaccination has been reported. We aimed to assess the humoral and T-cell response to SARS-CoV-2 vaccination in HT recipients to understand determinants of immunogenicity. HT recipients were prospectively enrolled from January 2021 until March 2022. Anti-SARS-CoV-2-Spike IgG levels were quantified after two and three doses of a SARS-CoV-2 vaccine (BNT162b2, mRNA1273, or AZD1222). Spike-specific T-cell responses were assessed using flow cytometry. Ninety-one patients were included in the study (69% male, median age 55 years, median time from HT to first vaccination 6.1 years). Seroconversion rates were 34% after two and 63% after three doses. Older patient age (p = 0.003) and shorter time since HT (p = 0.001) were associated with lower antibody concentrations after three vaccinations. There were no associations between vaccine types or immunosuppressive regimens and humoral response, except for prednisolone, which was predictive of a reduced response after two (p = 0.001), but not after three doses (p = 0.434). A T-cell response was observed in 50% after two and in 74% after three doses. Despite three vaccine doses, a large proportion of HT recipients exhibits a reduced immune response. Additional strategies are desirable to improve vaccine immunogenicity in this vulnerable group of patients.

Vaccination in patients with kidney failure: lessons from COVID-19

Infection is the second leading cause of death in patients with chronic kidney disease (CKD). Adequate humoral (antibody) and cellular (T cell-driven) immunity are required to minimize pathogen entry and promote pathogen clearance to enable infection control. Vaccination can generate cellular and humoral immunity against specific pathogens and is used to prevent many life-threatening infectious diseases. However, vaccination efficacy is diminished in patients with CKD. Premature ageing of the immune system and chronic systemic low-grade inflammation are the main causes of immune alteration in these patients. In the case of SARS-CoV-2 infection, COVID-19 can have considerable detrimental effects in patients with CKD, especially in those with kidney failure. COVID-19 prevention through successful vaccination is therefore paramount in this vulnerable population. Although patients receiving dialysis have seroconversion rates comparable to those of patients with normal kidney function, most kidney transplant recipients could not generate humoral immunity after two doses of the COVID-19 vaccine. Importantly, some patients who were not able to produce antibodies still had a detectable vaccine-specific T cell response, which might be sufficient to prevent severe COVID-19. Correlates of protection against SARS-CoV-2 have not been established for patients with kidney failure, but they are urgently needed to enable personalized vaccination regimens.

Analysis of the Specific Immune Response after the Third Dose of mRNA COVID-19 Vaccines in Organ Transplant Recipients: Possible Spike-S1 Reactive IgA Signature in Protection from SARS-CoV-2 Infection

Background: Several studies have indicated that anti-SARS-CoV-2 mRNA vaccinations are less effective in inducing robust immune responses among solid organ transplant recipients (SOTRs) compared with the immunocompetent. The third dose of vaccine in SOTRs showed promising results of immunogenicity, even though clinical studies have suggested that immunocompromised subjects are less likely to build a protective immune response against SARS-CoV-2 resulting in lower vaccine efficacy for the prevention of severe COVID-19. Methods: Serological IgG and IgA were analyzed through CLIA or ELISA, respectively, while Spike-specific T cells were detected by ELISpot assay after the second and third dose of vaccine in 43 SOTRs. Results: The third dose induced an improvement in antibody response against SARS-CoV-2. We also reported a strong correlation between specific humoral and cellular responses after the third dose, even though we did not see significant changes in the magnitude of the SARS-CoV-2-specific T cell response. SOTRs who contracted the SARS-CoV-2 infection after the third dose, despite eliciting a positive IgG response, failed to mount an anti-Spike-S1 IgA response, both after the third dose and after SARS-CoV-2 infection. Conclusions: We can conclude that serum IgA detection can be helpful, along with IgG detection, for the evaluation of vaccine efficacy, principally in fragile subjects at high risk of infection.

Notifiable Infectious Diseases Among Organ Transplant Recipients: A Data-Linked Cohort Study, 2000–2015

Background

Infections, including common communicable infections such as influenza, frequently cause disease after organ transplantation, although the quantitative extent of infection and disease remains uncertain.

Methods

A cohort study was conducted to define the burden of notifiable infectious diseases among all solid organ recipients transplanted in New South Wales, Australia, 2000–2015. Data linkage was used to connect transplant registers to hospital admissions, notifiable diseases, and the death register. Standardized incidence ratios (SIRs) were calculated relative to general population notification rates, accounting for age, sex, and calendar year. Infection-related hospitalizations and deaths were identified.

Results

Among 4858 solid organ recipients followed for 39 183 person-years (PY), there were 792 notifications. Influenza was the most common infection (532 cases; incidence, 1358 [95% CI, 1247–1478] per 100 000 PY), highest within 3 months posttransplant. Next most common was salmonellosis (46 cases; incidence, 117 [95% CI, 87–156] per 100 000 PY), then pertussis (38 cases; incidence, 97 [95% CI, 71–133] per 100 000 PY). Influenza and invasive pneumococcal disease (IPD) showed significant excess cases compared with the general population (influenza SIR, 8.5 [95% CI, 7.8–9.2]; IPD SIR, 9.8 [95% CI, 6.9–13.9]), with high hospitalization rates (47% influenza cases, 68% IPD cases) and some mortality (4 influenza and 1 IPD deaths). By 10 years posttransplant, cumulative incidence of any vaccine-preventable disease was 12%, generally similar by transplanted organ, except higher among lung recipients. Gastrointestinal diseases, tuberculosis, and legionellosis had excess cases among transplant recipients, although there were few sexually transmitted infections and vector-borne diseases.

Conclusions

There is potential to avoid preventable infections among transplant recipients with improved vaccination programs, health education, and pretransplant donor and recipient screening.

Effectiveness and Safety of ANTI SARS-CoV-2 Vaccination in Transplant Patients Treated with Immunosuppressants: A Real-World Pilot Study with a 1-Year Follow-Up

SARS-CoV-2 is a betacoronavirus, which induced a severe pandemic infectious disease around the world. Even if several drugs have been suggested for its treatment, to date, the only strategy to reduce the severity of disease is represented by the use of vaccine. However, the lack of pre-marketing evidence in frail patients suggests the necessity of the real-world study of a vaccine benefit–risk profile. In this study, we evaluated the efficacy and the safety of SARS-CoV-2 vaccination in a cohort of 33 patients treated with an immunosuppressant after solid organ transplant. Both CLIA and LS/MS analysis were used to evaluate the levels of immunoglobulin (Ig)G anti SARS-CoV-2 and the therapeutic drug monitoring of immunosuppressant drugs. We documented that SARS-CoV-2 vaccination induced a dose- and gender-related serological response. In particular, in 63.6% of the enrolled patients, we documented a significant serological response at T2, and after a time related decrease, the booster dose induced a serological response in 72.7% of enrolled patients. In conclusion, the vaccine anti SARS-CoV-2 is immunogenic in patients under immunosuppression, and is not related to the development of ADRs. We also suggest that the booster dose could be used to increase the efficacy of the vaccination, particularly in women.

The type of SARS-CoV-2 vaccine influences serological response in kidney transplant recipients

Vaccination is a promising strategy to control the ongoing pandemic; however, solid organ recipients tend to develop a weaker immune response to vaccination. Anti-spike SARS-CoV-2 antibodies titers were measured 2-4 weeks post-vaccination completion in 131 KT patients without previous infection. Demographic, clinical, and laboratorial parameters were analyzed to identify which factors contributed to seroconversion. Factors that influenced seroconversion, that occurred in 76 patients (58%), were longer time post-transplant, immunosuppression without an antiproliferative drug and vaccination with mRNA vaccines. Patients who received mRNA vaccines had significantly higher rates of seroconversion compared with adenovirus vector vaccines (67% vs 33%, P < .001) and higher anti-spike IgG titers. These findings reinforce the need to discuss the vaccination strategy in this population, including a third dose with a mRNA vaccine.

Acute kidney rejection after anti-SARS-CoV-2 virus-vectored vaccine-case report

COVID-19 infection remains a threat to the health systems of many countries. Potential success in the fight against the COVID-19 pandemic is the vaccination of high-risk groups, including patients with end-stage kidney disease (ESKD) and after solid organ transplantation (SOT). Immunosuppression in kidney transplant recipients can also reduce the immunogenicity of SARS-CoV-2 vaccines (varied by vaccine platform), available data suggest that they are efficacious in approximately 50–70%, compared to non-transplant situations. In this paper, we present a newly developed acute humoral and cellular rejection with acute allograft failure and need of hemodialysis 14 days after administration of the adenovirus vectored SARS-CoV-2 vaccine (AstraZeneca; CHADOx1, AZD1222). This occurred in a patient who previously had an asymptomatic COVID-19 infection. Case reports of acute allograft rejection after vaccination against SARS-CoV-2 can help stratify risk groups of patients who develop hyperimmune reactions. However, it is also possible that those with a previous mild primary COVID-19 infection may also develop acute allograft rejections upon COVID-19 re-infection.

Insufficient response to mRNA SARS-CoV-2 vaccine and high incidence of severe COVID-19 in kidney transplant recipients during pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination may fail to sufficiently protect transplant recipients against coronavirus disease 2019 (COVID-19). We retrospectively evaluated COVID-19 in kidney transplant recipients (n = 226) after BNT162b2 mRNA vaccine administration. The control group consisted of unvaccinated patients (n = 194) during the previous pandemic wave. We measured anti-spike protein immunoglobulin G (IgG) levels and cellular responses, using enzyme-linked immunosorbent spot assay, in a prospective cohort after vaccination (n = 31) and recovery from COVID-19 (n = 19). COVID-19 was diagnosed in 37 (16%) vaccinated and 43 (22%) unvaccinated patients. COVID-19 severity was similar in both groups, with patients exhibiting a comparable need for hospitalization (41% vs. 40%, p = 1.000) and mortality (14% vs. 9%, p = .726). Short posttransplant periods were associated with COVID-19 after vaccination (p < .001). Only 5 (16%) patients achieved positive SARS-CoV-2 IgG after vaccination, and 17 (89%, p < .001) recovered from COVID-19 (median IgG levels, 0.6 vs. 52.5 AU/ml, p < .001). A cellular response following vaccination was present in the majority (n = 22, 71%), with an increase in interleukin 2 secreting T cells (p < .001). Despite detectable T cell immunity after mRNA vaccination, kidney transplant recipients remained at a high risk of severe COVID-19. Humoral responses induced by vaccination were significantly lower than that after COVID-19.

Respiratory viral infections in the immunocompromised

PURPOSE OF REVIEW

During much of the COVID-19 pandemic, respiratory viruses other than SARS-CoV-2 did not infect immunocompromised patients. As mitigation strategies lighten, there has been a rapid resurgence of respiratory viruses globally. This review will summarize our current options for the management of the common respiratory viruses in transplant recipients.

RECENT FINDINGS

Expansion of the availability and increased utilization of multiplex molecular assays have allowed the recognition of the scope of respiratory virus infections in the transplant populations. New antivirals for influenza, respiratory syncytial virus (RSV), parainfluenza virus (PIV) and adenovirus show promise to improve outcomes of these important infections.

SUMMARY

Several new antiviral agents, including combination therapy of oseltamivir as well as baloxavir for influenza, fusion and nucleoprotein inhibitors for RSV, DAS181 for PIV and brincidofovir for adenovirus, hold promise to speed clearance of the virus, improve clinical outcomes and reduce the risk of resistance emergence.

Antibodies, boosters, and optimizing SARS-CoV-2 vaccines for transplantation: A call for more research

Despite emerging data suggesting reduced antibody responses among solid organ transplant recipients following SARS-CoV-2 vaccine, critical unanswered questions remain. The clinical implications of the reduced humoral response need to be assessed through prospective studies. Studies are likewise needed to inform which vaccine dosing strategies result in improved immunity and if such approaches maximize protection against severe infection in the vulnerable transplant population.

Case Report: Severe COVID-19 in a Kidney Transplant Recipient Without Humoral Response to SARS-CoV-2 mRNA Vaccine Series

Supplemental Digital Content is available in the text.

Evaluation of Three anti-SARS-CoV-2 Serologic Immunoassays for Post-Vaccine Response

BACKGROUND

In North America, both mRNA vaccines, Pfizer-BioNTech BNT162b2, and Moderna mRNA-1273, each utilizing a two-dose regimen, have started to be administered to individuals.

METHODS

We evaluated the quantitative serologic antibody response following administration of either a single dose or both doses of an mRNA SARS-CoV-2 vaccine in a cohort of 98 participants (88 healthcare workers [HCW] and 10 solid organ transplant [SOT] recipients). Antibody levels were compared across three immunoassays: Elecsys Anti-SARS-CoV-2 S (Roche Diagnostics), SARS-CoV-2 TrimericS IgG (DiaSorin), and SARS-CoV-2 IgG II Quant (Abbott).

RESULTS

Among HCW, sensitivity ranged from 100% (Roche), 99% (Abbott) and 98% (DiaSorin). The SARS-CoV-2 IgG II Quant and SARS-CoV-2 TrimericS IgG assays showed good agreement with a Pearson correlation coefficient of R = 0.95. Pearson correlation coefficients of R = 0.82 and 0.83 were obtained for Elecsys Anti-SARS-CoV-2 S vs SARS-CoV-2 TrimericS IgG followed by SARS-CoV-2 IgG II Quant vs Elecsys Anti-SARS-CoV-2 S, respectively. Significant differences in antibody levels between HCW and SOT recipients were observed. A decrease in antibody levels from time of vaccine administration to blood draw was evident. Among those with a second dose, an increase in antibody levels with increased time between administration of the first and second dose was observed.

CONCLUSIONS

The absolute values generated from each of the assay platforms are not interchangeable. Antibody levels differed with increased time between vaccine administration and with increased time between administration of the first and second dose. Further, significant differences in antibody levels between HCW and SOT recipients were observed.

Prevention of infection and optimizing vaccination in the solid organ transplant candidate and recipient

PURPOSE OF REVIEW

Infections can result in serious complications in solid organ transplant (SOT) patients. The need to remain up to date on recommendations on screening, vaccinations, and chemoprophylaxis is paramount in the management of SOT patients. The goal of this review is to provide an overview of current recommendations for the prevention of infections and optimization of vaccinations from the pretransplant through posttransplant periods.

RECENT FINDINGS

There is an emphasis on thorough pretransplant evaluation to guide clinicians and pretransplant testing based on epidemiological and endemic risk factors. Additionally, recent studies on vaccine safety and efficacy of newer vaccine formulations in SOT recipients are addressed.

SUMMARY

This review provides insight on updated recommendations for pretransplant screening, new data on vaccine optimization in SOT recipients and posttransplant prophylaxis. Further research is needed in order to improve preventive measures including screening tests, vaccines, and chemoprophylaxis.

Coronavirus disease 2019 vaccination in transplant recipients

PURPOSE OF REVIEW

Coronavirus disease 2019 (COVID-19) vaccination is considered one of the most promising and socioeconomically sustainable strategy to help control the pandemic and several vaccines are currently being distributed in nationwide mass immunization campaigns. Very limited data are available on benefits and risks of COVID-19 vaccination in immunocompromised patients and in particular in solid organ or hematopoietic stem cell transplant recipients as they were excluded from phase III trials. This review summarizes current knowledge, international guidelines and controversies regarding COVID-19 vaccination in these vulnerable populations.

RECENT FINDINGS

Various COVID-19 vaccine platforms showed good efficacy in phase III trials in the immunocompetent and there are data arising on the safety and immunogenicity of these vaccines in the immunocompromised population.

SUMMARY

Transplant recipients could benefit significantly from COVID-19 vaccination, both through active immunization provided they elicit protective vaccine responses, and probably through cocooning by immunization of caregivers and healthcare personnel and thus reducing the risk of SARS-coronavirus-2 exposure. Although awaiting more data on the safety and efficacy of COVID-19 vaccines to inform potential adaptations of vaccine regimens, we strongly recommend prioritizing COVID-19 vaccination of solid and hematopoietic stem cell transplant recipients to decrease COVID-19-related morbidity and mortality.

Preparing for the 2020-2021 influenza season

The COVID-19 pandemic has altered health seeking behaviors and has increased attention to non-pharmaceutical interventions that reduce the risk of transmission of respiratory viruses including SARS-CoV-2 and influenza. While the potential impact of the COVID-19 pandemic on influenza is not fully known, in the Southern hemisphere influenza infection rates appear to be very low. Influenza vaccine efficacy for 2019-2020 season was comparable to prior season and influenza vaccine recommendations for pediatric immunizations remain similar to prior years. Influenza treatments continue to include neuraminidase inhibitors as well as baloxavir for treatment and in some instances prophylaxis.

Poor humoral and T-cell response to two-dose SARS-CoV-2 messenger RNA vaccine BNT162b2 in cardiothoracic transplant recipients

AIMS

Immunocompromised patients have been excluded from studies of SARS-CoV-2 messenger RNA vaccines. The immune response to vaccines against other infectious agents has been shown to be blunted in such patients. We aimed to analyse the humoral and cellular response to prime-boost vaccination with the BNT162b2 vaccine (Pfizer-BioNTech) in cardiothoracic transplant recipients.

METHODS AND RESULTS

A total of 50 transplant patients [1-3 years post heart (42), lung (7), or heart-lung (1) transplant, mean age 55 ± 10 years] and a control group of 50 healthy staff members were included. Blood samples were analysed 21 days after the prime and the boosting dose, respectively, to quantify anti-SARS-CoV-2 spike protein (S) immunoglobulin titres (tested by Abbott, Euroimmun and RocheElecsys Immunoassays, each) and the functional inhibitory capacity of neutralizing antibodies (Genscript). To test for a specific T-cell response, heparinized whole blood was stimulated with SARS-CoV-2 specific peptides, covering domains of the viral spike, nucleocapsid and membrane protein, and the interferon-γ release was measured (QuantiFERON Monitor ELISA, Qiagen). The vast majority of transplant patients (90%) showed neither a detectable humoral nor a T-cell response three weeks after the completed two-dose BNT162b2 vaccination; these results are in sharp contrast to the robust immunogenicity seen in the control group: 98% exhibited seroconversion after the prime dose already, with a further significant increase of IgG titres after the booster dose (average > tenfold increase), a more than 90% inhibition capability of neutralizing antibodies as well as evidence of a T-cell responsiveness.

CONCLUSIONS

The findings of poor immune responses to a two-dose BNT162b2 vaccination in cardiothoracic transplant patients have a significant impact for organ transplant recipients specifically and possibly for immunocompromised patients in general. It urges for a review of future vaccine strategies in these patients.

The future of SARS-CoV-2 vaccines in transplant recipients: To be determined

This editorial discusses the impact of preliminary results of COVID-19 vaccination studies on transplant recipients.

Administration of COVID-19 vaccines in immunocompromised patients

Since the beginning of vaccination programs against COVID-19 in different countries, several populations such as patients with specific immunological conditions have been considered as the priorities for immunization. In this regard, patients with autoimmune diseases or those receiving immunosuppressive agents and anti-cancer therapies, need special attention. However, no confirmed data is presently available regarding COVID-19 vaccines in these populations due to exclusion from the conducted clinical trials. Given the probable suppression or over-activation of the immune system in such patients, reaching a consensus for their vaccination is critical, besides gathering data and conducting trials, which could probably clarify this matter in the future. In this review, besides a brief on the available COVID-19 vaccines, considerations and available knowledge about administering similar vaccines in patients with cancer, hematopoietic stem cell transplantation, solid organ transplantation, multiple sclerosis (MS), inflammatory bowel disease (IBD), and rheumatologic and dermatologic autoimmune disorders are summarized to help in decision making. As discussed, live-attenuated viruses, which should be avoided in these groups, are not employed in the present COVID-19 vaccines. Thus, the main concern regarding efficacy could be met using a potent COVID-19 vaccine. Moreover, the vaccination timing for maximum efficacy could be decided according to the patient’s condition, indicated medications, and the guides provided here. Post-vaccination monitoring is also advised to ensure an adequate immune response. Further studies in this area are urgently warranted.