Immunologic response of mRNA SARS-CoV-2 vaccination in adolescent kidney transplant recipients

Serologic Responses to COVID-19 Vaccination in Pediatric Kidney Transplant Recipients

Background

There are limited data describing the immune responses to COVID-19 vaccination in pediatric kidney transplant recipients, and expanding upon this information could help inform vaccination strategies in this unique population.

Methods

We performed a prospective, observational, single-center cohort study using remnant blood samples of pediatric kidney transplant recipients from routine clinic visits to examine longitudinal serological responses after COVID-19 vaccination. We enrolled 61 pediatric kidney transplant recipients who had at least 1 sample available for analysis. Sera or plasma were analyzed for ancestral SARS-CoV-2 and Omicron (B.1.1.529; BA.1) spike IgG and nucleocapsid IgG using a Meso Scale Discovery platform.

Results

One month after a 3-dose COVID-19 vaccination series, the IgG geometric mean titer to the SARS-CoV-2 ancestral spike was 684 binding antibody units/mL (95% confidence interval, 269-1739), but titers waned by 4-6 mo. A fourth dose of the COVID-19 vaccine boosted IgG geometric mean titer to 1606 binding antibody units/mL (95% confidence interval, 868-2972), and titers persisted through 6 mo. IgG titers against Omicron (B.1.1.529; BA.1) were overall lower than ancestral SARS-CoV-2. They were higher in participants with prior infection and were not significantly impacted by receipt of belatacept.

Conclusions

Additional doses of the COVID-19 vaccine bolstered durable serologic responses in pediatric kidney transplant recipients, and this study broadens our understanding of immune responses to COVID-19 vaccinations in this population.

Humoral and cellular response to SARS-CoV-2 mRNA vaccine in paediatric heart transplant recipients

Objective

The aim of this prospective cohort study is to analyse the humoral and cellular vaccine responses in paediatric heart transplant recipients (HTR, n = 12), and compare it with the response in healthy controls (HC, n = 14). All participants were 5-18 years old and vaccinated with mRNA vaccine against SARS-CoV-2 between December 2021 and May 2022.

Methods

The humoral response was measured by quantifying antibody titers against SARS-CoV-2 spike protein (anti-S). The T-lymphocyte phenotype and SARS-CoV2-specific CD4+ and CD8+ T-cell response was studied by multiparametric flow cytometry through peripheral blood mononuclear cells by the quantification of degranulation markers (CD107a) and intracellular cytokines (IFN-γ, TNF-α and IL-2) after in vitro stimulation with SARS-CoV-2 peptides from structural proteins (S, M, N, E) and non-structural viral proteins.

Results

After vaccination, humoral response was found in all HTR, although they showed lower levels of anti-S IgG compared to HC (p = 0.003). However, in terms of cellular response, no significant differences were obtained in the prevalence of responders and magnitude of responses between groups. In addition, anti-S IgG levels directly correlated with a higher SARS-CoV-2 specific T-cell response (rho = 0.43; p = 0.027 and rho = 0.45; p = 0.02 for IFN-γ+ and TNF-α+ production of CD8+ T-cells, respectively). Activated T-cell phenotype in HTR was associated with a lower humoral response to SARS-CoV-2 vaccine.

Conclusion

HTR had humoral response after vaccination, although they showed lower levels of specific anti-S antibodies compared to HC. There were no significant differences in the SARS-CoV2-specific cellular response between the two groups. Obtaining satisfactory data on this type of response could potentially challenge the current vaccine guideline recommendations.

Inter- and intra-individual differences regarding SARS-CoV-2 and influenza vaccination in pediatric kidney transplant recipients: An observational study

In kidney transplant recipients (KTRs), viral infection can lead to antibody and/or T-cell mediated rejection, resulting in kidney transplant dysfunction. Therefore, it is critical to prevent infections. However, KTRs exhibit suboptimal responses to SARS-CoV-2 and/or influenza vaccines, partly due to immunosuppressant therapy. Inter- and intra-individual differences in the biological responses to vaccines may also affect patients' antibody production ability. This study included KTRs who received an messenger RNA SARS-CoV-2 vaccine (3 doses), and an inactivated quadrivalent influenza vaccine (1 or 2 doses). We measured the patients' total antibody titers against SARS-CoV-2 spike antigen, and hemagglutination inhibition (HI) titers against influenza A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Five patients were eligible for this study. Of these 5 KTRs, two produced anti-SARS-CoV-2 spike antibody titers to a seroprotective level, and also produced HI titers against A/H1N1 to a seroprotective level. Another 2 KTRs did not produce seroprotective anti-SARS-CoV-2 antibody titers, but produced seroprotective HI titers against A/H1N1. The remaining KTR produced a seroprotective anti-SARS-CoV-2 antibody titer, but did not produce a seroprotective HI titer against A/H1N1. The 2 KTRs who did not produce seroprotective anti-SARS-CoV-2 antibody titers following vaccination, later developed COVID-19, and this infection increased their titers over the seroprotective level. This study demonstrated that inter- and intra-individual differences in biological responses to vaccines should be considered in pediatric KTRs, in addition to immunosuppressant effects. Personalized regimens, such as augmented or booster doses of vaccines, could potentially improve the vaccination efficacy against SARS-CoV-2 and influenza.

The humoral immune response to the BNT 162B2 vaccine in pediatrics on renal replacement therapy

INTRODUCTION

Since the start of the COVID-19 pandemic, data published on the immunogenicity of the SARS-CoV-2 BNT 162B2 vaccine in pediatric patients receiving renal replacement therapy are scant. Our primary objective is to study this population's humoral immune response to the COVID-19 vaccine.

METHODS

Pediatric kidney transplant recipients (PKTRs) and hemodialysis recipients (HR) at our center who received two doses of the SARS-CoV-2 BNT 162B2 vaccine were included. Transplant and HR who had PCR-positive COVID-19 infections during the study, regardless of their vaccine status, were also included. SARS-CoV-2 anti-spike protein (S1/S2) IgG was measured after the second dose of the vaccine and after any PCR-positive COVID-19 infection as routine clinical practice. Data on demographics, induction, maintenance immunosuppressants, type of transplant, and posttransplant or dialysis duration were included.

RESULTS

Of the 61 patients included, 19 were dialysis recipients who received two doses of vaccine without subsequent infection (HV), and 42 were kidney transplant recipients. All dialysis patients and 33 (78.6%) transplant recipients received two doses of the SARS-CoV-2 BNT 162b2 vaccine. A total of 33.3% (11/33) of the transplant recipients who received vaccination developed COVID-19 infection (KTH) at a median time of 13 days after the second dose of vaccine. Nine transplant patients had pure COVID-19 infection without vaccination (KTI). The seroconversion rate in the HV group was 94.7% (18/19) compared to 50% (11/22) in the kidney transplant vaccine recipients who did not develop subsequent COVID-19 infection (KTV) (p < .001). The median S1/S2 IgG titers for the HV group were 400 AU/mL versus 15 AU/mL in the KTV group (p < .0001). There was no significant difference in the duration of the test from the second dose of the vaccine between HV and KTV (55 vs. 33.5 days, p = .095). The KTH had higher titers than KTV group (370 vs. 15 p < .0001). The median duration of the test after vaccination in the vaccine group and those with hybrid immunity was similar (35 vs. 33.5 days, p = .2).There were no clear predictors for seroconversion in the PKTRs. Natural infection alone was as good as the vaccine in eliciting humoral immune response.

CONCLUSION

The humoral immune response to two doses of the SARS-CoV-2 BNT 162B2 vaccine in PKTRs without subsequent COVID-19 infection is suboptimal compared to that in hemodialysis recipients and in PKTRs with hybrid immunity from both infection and vaccination.

Humoral and Cellular Immunogenicity of 3 Doses of BNT162b2 in Children With Kidney Diseases

Introduction

Patients with severe kidney diseases are at risk of complications from COVID-19; however, little is known about the effectiveness of COVID-19 vaccines in children and adolescents with kidney diseases.

Methods

We investigated the immunogenicity and safety of an accelerated 3-dose primary series of COVID-19 vaccination among 59 pediatric patients with chronic kidney disease (CKD) (mean age 12.9 years; 30 male) with or without immunosuppression, dialysis, or kidney transplant. Dosage was 0.1 ml BNT162b2 to those aged 5 to 11 years, and 0.3 ml BNT162b2 to those aged 11 to 18 years.

Results

Three doses of either vaccine type elicited significant antibody responses that included spike receptor-binding domain (S-RBD) IgG (90.5%-93.8% seropositive) and surrogate virus neutralization (geometric mean sVNT% level, 78.6%-79.3%). There were notable T cell responses. Weaker neutralization responses were observed among those on immunosuppression, especially those receiving higher number of immunosuppressants or on mycophenolate mofetil. Neutralization was reduced against Omicron BA.1 compared to wild type (WT, i.e., ancestral) (post-dose 3 sVNT% level; 82.7% vs. 27.4%; P < 0.0001). However, the T cell response against Omicron BA.1 was preserved, which likely confers protection against severe COVID-19. Infected patients exhibited hybrid immunity after vaccination, as evidenced by the higher Omicron BA.1 neutralization response among these infected patients who received 2 doses compared with those who were uninfected. Generally mild or moderate adverse reactions following vaccines were reported.

Conclusion

An accelerated 3-dose primary series with BNT162b2 is immunogenic and safe in young children and adolescents with kidney diseases.

Increasing SARS-CoV-2 seroprevalence among UK pediatric patients on dialysis and kidney transplantation between January 2020 and August 2021

BACKGROUND

Coronavirus disease 2019 (COVID-19) was officially declared a pandemic by the World Health Organisation (WHO) on 11 March 2020, as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread rapidly across the world. We investigated the seroprevalence of anti-SARS-CoV-2 antibodies in pediatric patients on dialysis or kidney transplantation in the UK.

METHODS

Excess sera samples were obtained prospectively during outpatient visits or haemodialysis sessions and analysed using a custom immunoassay calibrated with population age-matched healthy controls. Two large pediatric centres contributed samples.

RESULTS

In total, 520 sera from 145 patients (16 peritoneal dialysis, 16 haemodialysis, 113 transplantation) were analysed cross-sectionally from January 2020 until August 2021. No anti-SARS-CoV-2 antibody positive samples were detected in 2020 when lockdown and enhanced social distancing measures were enacted. Thereafter, the proportion of positive samples increased from 5% (January 2021) to 32% (August 2021) following the emergence of the Alpha variant. Taking all patients, 32/145 (22%) were seropositive, including 8/32 (25%) with prior laboratory-confirmed SARS-CoV-2 infection and 12/32 (38%) post-vaccination (one of whom was also infected after vaccination). The remaining 13 (41%) seropositive patients had no known stimulus, representing subclinical cases. Antibody binding signals were comparable across patient ages and dialysis versus transplantation and highest against full-length spike protein versus spike subunit-1 and nucleocapsid protein.

CONCLUSIONS

Anti-SARS-CoV-2 seroprevalence was low in 2020 and increased in early 2021. Serological surveillance complements nucleic acid detection and antigen testing to build a greater picture of the epidemiology of COVID-19 and is therefore important to guide public health responses. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

Safety and Immunogenicity of SARS-CoV-2 Recombinant Spike Protein Vaccine in Children and Adolescents in India: A Phase 2-3 Randomized Clinical Trial

Importance

The recombinant COVID-19 vaccine NVX-CoV2373 has demonstrated efficacy of approximately 90% in adults; however, its safety and efficacy in children is unknown.

Objective

To assess the noninferiority of SII-NVX-CoV2373 in children and adolescents compared to adults and to evaluate its safety in comparison with placebo.

Design, Setting, and Participants

This phase 2-3 observer-blind randomized clinical trial was conducted in 2 cohorts, children (aged 2 to 11 years) and adolescents (aged 12 to 17 years) between August 2021 and August 2022. Participants were randomized 3:1 to SII-NVX-CoV2373 or placebo and monitored for 179 days. The participants, study team, and laboratory staff were blinded. This was a multicenter study conducted across 10 tertiary care hospitals in India. Exclusion criteria included previous COVID-19 infection or vaccination, immunocompromised condition, and immunosuppressive medications.

Interventions

Two doses of 0.5-mL SII-NVX-CoV2373 or placebo were administered intramuscularly on days 1 and 22.

Main Outcomes and Measures

Primary outcomes were geometric mean titer ratio of both anti-spike (anti-S) IgG and neutralizing antibodies (NAbs) between both pediatric age groups to that of adults on day 36. Noninferiority was concluded if the lower bound of 95% CI of this ratio was greater than 0.67 for each age group. Both the antibodies were assessed for the index strain and for selected variants at various time points. Solicited adverse events (AEs) were recorded for 7 days after each vaccination, unsolicited AEs were recorded for 35 days, and serious AEs and AEs of special interest were recorded for 179 days.

Results

A total of 460 children in each age cohort were randomized to receive vaccine or placebo. The mean (SD) age was 6.7 (2.7) years in the child cohort and 14.3 (1.6) years in the adolescent cohort; 231 participants (50.2%) in the child cohort and 218 in the adolescent cohort (47.4%) were female. Both anti-S IgG and NAb titers were markedly higher in the SII-NVX-CoV2373 group than in the placebo group on both day 36 and day 180. The geometric mean titer ratios compared to those in adults were 1.20 (95% CI, 1.08-1.34) and 1.52 (95% CI, 1.38-1.67) for anti-S IgG in adolescents and children, respectively; while for NAbs, they were 1.33 (95% CI, 1.17-1.50) and 1.93 (95% CI, 1.70-2.18) in adolescents and children, respectively, indicating noninferiority. SII-NVX-CoV2373 also showed immune responses against variants studied. Injection site reactions, fever, headache, malaise, and fatigue were common solicited AEs. There were no AEs of special interest and no causally related serious AEs.

Conclusions and Relevance

SII-NVX-CoV2373 was safe and well tolerated in children and adolescents in this study. The vaccine was highly immunogenic and may be used in pediatric vaccination against COVID-19.

Trial Registration

Clinical Trials Registry of India Identifier: CTRI/2021/02/031554.

Humoral and cellular response to the COVID-19 vaccine in immunocompromised children

BACKGROUND

A suboptimal response to the 2-dose COVID-19 vaccine series in the immunocompromised population prompted recommendations for a 3rd primary dose. We aimed to determine the humoral and cellular immune response to the 3rd COVID-19 vaccine in immunocompromised children.

METHODS

Prospective cohort study of immunocompromised participants, 5-21 years old, who received 2 prior doses of an mRNA COVID-19 vaccine. Humoral and CD4/CD8 T-cell responses were measured to SARS-CoV-2 spike antigens prior to receiving the 3rd vaccine dose and 3-4 weeks after the 3rd dose was given.

RESULTS

Of the 37 participants, approximately half were solid organ transplant recipients. The majority (86.5%) had a detectable humoral response after the 2nd and 3rd vaccine doses, with a significant increase in antibody levels after the 3rd dose. Positive T-cell responses increased from being present in 86.5% to 100% of the cohort after the 3rd dose.

CONCLUSIONS

Most immunocompromised children mount a humoral and cellular immune response to the 2-dose COVID-19 vaccine series, which is significantly augmented after receiving the 3rd vaccine dose. This supports the utility of the 3rd vaccine dose and the rationale for ongoing emphasis for vaccination against COVID-19 in this population.

IMPACT

Most immunocompromised children mount a humoral and cellular immune response to the 2-dose COVID-19 vaccine series, which is significantly augmented after receiving the 3rd vaccine dose. This is the first prospective cohort study to analyze both the humoral and T-cell immune response to the 3rd COVID-19 primary vaccine dose in children who are immunocompromised. The results of this study support the utility of the 3rd vaccine dose and the rationale for ongoing emphasis for vaccination against COVID-19 in the immunosuppressed pediatric population.

Coronavirus disease 2019 vaccine in pediatric post-kidney transplantation

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the resulting disease, coronavirus disease 2019 (COVID-19), have spread to millions of persons worldwide. Many vaccines have been developed; however, their efficacy in pediatric solid organ transplant recipients is yet to be determined.

METHODS

This is a prospective observational, non-interventional single-center study on the safety and efficacy of a COVID-19 vaccine (BNT162b2) in pediatric kidney transplant recipients. The primary aim of this study was to evaluate immunogenicity according to SARS-CoV-2-specific neutralizing antibody titer after two vaccine doses. The secondary aims were to investigate the safety of the vaccines, solicited local and systemic adverse reactions, incidence of COVID-19 post-vaccination, and effects on transplant graft function. Baseline investigations were conducted on pediatric renal transplant recipients, and recruited participants were advised to have the Comirnaty® mRNA vaccine according to protocol.

RESULTS

A total of 48 patients (male, n = 31, 64.6%; female, n = 17, 35.4%), median age 14 [12-16] years were included, and all received two doses of the vaccine. The vaccine had a favorable safety and side-effect profile. The S-antibody titer of all patients ranged between .4 and 2,500 U/ml and was > 50 U/ml in 89% of the patients. No difference in the measured antibody immune response was noted between infected and uninfected children. No major side effects were reported.

CONCLUSION

The vaccine had a favorable safety profile in 12- to 15-year-old kidney transplant recipients, producing a greater measured antibody response than that in older transplant recipients.

Optimizing COVID-19 Vaccination Strategy in Pediatric Kidney Transplant Recipients: Humoral and Cellular Response to SARS-CoV-2 mRNA Vaccination

In this retrospective cohort study, we analyze the early humoral and cellular response in 64 adolescents KTx recipients, after two or three doses of mRNA vaccine BNT162b2 against different variants of COVID-19. After 2 doses, 77.8% % of children with no history of infection had a positive humoral response with a median anti-S IgG level of 1107 (IQR, 593-2,658) BAU/mL. All the patients with a history of infection responded with a higher median IgG level (3,265 (IQR, 1,492-8,178) BAU/mL). In non-responders after 2 doses, 75% responded after a third dose with a median Ab titer at 355 (IQR, 140-3,865 BAU/mL). Neutralizing activity was significantly lower against the delta and the omicron variants compared to the wild-type strain and did not improve after a 3rd dose, while infection did provide higher levels of neutralizations against the variants. T cell specific response correlated with humoral response and no patient displayed a cellular response without a humoral response. Adolescent KTx recipients exhibit a high seroconversion rate after only two doses. A third injection, induces a response in the majority of the non-responders patients but did not counterbalance the strong decrease in neutralizing antibody activities against variants highlighting the need for boosters with specific vaccines.

Serologic response to COVID-19 infection or vaccination in pediatric kidney transplant recipients compared to healthy children

BACKGROUND

Differences in serologic response to COVID-19 infection or vaccination were reported in adult kidney transplant recipients (KTR) compared to non-immunocompromised patients. This study aims to compare the serologic response of naturally infected or vaccinated pediatric KTR to that of controls.

METHODS

Thirty-eight KTR and 42 healthy children were included; aged ≤18 years, with a previously confirmed COVID-19 infection or post COVID-19 vaccination. Serological response was measured by anti-spike protein IgG antibody titers. Response post third vaccine was additionally assessed in KTR.

RESULTS

Fourteen children in each group had previously confirmed infection. KTR were significantly older and developed a 2-fold higher antibody titer post-infection compared to controls [median (interquartile range [IQR]) age: 14.9 (7.8, 17.5) vs. 6.3 (4.5, 11.5) years, p = 0.02; median (IQR) titer: 1695 (982, 3520) vs. 716 (368, 976) AU/mL, p = 0.03]. Twenty-four KTR and 28 controls were vaccinated. Antibody titer was lower in KTR than in controls [median (IQR): 803 (206, 1744) vs. 8023 (3032, 30,052) AU/mL, p < 0.001]. Fourteen KTR received third vaccine. Antibody titer post booster in KTR reached similar levels to those of controls post two doses [median (IQR) 5923 (2295, 12,278) vs. 8023 (3034, 30,052) AU/mL, p = 0.37] and to KTR post natural infection [5282 AU/mL (2583, 13,257) p = 0.8].

CONCLUSION

Serologic response to COVID-19 infection was significantly higher in KTR than in controls. Antibody level in KTR was higher in response to infection vs. vaccination, contrary to reports in the general population. Response to vaccination in KTR reached levels comparable to controls only after third vaccine.

A Scoping Review of the Impact of COVID-19 on Kidney Transplant Patients in the United States

SARS-CoV-2, responsible for the COVID-19 pandemic, is a highly infectious virus that quickly became and continues to be a public health emergency, given the severe international implications. Immunocompromised patients, such as those undergoing kidney transplantation, are at an increased risk for severe illness from COVID-19 and require hospitalization for more aggressive treatment to ensure survival. COVID-19 has been infecting kidney transplant recipients (KTRs), affecting their treatment protocols, and threatening their survival. The objective of this scoping review was to summarize the published literature regarding the impact of COVID-19 on KTRs in the United States in terms of prevention, various treatment protocols, COVID-19 vaccination, and risk factors. The databases such as PubMed, MEDLINE/Ebsco, and Embase were used to search for peer-reviewed literature. The search was restricted to articles that were published on KTRs in the United States from January 1, 2019, to March 2022. The initial search yielded 1,023 articles after removing duplicates, leading to a final selection of 16 articles after screening with inclusion and exclusion criteria. Four domains emerged from the review: (1) impacts of COVID-19 on performing kidney transplants, (2) impacts of COVID-19 vaccinations on KTRs, (3) outcomes of treatment regiments for KTRs with COVID-19, and (4) risk factors associated with an increased mortality rate of COVID-19 in KTRs. Waitlisted patients for kidney transplants had a higher risk of mortality compared to nontransplant patients. COVID-19 vaccinations in KTRs are found to be safe, and the immune response can be improved by placing patients on a low dose of mycophenolate before vaccination. Withdrawal of immunosuppressants showed a mortality rate of 20% without increasing the rate of acute kidney injury (AKI). There is evidence to support that kidney transplantation with the accompanying immunosuppressant regimen can provide KTRs with better COVID-19 infection outcomes compared to waitlisted patients. Hospitalization, graft dysfunction, AKI, and respiratory failure were the most common risk factors that increased the risk of mortality in COVID-19-positive KTRs. Withdrawing KTRs from immunosuppressive drugs increased the mortality rate. Further studies are needed to investigate the effects of specific drugs and dosages on the severity and mortality rate of COVID-19 in KTRs.

Immunologic response to SARS-CoV-2 mRNA vaccination in pediatric kidney transplant recipients

BACKGROUND

COVID-19 disease in kidney transplant (KT) recipients is associated with increased morbidity, mortality, and hospitalization rates. Unfortunately, KT recipients also have a reduced response to SARS-CoV-2 immunization. The primary aim of this study was to assess immunologic response to SARS-CoV-2 mRNA vaccines in pediatric kidney transplant recipients 12-18 years of age. Secondary aims were to assess response rates following a third immunization and determine factors that influence immunization response.

METHODS

Pediatric KT recipients in a single tertiary center received SARS-CoV-2 mRNA vaccination as per local protocol. SARS-CoV-2 immunoglobulin (IgG) was measured following second and/or third vaccination. Demographics including patient factors (age, gender, and underlying disease), transplant factors (time and type of transplant), and immunosuppression (induction, maintenance, and immunomodulatory therapies such as IVIG) were collected from the medical records.

RESULTS

Of 20 participants, 10 (50%) responded following a two-dose vaccine schedule, which increased to 15 (75%) after three doses. Maintenance immunosuppression affected immunologic response, with azathioprine demonstrating a higher rate of response to vaccine compared to mycophenolate (100% vs. 38%, p = 0.04). Increasing prednisolone dose had a negative impact on immunologic response (0.01 mg/kg/day increase: OR 1.60 95% CI 1.01 to 2.57). Tacrolimus dose and trough levels, age, time post-transplant, underlying disease, and other immunosuppression did not impact immunologic response.

CONCLUSIONS

Pediatric KT recipients had similar response rates following SARS-CoV-2 immunization as adult KT recipients. Immunologic response improved following a third immunization. Choice of antimetabolite and prednisolone dosing influenced the rate of response. A higher resolution version of the Graphical abstract is available as Supplementary Information.

Antibody response to 2- and 3-dose SARS-CoV-2 mRNA vaccination in pediatric and adolescent kidney transplant recipients

BACKGROUND

Additional "booster" doses of mRNA SARS-CoV-2 vaccines have become standard of care for immunosuppressed patients, including kidney transplant recipients (KTR). While these additional doses have been shown to be efficacious in the adult KTR population, there is paucity of data for pediatric and adolescent KTR.

METHODS

We conducted a retrospective single-center observational study to determine the proportion of pediatric and adolescent KTR who seroconverted following two- and three-dose regimens of an mRNA SARS-CoV-2 vaccine series.

RESULTS

Forty-three pediatric and adolescent KTR at our center received at least two doses of an mRNA SARS-CoV-2 vaccine. Seroconversion was noted in 56% of those who received a 2-dose series and increased to 85% in those who received a third dose. In the 16 patients who did not seroconvert after a two-dose series, 12 (75%) seroconverted following the third dose. No serious adverse effects of immunization were noted.

CONCLUSIONS

Our results demonstrate that additional SARS-CoV-2 vaccine doses are not only safe and efficacious in pediatric and adolescent KTR, but may be necessary to optimize antibody response. A higher resolution version of the Graphical abstract is available as Supplementary information.

Seroconversion rates in kidney transplant recipients following SARS-CoV-2 vaccination and its association with immunosuppressive agents: a systematic review and meta-analysis

This systematic and meta-analysis aims to evaluate humoral and cellular responses to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine among kidney transplant recipients (KTRs). We conducted a systematic literature search across databases to evaluate seroconversion and cellular response rates in KTRs receiving SARS-CoV-2 vaccines. We extracted studies that assessed seroconversion rates described as the presence of antibody de novo positivity in KTRs following SARS-CoV-2 vaccination published up to January 23rd, 2022. We also performed meta-regression based on immunosuppression therapy used. A total of 44 studies involving 5,892 KTRs were included in this meta-analysis. The overall seroconversion rate following complete dose of vaccines was 39.2% (95% confidence interval [CI], 33.3%-45.3%) and cellular response rate was 41.6% (95% CI, 30.0%-53.6%). Meta-regression revealed that low antibody response rate was significantly associated with the high prevalence of mycophenolate mofetil/mycophenolic acid (p=0.04), belatacept (p=0.02), and anti-CD25 induction therapy uses (p=0.04). Conversely, tacrolimus use was associated with higher antibody response (p=0.01). This meta-analysis suggests that postvaccination seroconversion and cellular response rates in KTRs are still low. And seroconversion rate was correlated with the type of immunosuppressive agent and induction therapy used. Additional doses of the SARS-CoV-2 vaccine for this population using a different type of vaccine are considered.

Humoral Immune Response and Safety of SARS-CoV-2 Vaccination in Pediatric Inflammatory Bowel Disease

INTRODUCTION

Children with inflammatory bowel disease (IBD) may respond differently to COVID-19 immunization as compared with healthy children or adults with IBD. Those younger than 12 years receive a lower vaccine dose than adults. We sought to describe the safety and humoral immune response to COVID-19 vaccine in children with IBD.

METHODS

We recruited children with IBD, ages 5-17 years, who received ≥ 2 doses of the BNT162b2 vaccine by a direct-to-patient outreach and at select sites. Patient demographics, IBD characteristics, medication use, and vaccine adverse events were collected. A subset of participants had quantitative measurement of anti-receptor binding domain IgG antibodies after 2-part immunization.

RESULTS

Our study population included 280 participants. Only 1 participant required an ED visit or hospitalization because of an adverse event. Of 99 participants who underwent anti-receptor binding domain IgG antibody measurement, 98 had a detectable antibody, with a mean antibody level of 43.0 μg/mL (SD 67) and a median of 22 μg/mL (interquartile range 12-38). In adjusted analyses, older age ( P = 0.028) and antitumor necrosis factor monotherapy compared with immunomodulators alone ( P = 0.005) were associated with a decreased antibody level. Antibody response in patients treated with antitumor necrosis factor combination vs monotherapy was numerically lower but not significant.

DISCUSSION

Humoral immune response to COVID-19 immunization in children with IBD was robust, despite a high proportion of this pediatric cohort being treated with immunosuppressive agents. Severe vaccine-related AEs were rare. Overall, these findings provide a high level of reassurance that pediatric patients with IBD respond well and safely to SARS-CoV-2 vaccination.

Immunogenicity of COVID-19 vaccines in solid organ transplant recipients: a systematic review and meta-analysis

BACKGROUND

Solid organ transplant (SOT) recipients are at increased risks of morbidity and mortality associated with COVID-19.

OBJECTIVES

This study aimed to evaluate the immunogenicity of COVID-19 vaccines in SOT recipients.

DATA SOURCES

Electronic databases were searched for eligible reports published from 1 December 2019 to 31 May 2022.

STUDY ELIGIBILITY CRITERIA

We included reports evaluating the humoral immune response (HIR) or cellular immune response rate in SOT recipients after the administration of COVID-19 vaccines.

PARTICIPANTS

SOT recipients who received COVID-19 vaccines.

ASSESSMENT OF RISK OF BIAS

We used the Newcastle-Ottawa scale to assess bias in case-control and cohort studies. For randomised-controlled trials, the Jadad Scale was used.

METHODS

We used a random-effects model to calculate the pooled rates of immune response with 95% CI. We used a risk ratio (RR) with 95% CI for a comparison of immune responses between SOT and healthy controls.

RESULTS

A total of 91 reports involving 11 886 transplant recipients (lung: 655; heart: 539; liver: 1946; and kidney: 8746) and 2125 healthy controls revealed pooled HIR rates after the 1st, 2nd, and 3rd COVID-19 vaccine doses in SOT recipients were 9.5% (95% CI, 7-11.9%), 43.6% (95% CI, 39.3-47.8%) and 55.1% (95% CI, 44.7-65.6%), respectively. For specific organs, the HIR rates were still low after 1st vaccine dose (lung: 4.4%; kidney: 9.4%; heart: 13.2%; liver: 29.5%) and 2nd vaccine dose (lung: 28.4%; kidney: 37.6%; heart: 50.3%; liver: 64.5%).

CONCLUSIONS

A booster vaccination enhances the immunogenicity of COVID-19 vaccines in SOT; however, a significant share of the recipients still has not built a detectable HIR after receiving the 3rd dose. This finding calls for alternative approaches, including the use of monoclonal antibodies. In addition, lung transplant recipients need urgent booster vaccination to improve the immune response.

Humoral and cellular immune response to SARS-CoV-2 mRNA BNT162b2 vaccine in pediatric kidney transplant recipients compared with dialysis patients and healthy children

BACKGROUND

Compared with the general population, the immune response to COVID-19 mRNA vaccines is lower in adult kidney transplant recipients (KTRs). However, data is limited for pediatric KTRs. In this study, we aimed to assess humoral and cellular immune responses to the COVID-19 mRNA vaccine in pediatric KTRs.

METHODS

This multicenter, prospective, case-control study included 63 KTRs (37 male, aged 12-21 years), 19 dialysis patients, and 19 controls. Humoral (anti-SARS-CoV2 IgG, neutralizing Ab (nAb)) and cellular (interferon-gamma release assay (IGRA)) immune responses were assessed at least one month after two doses of BNT162b2 mRNA vaccine.

RESULTS

Among COVID-19 naïve KTRs (n = 46), 76.1% tested positive for anti-SARS-CoV-2 IgG, 54.3% for nAb, and 63% for IGRA. Serum levels of anti-SARS-CoV-2 IgG and nAb activity were significantly lower in KTRs compared to dialysis and control groups (p < 0.05 for all). Seropositivity in KTRs was independently associated with shorter transplant duration (p = 0.005), and higher eGFR (p = 0.007). IGRA titer was significantly lower than dialysis patients (p = 0.009). Twenty (43.4%) KTRs were positive for all immune parameters. Only four of 11 seronegative KTRs were IGRA-positive. COVID-19 recovered KTRs had significantly higher anti-SARS-CoV-2 IgG and nAb activity levels than COVID-19 naïve KTRs (p = 0.018 and p = 0.007, respectively).

CONCLUSIONS

The humoral and cellular immune responses to SARS-CoV-2 mRNA BNT162b2 vaccine are lower in pediatric KTRs compared to dialysis patients. Further prospective studies are required to demonstrate the clinical efficacy of the mRNA vaccine in KTRs. This prospective study was registered in ClinicalTrials.gov (NCT05465863, registered retrospectively at 20.07.2022). A higher resolution version of the Graphical abstract is available as Supplementary information.

Humoral immune response and live-virus neutralization of the SARS-CoV-2 omicron (BA.1) variant after COVID-19 mRNA vaccination in children and young adults with chronic kidney disease

BACKGROUND

Data on humoral immune response to standard COVID-19 vaccination are scarce in adolescent patients and lacking for children below 12 years of age with chronic kidney disease including kidney transplant recipients.

METHODS

We therefore investigated in this retrospective two-center study (DRKS00024668; registered 23.03.2021) the humoral immune response to a standard two-dose mRNA vaccine regimen in 123 CKD patients aged 5-30 years. A live-virus assay was used to assess the serum neutralizing activity against the SARS-CoV-2 omicron (BA.1) variant.

RESULTS

Children aged 5-11 years had a comparable rate and degree of immune response to adolescents despite lower vaccine doses (10 µg vs. 30 µg BNT162b2). Treatment with two (odds ratio 9.24) or three or more (odds ratio 17.07) immunosuppressants was an independent risk factor for nonresponse. The immune response differed significantly among three patient cohorts: 48 of 77 (62.3%) kidney transplant recipients, 21 of 26 (80.8%) patients on immunosuppressive therapy, and 19 of 20 (95.0%) patients with chronic kidney disease without immunosuppressive therapy responded. In the kidney transplant recipients, immunosuppressive regimens comprising mycophenolate mofetil, an eGFR of < 60 mL/min/1.73 m², and female sex were independent risk factors for nonresponse. Two of 18 (11.1%) and 8 of 16 (50.0%) patients with an anti-S1-RBD IgG of 100-1411 and > 1411 BAU/mL, respectively, showed a neutralization activity against the omicron variant.

CONCLUSION

A standard mRNA vaccine regimen in immunosuppressed children and adolescents with kidney disease elicits an attenuated humoral immune response with effective live virus neutralization against the omicron variant in approximately 10% of the patients, underlying the need for omicron-adapted vaccination. A higher resolution version of the Graphical abstract is available as Supplementary information.

Humoral and cellular immune response to mRNA SARS-CoV-2 BNT162b2 vaccine in adolescents with rheumatic diseases

BACKGROUND

Data about safety and efficacy of the mRNA SARS-CoV-2 vaccine in adolescents with rheumatic diseases (RD) is scarce and whether these patients generate a sufficient immune response to the vaccine remains an outstanding question.

OBJECTIVE

To evaluate safety and humoral and cellular immunity of the BNT162b2 vaccine in adolescents 12 to 18 years with RD and immunosuppressive treatment compared with a healthy control group.

METHODS

Adolescents from 12 to 18 years with RD followed at Hospital La Paz in Madrid (n = 40) receiving the BNT162b2 mRNA vaccination were assessed 3 weeks after complete vaccination. Healthy adolescents served as controls (n = 24). Humoral response was measured by IgG antiSpike antibodies, and cellular response by the quantity of IFN-γ and IL-2 present in whole blood stimulated with SARS-CoV-2 Spike and M proteins.

RESULTS

There were no differences in spike-specific humoral or cellular response between groups (median IFN-γ response to S specific protein; 528.80 pg/ml in controls vs. 398.44 in RD patients, p 0.78, and median IL-2 response in controls: 635.68 pg/ml vs. 497.30 in RD patients, p 0.22. The most frequent diagnosis was juvenile idiopathic arthritis (26/40, 65%) followed by Lupus (6/40, 15%). 60% of cases (23/40) received TNF inhibitors and 35% (14/40) methotrexate. 40% of patients (26/64) had previous SARS-CoV-2 infection, 9 in the control group and 17 in the RD patients without differences. Of note, 70% of infections were asymptomatic. A higher IFN-γ production was found in COVID-19 recovered individuals than in naive subjects in both groups (controls: median 859 pg/ml in recovered patients vs. 450 in naïve p 0.017, and RD patients: 850 in recovered vs. 278 in naïve p 0.024). No serious adverse events or flares were reported following vaccination.

CONCLUSIONS

We conclude that standard of care treatment for adolescents with RD including TNF inhibitors and methotrexate did not affect the humoral and the cellular immunity to BNT162b2 mRNA vaccination compared to a healthy control group. The previous contact with SARS-CoV-2 was the most relevant factor in the immune response.

SARS-CoV2 mRNA Vaccine-Specific B-, T- and Humoral Responses in Adolescents After Kidney Transplantation

Protection of adult kidney transplant recipients against SARS-CoV2 was shown to be strongly impaired owing to low reactogenicity of available vaccines. So far, data on vaccination outcomes in adolescents are scarce due to later vaccination approval for this age group. We therefore comprehensively analyzed vaccination-specific humoral-, T- and B-cell responses in kidney transplanted adolescents aged 12–18 years in comparison to healthy controls 6 weeks after standard two-dose BNT162b2 (“Comirnaty”; Pfizer/BioNTech) vaccination. Importantly, 90% (18/20) of transplanted adolescents showed IgG seroconversion with 75% (15/20) developing neutralizing titers. Still, both features were significantly diminished in magnitude compared to controls. Correspondingly, spike-specific B cells were quantitatively reduced and enriched for non-isotype-class-switched IgD⁺27⁺ memory cells in patients. Whereas spike specific CD4⁺ T cell frequencies were similar in both groups, cytokine production and memory differentiation were significantly impaired in transplant recipients. Although our data identify limitations in all arms of vaccine-specific immunity, the majority of our adolescent patients showed robust humoral responses despite antimetabolite-based treatment being associated with poor vaccination outcomes in adults.

Balancing B cell responses to the allograft: implications for vaccination

Balancing enough immunosuppression to prevent allograft rejection and yet maintaining an intact immune system to respond to vaccinations, eliminate invading pathogens or cancer cells is an ongoing challenge to transplant physicians. Antibody mediated allograft rejection remains problematic in kidney transplantation and is the most common cause of graft loss despite current immunosuppressive therapies. The goal of immunosuppressive therapies is to prevent graft rejection; however, they prevent optimal vaccine responses as well. At the center of acute and chronic antibody mediated rejection and vaccine responses is the B lymphocyte. This review will highlight the role of B cells in alloimmune responses including the dependency on T cells for antibody production. We will discuss the need to improve vaccination rates in transplant recipients and present data on B cell populations and SARS-CoV-2 vaccine response rates in pediatric kidney transplant recipients.

Immunogenicity and Reactogenicity of mRNA BNT162b2 COVID-19 Vaccine among Thai Adolescents with Chronic Diseases

Adolescents with underlying diseases are at risk of severe COVID-19. The immune response of BNT162b2 may be poor among immunocompromised adolescents. We aim to describe immunogenicity of mRNA BNT162b2 among adolescents who are immunocompromised or have chronic diseases. We recruited adolescents 12-18 years of age; group A impaired-immunity (post-transplantation, cancer, on immunosuppressive drugs) and group B chronic diseases. A two-dose regimen of BNT162b2 was given. Immunogenicity was determined by surrogate virus neutralization test (sVNT) and IgG against receptor-binding domain (RBD). From August to October 2021, 312 adolescents, with a median age (IQR) of 15 years (13.7-16.5), were enrolled (group A 100, group B 212). The geometric means (GMs) of sVNT (% inhibition) against Delta strain and anti-RBD IgG (BAU/mL) after the 2nd dose among group A were: post-transplantation recipients 52.9 (95% CI 37.7-74.2) and 233.6 (95% CI 79-690.6); adolescents with cancer 62.3 (95% CI 29.2-133.1) and 214.9(95% CI 34.2-1348.6); and adolescents with other immunosuppressive conditions 66.7 (95% CI 52.4-84.8) and 849.8 (95% CI 393.4-1835.8). In group B were: adolescents living with HIV 98 (95% CI 97.3-98.8) and 3240.3 (95% CI 2699-3890.2), and adolescents with other chronic disease 98.6 (95% CI 98.3-98.9) and 3818.5 (95% CI 3490.4-4177.4). At day 90, immunity declined; among impaired-immunity participants were 43.9 (95% CI 30.8-62.4) and 178.7 (95% CI 91.2-350.1) and adolescents with chronic diseases were 90.6 (95% CI 88.4-92.8) and 1037.1 (95% CI 933.3-1152.5). In conclusion, adolescents with impaired immunity had a poor response to 2-doses of BNT162b2, additional dose should be considered. Adolescents with chronic diseases had excellent response but immunity waned after 3 m, booster dose may be required.

Responsiveness to second and third dose of mRNA COVID-19 vaccination in adolescent and young adult heart transplant recipients

BACKGROUND

Third-dose mRNA COVID-19 vaccine is currently recommended in the United States for SOT recipients based in part on data showing diminished immune response, including Ab production, after a two-dose regimen. Data on vaccine response in adolescent and young adult SOT recipients are limited, including no data reported on third-dose responsiveness.

METHODS

Results of serologic testing in a convenience sample of 28 vaccinated adolescent and young adult HT recipients at a single institution were collected from the medical record and summarized.

RESULTS

At a median of 98.5 days (IQR 59-150) after second dose, 17 (61%) had an Ab response. Among 12 who had serology before and after third-dose vaccination, four of seven who were negative prior to third dose became positive at a median of 34 days (IQR 31-39.5) following third dose. No myocarditis, acute rejection, graft dysfunction, graft loss, or deaths were observed.

CONCLUSIONS

These findings support recommendations for the routine administration of three doses of mRNA vaccines in adolescent and young adult HT recipients and show a potential subpopulation in whom the fourth dose should be contemplated.

Immunogenicity and safety of SARS-CoV-2 vaccine with immunosuppressive agents

BACKGROUND

We conducted a prospective study of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccination in children and adolescents who were taking immunosuppressive agents.

METHODS

Two doses of SARS-CoV-2 mRNA vaccine were administered to patients taking immunosuppressive agents. Titers of SARS-CoV-2 spike protein receptor-binding domain antibodies were measured before and after vaccination. Vaccine failure was defined as a postvaccination antibody titer of <0.8 U/mL. Seroconversion rates, factors associated with antibody titers after vaccination, clinical effectiveness against breakthrough infection, and adverse events were evaluated.

RESULTS

A total of 42 patients (median age, 18.1 years) were enrolled. Immunogenicity was measured in 34 patients. The median SARS-CoV-2 spike antibody titer was 329 U/mL (interquartile range [IQR] 50-812 U/mL). Seroconversion (≥0.8 U/mL) was achieved in 29 patients (85%), whereas vaccine failure was diagnosed in five (15%). All patients with vaccine failure were recipients of solid organ transplants (SOTs) and were taking two immunosuppressants. The median antibody titer in SOT recipients (57 U/mL) was significantly lower than that in non-recipients (653 U/mL, P = 0.0002); that of patients taking two immunosuppressive agents (93 U/mL) was lower than that of patients taking one (506 U/mL, P = 0.003). Breakthrough infection occurred in three patients (7%). Adverse events were non-specific, and no flares of primary disease or acute rejection in SOT recipients occurred.

CONCLUSIONS

SARS-CoV-2 mRNA vaccine was immunogenic in children and adolescents taking immunosuppressive agents, although SOT recipients and patients taking two immunosuppressive agents tended to show lower postvaccination antibody titers.