Clinical Outcomes and Antibody Response in COVID-19-Positive Pediatric Solid Organ Transplant Recipients

COVID-19 disease among children and young adults enrolled in the North American Pediatric Renal Trials and Collaborative Studies registry

BACKGROUND

Coronavirus disease of 2019 (COVID-19) has disproportionately affected adults with kidney disease. Data regarding outcomes among children with kidney disease are limited. The North American Pediatric Renal Trials Collaborative Studies Registry (NAPRTCS) has followed children with chronic kidney disease (CKD) since 1987 at 87 participating centers. This study aimed to evaluate the impact of COVID-19 among participants enrolled in the three arms of the registry: CKD, dialysis, and transplant.

METHODS

This was a retrospective cohort study of COVID-19 among participants in the NAPRTCS CKD, dialysis, and transplant registries from 2020 to 2022. Where appropriate, t-tests, chi-square analyses, and univariate logistic regression were used to evaluate the data.

RESULTS

The cohort included 1505 NAPRTCS participants with recent data entry; 260 (17%) had documented COVID-19. Infections occurred in all three registry arms, namely, 10% (n = 29) in CKD, 11% (n = 67) in dialysis, and 26% (n = 164) in transplant. The majority of participants (75%) were symptomatic. Hospitalizations occurred in 17% (n = 5) of participants with CKD, 27% (n = 18) maintenance dialysis participants, and 26% (n = 43) of transplant participants. Fourteen percent (n = 4) of CKD participants and 10% (n = 17) of transplant participants developed acute kidney injury (AKI), and a total of eight participants (one CKD, seven transplant) required dialysis initiation. Among transplant participants with moderate to severe illness, 40-43% developed AKI and 29-40% required acute dialysis. There were no reported deaths.

CONCLUSIONS

COVID-19 was documented in 17% of active NAPRTCS participants. While there was no documented mortality, the majority of participants were symptomatic, and a quarter required hospitalization.

Impact of Respiratory Viral Infections in Transplant Recipients

Respiratory viral infections (RVIs) are among the leading cause of morbidity and mortality in pediatric hematopoietic stem cell transplant (HCT) and solid organ transplant (SOT) recipients. Transplant recipients remain at high risk for super imposed bacterial and fungal pneumonia, chronic graft dysfunction, and graft failure as a result of RVIs. Recent multicenter retrospective studies and prospective studies utilizing contemporary molecular diagnostic techniques have better delineated the epidemiology and outcomes of RVIs in pediatric transplant recipients and have advanced the development of preventative vaccines and treatment interventions in this population. In this review, we will define the epidemiology and outcomes of RVIs in SOT and HSCT recipients, describe the available assays for diagnosing a suspected RVI, highlight evolving management and vaccination strategies, review the risk of donor derived RVI in SOT recipients, and discuss considerations for delaying transplantation in the presence of an RVI.

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.

Immune Response to SARS-CoV-2 Infections in Children with Secondary Immunodeficiencies

BACKGROUND AND PURPOSE

It is a matter of research, whether children with immunodeficiencies are able to generate an effective immune response to prevent SARS-CoV-2 reinfection. This study aimed to evaluate and compare the seroconversion rates and changes of lymphocyte subsets during COVID-19 in immunocompetent children and those with secondary immunodeficiencies.

METHODS

In 55 children - 28 immunocompromised and 27 immunocompetent - hospitalized with confirmed SARS-CoV-2 infection, the level of IgG antibodies against the Spike protein was determined on two to three occasions. In those children from the study group whose immunosuppressive treatment did not alter during the study (n = 13) and in selected children from the control group (n = 11), flow cytometric evaluation of lymphocyte subsets was performed twice - 2 weeks and 3 months post-infection.

RESULTS

Seroconversion reached 96.3% in both studied groups; however, the immunocompromised cohort achieved lower titers of detectable anti-S antibodies. There was no correlation between seroconversion or titers of antibodies and the total number of lymphocytes or their subsets. In the immunocompetent cohort, we reported a significant decrease in NK cells during the infection. In this group and the entire study population, a positive correlation was noticed between the CD4 + /CD8 + T cell ratio and the severity of COVID-19 pneumonia.

CONCLUSIONS

Children with secondary immunodeficiencies seroconvert in equal percentages but with a significantly lower titer of anti-S antibodies compared to their immunocompetent peers. The lower number of NK cells in the immunocompetent cohort may result from their participation in antiviral immunity, whereas reduced CD4 + /CD8 + T cell ratios among immunocompromised children may be a protective factor against a severe COVID-19.

The impact of COVID-19 on the pediatric solid organ transplant population

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has significantly impacted all aspects of healthcare including solid organ transplantation. In this review, we discuss the specific impact of COVID-19 on the pediatric solid organ transplant population including access to grafts for pediatric transplant candidates as well as COVID-19 disease manifestations in pediatric transplant recipients. We address the current knowledge of prevention and management of COVID-19 in pediatric transplant recipients and provide additional information regarding social distancing, infection prevention and return to school.

Pediatric transplantation during the COVID-19 pandemic

Children infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seem to have a better prognosis than adults. Nevertheless, pediatric solid organ transplantation (SOT) has been significantly affected by the unprecedented coronavirus disease 2019 (COVID-19) pandemic during the pre-, peri-, and post-transplant period. Undoubtedly, immunosuppression constitutes a real challenge for transplant clinicians as increased immunosuppression may prolong disease recovery, while its decrease can contribute to more severe symptoms. To date, most pediatric SOT recipients infected by SARS-CoV-2 experience mild disease with only scarce reports of life-threatening complications. As a consequence, after an initial drop during the early phase of the pandemic, pediatric SOTs are now performed with the same frequency as during the pre-pandemic period. This review summarizes the currently available evidence regarding pediatric SOT during the COVID-19 pandemic.

Return to School and COVID-19 Vaccination for Pediatric Solid Organ Transplant Recipients in the United States: Expert Opinion for 2021-2022

The COVID-19 pandemic continues to generate challenges for pediatric solid organ transplant (SOT) recipients and their families. As rates of COVID-19 fluctuate, new SARS-CoV-2 variants emerge, and adherence to and implementation of mitigation strategies vary from community to community, questions remain about the best and safest practices to prevent COVID-19 in vulnerable patients. Notably, decisions about returning to school remain difficult. We assembled a team of specialists in pediatric infectious diseases, transplant infectious diseases, public health, transplant psychology, and infection prevention and control to re-address concerns about school re-entry, as well as COVID-19 vaccines, for pediatric SOT recipients in the United States in 2021. Based on available literature and guidance from national organizations, we generated expert statements specific to pediatric SOT recipients focused on school attendance in 2021.