Respiratory viral infections in pediatric solid organ and hematopoietic stem cell transplantation

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.

Community-Acquired Respiratory Viruses Post-Lung Transplant

Survival in lung transplant recipients (LTRs) lags behind heart, liver, and kidney transplant, in part due to the direct and indirect effects of infection. LTRs have increased susceptibility to infection due to the combination of a graft continually exposed to the outside world, multiple mechanisms for impaired mucus clearance, and immunosuppression. Community-acquired respiratory viral infections (CARVs) are common in LTRs. Picornaviruses have roughly 40% cumulative incidence followed by respiratory syncytial virus and coronaviruses. Although single-center retrospective and prospective series implicate CARV in rejection and mortality, conclusive evidence for and well-defined mechanistic links to long-term outcome are lacking. Treatment of viral infections can be challenging except for influenza. Future studies are needed to develop better treatments and clarify the links between CARV and long-term outcomes.

Infectious complications in pediatric allogeneic hematopoietic stem cell transplantation recipients-A retrospective clinical and epidemiological cohort study

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is an important therapeutic strategy for several hematologic diseases. In the absence of a matched related donor, allogeneic HSCT has been associated with increased risk of infectious complications. Here, we present the clinical and epidemiological characteristics of early infectious complications in children undergoing HSCT from Southern Brazil.

METHODS

This is a retrospective unicentric cohort study of infections in all children receiving their first HSCT during the period between 2010 and 2017.

RESULTS

Data from 292 patients were analyzed; bone marrow failures (52.7%) comprised most of the baseline diagnosis. Bone marrow (BM) was the stem cell source in 254 (87%), followed by cord blood (CB) in 34 (11.6%) children. The use of alternative donors (77.8%) and presence of acute graft-vs-host disease (GVHD) (23.6%) were associated with an increased risk of viral and fungal infection. Bacterial infection was observed in 79 patients (27%); 220 patients (75.3%) were diagnosed with viral infection, and 35 patients (12%) developed fungal infection. The presence of fungal disease together with the presence of multiple infections during follow-up was associated with an increased risk of death (P < .001).

CONCLUSIONS

The clinical profile of HSCT-related infections in this cohort suggests that prognosis in allogeneic HSCT is influenced by the source of stem cells (CB having worse prognosis), presence of acute GVHD and complications arising from fungal infections. The appropriate management of these factors has the potential to improve the overall prognosis rates in pediatric allogeneic HSCT recipients.

Prevention and Treatment of Respiratory Virus Infection

There is increasing recognition of infections caused by respiratory viruses (RVs) as a major cause of morbidity and mortality in solid organ transplant (SOT) recipients, especially within the thoracic and pediatric population. In addition to their direct, cytopathic, and tissue-invasive effects, RVs can create an inflammatory environment, autoimmune responses, resulting in acute and chronic rejection, although this relationship remains controversial. A laboratory diagnosis in SOT with respiratory syndrome should be performed with nucleic acid amplification tests on respiratory specimens, mainly nasopharyngeal swabs (NPS) and bronchoalveolar lavage (BAL). Treatment options remain limited and consist of supportive care, reduction of immunosuppression, and, if available, antiviral therapy. The use of immunomodulatory agents remains a clinical dilemma. Since treatment options for RVs are limited, maximizing prevention measures against viral infections in SOT is mandatory. The main preventive strategy against influenza remains the administration of yearly inactivated influenza vaccine in all SOT. The aim of this review is to summarize the evidence-based recommendations on the diagnostic, preventive, and therapeutic strategies to decrease the burden of RV infections in SOT recipients.