Approach for defining human adenovirus infection and disease for central review adjudication in clinical studies

BACKGROUND

Pediatric allogeneic hematopoietic cell transplant (allo-HCT) recipients are at risk for morbidity and mortality from human adenovirus (HAdV). HAdV can be detected in an asymptomatic state, referred to as infection or with signs or symptoms of illness, referred to as disease. Standardized case definitions are needed to distinguish infection from disease and allow for consistent reporting in both observational cohort studies and therapeutic clinical trials.

METHODS

A working group of experts in virology, transplant infectious disease, and HCT was assembled to develop HAdV infection and disease definitions with the degree of certainty (i.e., possible, probable, and proven). Definitions were further refined through an iterative process and independently applied by two central review committees (CRCs) to 20 pediatric allo-HCT recipients with at least one HAdV-positive PCR.

RESULTS

Initial HAdV infection and disease definitions were developed and updated through an iterative process after reviewing clinical and virological details for 81 subjects with at least one positive HAdV PCR detected in a clinical specimen. Independent application of final definitions to 20 HAdV positive allo-HCT recipients by two CRCs yielded similar number of HAdV infection or disease events but with variation of degree of certainty for some events.

CONCLUSIONS

Application of definitions by a CRC for a study of HAdV infection and disease is feasible and can provide consistency in the assignment of outcomes. Definitions need further refinement to improve reproducibility and to provide guidance on determining clinical improvement or worsening after initial diagnosis of HAdV infection or disease.

Guidance for prevention and management of COVID-19 in children and adolescents: A consensus statement from the Pediatric Infectious Diseases Society Pediatric COVID-19 Therapies Taskforce

BACKGROUND

Since November 2019, the SARS-CoV-2 pandemic has created challenges for preventing and managing COVID-19 in children and adolescents. Most research to develop new therapeutic interventions or to repurpose existing ones has been undertaken in adults, and although most cases of infection in pediatric populations are mild, there have been many cases of critical and fatal infection. Understanding the risk factors for severe illness and the evidence for safety, efficacy, and effectiveness of therapies for COVID-19 in children is necessary to optimize therapy.

METHODS

A panel of experts in pediatric infectious diseases, pediatric infectious diseases pharmacology, and pediatric intensive care medicine from 21 geographically diverse North American institutions was re-convened. Through a series of teleconferences and web-based surveys and a systematic review with meta-analysis of data for risk factors, a guidance statement comprising a series of recommendations for risk stratification, treatment, and prevention of COVID-19 was developed and refined based on expert consensus.

RESULTS

There are identifiable clinical characteristics that enable risk stratification for patients at risk for severe COVID-19. These risk factors can be used to guide the treatment of hospitalized and non-hospitalized children and adolescents with COVID-19 and to guide preventative therapy where options remain available.

Mature Minor Doctrine Clarification Act: A Setback in Pediatric Immunizations

The Mature Minor Doctrine Clarification Act, a Tennessee bill stating that a healthcare provider may not provide vaccination to a minor without the informed consent of a parent/legal guardian, poses significant challenges to pediatric immunization. We outline changes implemented to our processes in response to this bill.

Evaluation of Continuous Infusion Vancomycin in a Pediatric Hematology/Oncology Population

BACKGROUND

Continuous infusion vancomycin (CIV) may benefit children who are unable to achieve therapeutic concentrations with intermittent vancomycin dosing and may facilitate outpatient administration by alleviating the burden of frequent dosing intervals. Previous studies have used variable dosing regimens and steady-state concentration goals. The purpose of this study was to evaluate the total daily dose (TDD) of CIV required to achieve therapeutic steady-state concentrations of 15-25 µg/mL in pediatric hematology/oncology patients.

METHODS

A single-center retrospective study was performed for patients treated with CIV from January 2017 to June 2019. The primary outcome was the TDD required to achieve therapeutic steady-state concentrations on CIV. Secondary outcomes included time to reach therapeutic steady-state concentrations, CIV indications and adverse events associated with CIV.

RESULTS

Data were collected for 71 courses of CIV in 60 patients. Median patient age was 4 years (range: 0.4-20 years). The median TDD required to achieve initial therapeutic concentrations was 50.3 mg/kg/d (interquartile range: 38.8-59.2) and was further divided into age-based cohorts. TDD in mg/kg was significantly lower in the older cohort (P < 0.001), but there was no statistically significant difference between age-based cohorts with TDD in mg/m2 (P = 0.97). Median time to achieve first therapeutic concentration was 19.3 hours (range: 8.6-72.3 hours). The most common indication for CIV was ease of outpatient administration (69.0%). Acute kidney injury incidence was minimal (4.2%).

CONCLUSIONS

CIV is associated with rapid attainment of target concentrations in pediatric hematology/oncology patients and is safe and well tolerated.

COVID-19 in Pediatric Patients With Acute Lymphoblastic Leukemia or Lymphoma

Importance

COVID-19 in pediatric patients with acute lymphoblastic leukemia or lymphoma (ALL/LLy) has not been described in detail and may affect chemotherapy administration and long-term outcomes.

Objective

To describe the clinical presentation of COVID-19 and chemotherapy modifications in pediatric patients with ALL/LLy.

Design, Setting, and Participants

This is a retrospective case series of patients at St Jude Children's Research Hospital and its affiliate sites with newly diagnosed ALL/LLy who were treated on the Total XVII protocol (NCT03117751) between March 30, 2020, and June 20, 2022. Participants included patients aged 1 to 18 years who were receiving protocol chemotherapy. Acute symptoms and chemotherapy modifications were evaluated for 60 days after the COVID-19 diagnosis, and viral clearance, adverse events, and second SARS-CoV-2 infections were followed up during the 27-month study period.

Exposures

SARS-CoV-2; all patients were screened at least weekly and at symptom onset and/or after known exposure to SARS-CoV-2.

Main Outcomes and Measures

Description of the spectrum of COVID-19 illness and chemotherapy modifications.

Results

Of 308 pediatric patients, 110 (36%) developed COVID-19 at a median age of 8.2 (IQR, 5.3-14.5) years. Sixty-eight patients (62%) were male. Most patients were in the continuation/maintenance phase of chemotherapy (101 [92%]). Severe disease was rare (7 [6%]) but was associated with older age, higher white blood cell counts at ALL/LLy diagnosis, lower absolute lymphocyte counts at COVID-19 diagnosis, abnormal chest imaging findings, and SARS-CoV-2 reinfection. Rare but serious thrombotic events included pulmonary embolism and cerebral venous sinus thrombosis (n = 1 for each). No multisystem inflammatory syndrome in children or death was seen. SARS-CoV-2 reinfection occurred in 11 patients (10%) and was associated with older age and with receiving standard or high-risk vs low-risk ALL/LLy therapy. Chemotherapy interruptions occurred in 96 patients (87%) and were longer for patients with severe disease, SARS-CoV-2 reinfection, and/or a COVID-19 diagnosis during the pre-Omicron variant period vs the post-Omicron period (after December 27, 2021).

Conclusions and Relevance

In this case series of COVID-19 in pediatric patients with ALL/LLy, severe COVID-19 was rare, but chemotherapy administration was affected in most patients. Long-term studies are needed to establish the outcomes of COVID-19 in this population.

Clinical Outcomes of Human Rhinovirus/Enterovirus Infection in Pediatric Hemopoietic Cell Transplant Patients

BACKGROUND

Respiratory viral infections are common among pediatric transplant patients, with human rhinovirus (HRV) being the most frequent. In pediatric patients undergoing hemopoietic cell transplant (HCT), infection with HRV has been associated with progression to lower respiratory tract infection (LRTI) and adverse outcomes. We describe the clinical presentation and outcomes of HRV infection in children undergoing HCT.

METHODS

Single-center retrospective study. HCT recipients who were positive for HRV/EV (HRV+) or negative for any respiratory virus (VN) by BioFire® FilmArray® panel between October 2014 and December 2017, were included. Primary outcomes were progression to LRTI, ICU admission, all-cause mortality at 3 and 6 months, and respiratory event-related mortality at 6 months.

RESULTS

227 patients (160 allogeneic HCT) were included. Of all patients, 108/227 (47.6%) were HRV+. From all HRV+, 95/108 (88%) were symptomatic and 68/107 (63.6%) of the diagnosis were made pretransplant. The median age of HRV+ was significantly lower than VN patients (5 vs 10 years). Cough and rhinorrhea were more frequently observed in HRV+ (53.7 and 60% vs 19.8 and 22.8%, respectively). No differences were found between both groups pretransplant and overall in rates progression to LRTI, ICU admission, mechanical ventilation, all-cause within 3 and 6 months, and mortality related with respiratory failure. No significant association was found between the severity of respiratory disease and the type of conditioning, type of transplant, or absolute lymphocyte count.

CONCLUSIONS

HRV infection is frequently detected in HCT recipients but is not associated with severity of respiratory disease, need for intensive care unit or mortality, including those diagnosed before transplant, suggesting that delaying HCT in this scenario may not be needed. Multicenter larger studies are required to confirm these findings.

Approach to hematopoietic cell transplant candidates with respiratory viral detection

The management of respiratory viruses prior to hematopoietic cell transplant (HCT) can be controversial and requires special consideration of host factors, transplant parameters, and the specific respiratory virus (RV). In the setting of adenovirus (ADV), human metapneumovirus (HMPV), influenza, parainfluenza virus (PIV), and respiratory syncytial virus (RSV) detection prior to hematopoietic cell transplant (HCT), clinical practice guidelines recommend transplant delay when possible; however, there is much more ambiguity when other respiratory viruses, such as seasonal coronaviruses (CoVs), human rhinovirus (HRV), and SARS-CoV-2, are detected. Our aims for this review include detailing clinical practical guidelines and reviewing current literature on pre-transplant respiratory viral infections (RVIs), including antiviral therapies and prevention strategies, when available. We will center our discussion on three representative clinical scenarios, with the goal of providing practical guidance to clinicians.

Employee investigation and contact tracing program in a pediatric cancer hospital to mitigate the spread of COVID-19 among the workforce, patients, and caregivers

Background

Case investigations and contact tracing are essential disease control measures used by health departments. Early in the pandemic, they were seen as a key strategy to stop COVID-19 spread. The CDC urged rapid action to scale up and train a large workforce and collaborate across public and private agencies to halt COVID-19 transmission.

Methods

We developed a program for case investigation and contact tracing that followed CDC and local health guidelines, compliant with the Occupational Safety and Health Administration (OSHA) regulations and tailored to the needs and resources of our institution. Program staff were trained and assessed for competency before joining the program.

Results

From March 2020 to May 2021, we performed 838 COVID-19 case investigations, which led to 136 contacts. Most employees reported a known SARS-CoV-2 exposure from the community (n = 435) or household (n = 343). Only seven (5.1%) employees were determined as more likely than not to have SARS-CoV-2 infection related to workplace exposure, and when so, lapses in following the masking recommendations were identified. Between June 2021-February 2022, our program adjusted to the demand of the different waves, particularly omicron, by significantly reducing the amount of data collected. No transmission from employees to patients or caregivers was observed during this period.

Conclusion

Prompt implementation of case investigation and contact tracing is possible, and it effectively reduces workplace exposures. This approach can be adapted to suit the specific needs and requirements of various healthcare settings, particularly those serving the most vulnerable patient populations.

Digital PCR to Measure SARS-CoV-2 RNA, Variants, and Outcomes in Youth

BACKGROUND

The role of SARS-CoV-2 viral load in predicting contagiousness, disease severity, transmissibility, and clinical decision-making continues to be an area of great interest. However, most studies have been in adults and have evaluated SARS-CoV-2 loads using cycle thresholds (Ct) values, which are not standardized preventing consistent interpretation critical to understanding clinical impact and utility. Here, a quantitative SARS-CoV-2 reverse-transcription digital PCR (RT-dPCR) assay normalized to WHO International Units was applied to children at risk of severe disease diagnosed with COVID-19 at St. Jude Children's Research Hospital between March 28, 2020, and January 31, 2022.

METHODS

Demographic and clinical information from children, adolescents, and young adults treated at St. Jude Children's Research Hospital were abstracted from medical records. Respiratory samples underwent SARS-CoV-2 RNA quantitation by RT-dPCR targeting N1 and N2 genes, with sequencing to determine the genetic lineage of infecting virus.

RESULTS

Four hundred and sixty-two patients aged 0-24 years (median 11 years old) were included during the study period. Most patients were infected by the omicron variant (43.72%), followed by ancestral strain (22.29%), delta (13.20%), and alpha (2.16%). Viral load at presentation ranged from 2.49 to 9.14 log10 IU/mL, and higher viral RNA loads were associated with symptoms (OR 1.32; CI 95% 1.16-1.49) and respiratory disease (OR 1.23; CI 95% 1.07-1.41). Viral load did not differ by SARS-CoV-2 variant, vaccination status, age, or baseline diagnosis.

CONCLUSIONS

SARS-CoV-2 RNA loads predict the presence of symptomatic and respiratory diseases. The use of standardized, quantitative methods is feasible, allows for replication, and comparisons across institutions, and has the potential to facilitate consensus quantitative thresholds for risk stratification and treatment.

SARS-CoV-2 infection in high-risk children following tixagevimab-cilgavimab (Evusheld) pre-exposure prophylaxis: a single-center observational study

From 8 December 2021 to 26 January 2023, tixagevimab-cilgavimab (T-C) was authorized for pre-exposure prophylaxis of COVID-19. During this period, we used a multidisciplinary team to communicate, screen, approach, and administer T-C to eligible patients. Twenty-seven patients were eligible. Of these, 24 (88.9%) received at least one dose of T-C and three patients received two doses. Majority of patients were White, non-Hispanic, and women. Only two patients had COVID-19 prior to receiving T-C. Seventeen (70.8%) had received two or more doses of SARS-CoV-2 vaccine. No serious adverse events were noted. Seven patients developed SARS-CoV-2 infection within 180 days of receiving T-C (median 102 days; range 28-135), and only one patient developed severe COVID-19 requiring intensive mechanical ventilation in the intensive care unit.

Attitudes toward COVID-19 vaccine among pediatric patients with sickle cell disease and their caregivers

OBJECTIVE

To evaluate attitudes toward vaccination and vaccine uptake regarding coronavirus disease 2019 (COVID-19) among pediatric patients with sickle cell disease (SCD) and their caregivers.

PROCEDURE

Adolescent patients and caregivers of children with SCD were surveyed during routine clinic visits; we then conducted a logistic regression analysis to understand differences in vaccine status, while qualitative responses were coded thematically.

RESULTS

Among respondents, the overall vaccination rate among adolescents and caregivers was 49% and 52%, respectively. Among the unvaccinated, 60% and 68% of adolescents and caregivers, respectively, preferred to remain unvaccinated, most commonly due to lack of perceived personal benefit from vaccination or mistrust in the vaccine. Multivariate logistic regression analysis showed that child's age (odds ratio [OR] = 1.1, 95% confidence interval [CI]: 1.0-1.2, p < .01) and caregiver education (measured by the Economic Hardship Index [EHI] score, OR = 0.76, 95% CI: 0.74-0.78, p < .05) were independent predictors of getting vaccinated.

CONCLUSION

Despite the increased risk of severe illness due to COVID-19 in patients with SCD, vaccine hesitancy remains high in this population of families whose children have SCD. Fortunately, the reasons cited for deferring vaccination among those who are unvaccinated were largely due to barriers that may be overcome with quality communication around the utility of the vaccine and information about vaccine safety.

Clinical Correlation of Adenoviral Load in the Respiratory Tract Measured by Digital PCR in Immunocompromised Children

Immunocompromised patients can have life-threatening adenoviral infection. Viral load in blood and stool is commonly used to guide antiviral therapy. We developed and evaluated a digital polymerase chain reaction assay to quantify human adenovirus in the respiratory tract and showed that higher peak load correlates with disseminated infection, mechanical ventilation, and death.

Vaccines against SARS-CoV-2 are safe to administer in patients with antibodies to pegaspargase

OBJECTIVE

Allergic reactions to pegaspargase during ALL therapy are typically due to antibodies against polyethylene glycol (PEG), which is also used as a stabilizing agent in mRNA-based SARS-CoV-2 vaccines. To evaluate the safety of these vaccines in patients with anti-pegaspargase antibodies.

METHODS

We retrospectively reviewed the records of patients treated for ALL who had received SARS-CoV-2 vaccinations. All patients had antibodies against pegaspargase assayed during ALL therapy prospectively and in response to clinical allergies. Symptoms of intolerance to vaccination were gathered retrospectively from chart abstraction.

RESULTS

SARS-CoV-2 vaccination was well tolerated in all 78 patients with prior exposure to pegaspargase as part of their leukemia therapy. No reactions were observed in the 54 patients without a history of anti-pegaspargase antibodies or in 19 patients with antibodies who received mRNA vaccination. 1 patient who received the polysorbate containing Janssen vaccine experienced mild symptoms after vaccination not meeting the criteria of clinical allergy which spontaneously resolved within 25 minutes.

CONCLUSION

SARS-CoV-2 vaccination is safe in this population.

Human Astrovirus VA1 Encephalitis in Pediatric Patients With Cancer: Report of 2 Cases and Review of the Literature

Novel human astroviruses (HAstVs) have recently been implicated as rare causes of fatal encephalitis in immunocompromised patients, for which there is no proven treatment. We report 2 cases from our institution in which HAstV-VA1 was detected in the cerebrospinal fluid by metagenomic next-generation sequencing after the initial evaluation revealed no etiology.

Prediction of Symptomatic SARS-CoV-2 infection by Quantitative Digital PCR Normalized to International Units

Although numerous studies have evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using cycle threshold (Ct) values as a surrogate of viral ribonucleic acid (RNA) load, few studies have used standardized, quantitative methods. We validated a quantitative SARS-CoV-2 digital polymerase chain reaction assay normalized to World Health Organization International Units and correlated viral RNA load with symptoms and disease severity.

covidscreen: a web app and R Package for assessing asymptomatic COVID-19 testing strategies

Background

COVID-19 has caused over 305 million infections and nearly 5.5 million deaths globally. With complete eradication unlikely, organizations will need to evaluate their risk and the benefits of mitigation strategies, including the effects of regular asymptomatic testing. We developed a web application and R package that provides estimates and visualizations to aid the assessment of organizational infection risk and testing benefits to facilitate decision-making, which combines internal and community information with malleable assumptions.

Results

Our web application, covidscreen, presents estimated values of risk metrics in an intuitive graphical format. It shows the current expected number of active, primarily community-acquired infections among employees in an organization. It calculates and explains the absolute and relative risk reduction of an intervention, relative to the baseline scenario, and shows the value of testing vaccinated and unvaccinated employees. In addition, the web interface allows users to profile risk over a chosen range of input values. The performance and output are illustrated using simulations and a real-world example from the employee testing program of a pediatric oncology specialty hospital.

Conclusions

As the COVID-19 pandemic continues to evolve, covidscreen can assist organizations in making informed decisions about whether to incorporate covid test based screening as part of their on-campus risk-mitigation strategy. The web application, R package, and source code are freely available online (see “Availability of data and materials”).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13718-4.

A nucleic acid amplification test-based strategy does not help inform return to work for healthcare workers with COVID-19

Objective

The objective of this study is to assess the utility of a nucleic acid amplification test‐based approach to shorten isolation of healthcare workers (HCWs) with COVID‐19 in the setting of the highly transmissible omicron variant.

Methods

Between December 24, 2021, and January 5, 2022, HCWs who tested positive for SARS‐CoV‐2 were retested with PCR at least 5 days since onset of symptoms.

Results

Forty‐six sequential fully COVID‐19 vaccinated HCWs who had tested positive for SARS‐CoV‐2 underwent follow‐up testing. All the samples were confirmed as omicron variants and only four (8.7%) were negative in the follow‐up test performed at a median of 6 (range 5–12) since onset of symptoms.

Conclusions

Implementation of a test‐based strategy is logistically challenging, increases costs, and did not lead to shorter isolation in our institution.

The successful use of eculizumab for treatment of thrombotic microangiopathy in pediatric acute SARS-CoV2 infection and multisystem inflammatory syndrome in children

Not available.

An adaptive, asymptomatic SARS-CoV-2 workforce screening program providing real-time, actionable monitoring of the COVID-19 pandemic

COVID-19 remains a challenge worldwide, and testing of asymptomatic individuals remains critical to pandemic control measures. Starting March 2020, a total of 7497 hospital employees were tested at least weekly for SARS CoV-2; the cumulative incidence of asymptomatic infections was 5.64%. Consistently over a 14-month period half of COVID-19 infections (414 of 820, total) were detected through the asymptomatic screening program, a third of whom never developed any symptoms during follow-up. Prompt detection and isolation of these cases substantially reduced the risk of potential workplace and outside of workplace transmission. COVID-19 vaccinations of the workforce were initiated in December 2020. Twenty-one individuals tested positive after being fully vaccinated (3.9 per 1000 vaccinated). Most (61.9%) remained asymptomatic and in majority (75%) the virus could not be sequenced due to low template RNA levels in swab samples. Further routine testing of vaccinated asymptomatic employees was stopped and will be redeployed if needed; routine testing for those not vaccinated continues. Asymptomatic SARS-CoV-2 testing, as a part of enhanced screening, monitors local dynamics of the COVID-19 pandemic and can provide valuable data to assess the ongoing impact of COVID-19 vaccination and SARS-CoV-2 variants, inform risk mitigation, and guide adaptive, operational planning including titration of screening strategies over time, based on infection risk modifiers such as vaccination.

Infectious Complications in Pediatric, Adolescent and Young Adult Patients Undergoing CD19-CAR T Cell Therapy

CD19-specific chimeric antigen receptor (CAR) T cell therapy has changed the treatment paradigm for pediatric, adolescent and young adult (AYA) patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, data on the associated infectious disease challenges in this patient population are scarce. Knowledge of infections presenting during treatment, and associated risk factors, is critical for pediatric cellular therapy and infectious disease specialists as we seek to formulate effective anti-infective prophylaxis, infection monitoring schemas, and empiric therapy regimens. In this work we describe our institutional experience in a cohort of 38 pediatric and AYA patients with CD19-positive malignancy treated with lymphodepleting chemotherapy (fludarabine/cyclophosphamide) followed by a single infusion of CD19-CAR T cells (total infusions, n=39), including tisagenlecleucel (n=19; CD19/4-1BB) or on an institutional clinical trial (n=20; CD19/4-1BB; NCT03573700). We demonstrate that infections were common in the 90 days post CAR T cells, with 19 (50%) patients experiencing a total of 35 infections. Most of these (73.7%) occurred early post infusion (day 0 to 28; infection density of 2.36 per 100 patient days-at-risk) compared to late post infusion (day 29 to 90; infection density 0.98 per 100 patient days-at-risk), respectively. Bacterial infections were more frequent early after CAR T cell therapy, with a predominance of bacterial blood stream infections. Viral infections occurred throughout the post infusion period and included primarily systemic reactivations and gastrointestinal pathogens. Fungal infections were rare. Pre-infusion disease burden, intensity of bridging chemotherapy, lymphopenia post lymphodepleting chemotherapy/CAR T cell infusion and development of CAR-associated hemophagocytic lymphohistiocytosis (carHLH) were all significantly associated with either infection density or time to first infection post CAR T cell infusion. A subset of patients (n=6) had subsequent CAR T cell reinfusion and did not appear to have increased risk of infectious complications. Our experience highlights the risk of infections after CD19-CAR T cell therapy, and the need for continued investigation of infectious outcomes as we seek to improve surveillance, prophylaxis and treatment algorithms.

IL-1β Promotes Expansion of IL-33+ Lung Epithelial Stem Cells Following RSV Infection During Infancy

Respiratory syncytial virus (RSV)-induced immunopathogenesis and disease severity in neonatal mice and human infants have been related to elevated pulmonary IL-33. Thus, targeting IL-33 has been suggested as a potential therapy for respiratory viral infections. Yet, the regulatory mechanisms on IL-33 during early life remain unclear. Here, using a neonatal mouse model of RSV, we demonstrate that IL-1β positively regulates but is not required for RSV-induced expression of pulmonary IL-33 in neonatal mice early after the initial infection. Exogenous IL-1β upregulates RSV-induced IL-33 expression by promoting the proliferation of IL-33pos lung epithelial stem/progenitor cells (EpiSPC). These cells are exclusively detected in RSV-infected neonatal rather than adult mice, partially explaining the IL-1β-independent IL-33 expression in RSV-infected adult mice. Furthermore, IL-1β aggravates IL-33 mediated Th2 biased immunopathogenesis upon reinfection. Collectively, our study demonstrates that IL-1β exacerbates IL-33 mediated RSV immunopathogenesis by promoting the proliferation of IL-33pos EpiSPC in early life.

Clinical experience of coronavirus disease 2019 in hematopoietic cell transplant and chimeric antigen receptor T-cell recipients

PURPOSE OF REVIEW

To discuss the clinical experience of coronavirus disease 2019 (COVID-19) in hematopoietic cell transplant and chimeric antigen receptor T-cell therapy recipients over the past year and to identify key knowledge gaps for future research.

RECENT FINDINGS

Immunocompromised individuals and those with chronic health conditions are especially susceptible to infections, which have had a disproportionate impact on health outcomes during the COVID-19 pandemic. Several studies have evaluated the clinical characteristics and outcomes of transplant and cellular therapy (TCT) recipients who developed COVID-19. Age, sex, comorbid conditions, and social determinants of health are important predictors of the risk of severe acute respiratory syndrome coronavirus 2 infection and of the eventual severity of the disease. Various treatment approaches have been investigated over the last year. The paradigm of management strategies continues to evolve as more experience is accumulated.

SUMMARY

In this review, we summarize some important findings as they relate to the clinical characteristics of TCT recipients who develop COVID-19. We also discuss some treatment approaches that are currently recommended and opine on vaccination in this population.

Fatal enhanced respiratory syncytial virus disease in toddlers

In 1967, two toddlers immunized with a formalin-inactivated vaccine against respiratory syncytial virus (FIRSV) in the United States died from enhanced RSV disease (ERD), a severe form of illness resulting from aberrant priming of the antiviral immune response during vaccination. Up to 80% of immunized children subsequently exposed to wild-type virus were hospitalized. These events hampered RSV vaccine development for decades. Here, we provide a characterization of the clinical, immunopathological, and transcriptional signature of fatal human ERD, outlining evidence for safety evaluation of RSV vaccines and a framework for understanding disease enhancement for pathogens in general.

Asymptomatic and Symptomatic SARS-CoV-2 Infections After BNT162b2 Vaccination in a Routinely Screened Workforce

This study aims to describe an association between the Pfizer-BioNTech (BNT162b2) vaccine and decreased risk of symptomatic and asymptomatic infections with SARS-CoV-2 in hospital employees.

The Aerogen® Solo Is an Alternative to the Small Particle Aerosol Generator (SPAG-2) for Administration of Inhaled Ribavirin

Respiratory syncytial virus (RSV) is associated with adverse outcomes among immunocompromised patients. Inhaled ribavirin has been shown to improve mortality rates. The Small-Particle Aerosol Generator delivery system (SPAG-2) is the only FDA-cleared device to deliver inhaled ribavirin. However, it is difficult to set up and maintain. We developed a method for delivery of this medication using the vibrating mesh nebulizer (Aerogen^®). We did not observe any adverse events with this method.

Rothia mucilaginosa Infections in Pediatric Cancer Patients

We performed a retrospective study to determine the epidemiology of Rothia mucilaginosa infections among pediatric cancer patients. Over 20 years, 37 cases were identified; 27% developed complications, but there was no infection-related mortality. All cases were successfully treated with vancomycin.

Role of Type I Interferon (IFN) in the Respiratory Syncytial Virus (RSV) Immune Response and Disease Severity

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract disease in children <2 years of age. Increased morbidity and mortality have been reported in high-risk patients, such as premature infants, patients with cardiac disease, and severely immune compromised patients. Severe disease is associated with the virulence of the virus as well as host factors specifically including the innate immune response. The role of type I interferons (IFNs) in the response to RSV infection is important in regulating the rate of virus clearance and in directing the character of the immune response, which is normally associated with protection and less severe disease. Two RSV non-structural proteins, NS1 and NS2, as well as the envelope G glycoprotein are known to suppress type I IFN production and a robust type I IFN response to RSV does not occur in human infants or neonatal mouse models of RSV infection. Additionally, presence of type I IFNs are associated with mild symptoms in infants and administration of IFN-α prior to infection of neonatal mice with RSV reduces immunopathology. This evidence has driven RSV prophylaxis and therapeutic efforts to consider strategies for enhancing type I IFN production.

Respiratory Viral Infections in Patients With Cancer or Undergoing Hematopoietic Cell Transplant

Survival rates for pediatric cancer have steadily improved over time but it remains a significant cause of morbidity and mortality among children. Infections are a major complication of cancer and its treatment. Community acquired respiratory viral infections (CRV) in these patients increase morbidity, mortality and can lead to delay in chemotherapy. These are the result of infections with a heterogeneous group of viruses including RNA viruses, such as respiratory syncytial virus (RSV), influenza virus (IV), parainfluenza virus (PIV), metapneumovirus (HMPV), rhinovirus (RhV), and coronavirus (CoV). These infections maintain a similar seasonal pattern to those of immunocompetent patients. Clinical manifestations vary significantly depending on the type of virus and the type and degree of immunosuppression, ranging from asymptomatic or mild disease to rapidly progressive fatal pneumonia Infections in this population are characterized by a high rate of progression from upper to lower respiratory tract infection and prolonged viral shedding. Use of corticosteroids and immunosuppressive therapy are risk factors for severe disease. The clinical course is often difficult to predict, and clinical signs are unreliable. Accurate prognostic viral and immune markers, which have become part of the standard of care for systemic viral infections, are currently lacking; and management of CRV infections remains controversial. Defining effective prophylactic and therapeutic strategies is challenging, especially considering, the spectrum of immunocompromised patients, the variety of respiratory viruses, and the presence of other opportunistic infections and medical problems. Prevention remains one of the most important strategies against these viruses. Early diagnosis, supportive care and antivirals at an early stage, when available and indicated, have proven beneficial. However, with the exception of neuraminidase inhibitors for influenza infection, there are no accepted treatments. In high-risk patients, pre-emptive treatment with antivirals for upper respiratory tract infection (URTI) to decrease progression to LRTI is a common strategy. In the future, viral load and immune markers may prove beneficial in predicting severe disease, supporting decision making and monitor treatment in this population.

Type I Interferon Potentiates IgA Immunity to Respiratory Syncytial Virus Infection During Infancy

Respiratory syncytial virus (RSV) infection is the most frequent cause of hospitalization in infants and young children worldwide. Although mucosal RSV vaccines can reduce RSV disease burden, little is known about mucosal immune response capabilities in children. Neonatal or adult mice were infected with RSV; a subset of neonatal mice received interferon alpha (IFN-α) (intranasal) prior to RSV infection. B cells, B cell activating factor (BAFF) and IgA were measured by flow cytometry. RSV specific IgA was measured in nasal washes. Nasal associated lymphoid tissue (NALT) and lungs were stained for BAFF and IgA. Herein, we show in a mouse model of RSV infection that IFN-α plays a dual role as an antiviral and immune modulator and age-related differences in IgA production upon RSV infection can be overcome by IFN-α administration. IFN-α administration before RSV infection in neonatal mice increased RSV-specific IgA production in the nasal mucosa and induced expression of the B-cell activating factor BAFF in NALT. These findings are important, as mucosal antibodies at the infection site, and not serum antibodies, have been shown to protect human adults from experimental RSV infection.

Interleukin-13 associates with life-threatening rhinovirus infections in infants and young children

OBJECTIVE

Delineate risk factors associated with severe hypoxemia (O₂ sat ≤87%) in infants and children younger than 2 years hospitalized with single pathogen HRV infection.

STUDY DESIGN

Prospective study in a yearly catchment population of 56 560 children <2 years old between 2011 and 2013 in Argentina. All children with respiratory signs and O₂ sat <93% on admission were included. HRV infections were identified by reverse transcriptase-polymerase chain reaction. Epidemiologic, clinical, viral, and immunological risk factors were assessed.

RESULTS

Among 5012 hospitalized patients, HRV was detected as a single pathogen in 347 (6.92%) subjects. Thirty-two (9.2%) had life-threatening disease. Traditional risk factors for severe bronchiolitis did not affect severity of illness. HRV viral load, HRV groups, and type II and III interferons did not associate with severe hypoxemia. Interleukin-13 Levels in respiratory secretions at the time of admission (OR = 7.43 (3-18.4); P < 0.001 for IL-13 >10 pg/mL) predisposed to life-threatening disease.

CONCLUSIONS

Targeted interventions against IL-13 should be evaluated to decrease severity of HRV illness in infancy and early childhood.

Alcohol during pregnancy worsens acute respiratory infections in children

AIM

This study explored whether alcohol consumption during pregnancy increased the risk of life-threatening respiratory infections in children.

METHODS

We prospectively evaluated children under the age of two years admitted to hospitals in Buenos Aires, Argentina, with severe acute respiratory infections during the winters of 2011 and 2012. Information on maternal alcohol consumption during the third trimester of pregnancy was collected using standardised questionnaires and categorised as never, low if it was once a week and high if it was equal or more than once a week.

RESULTS

Of the 3423 children hospitalised with acute respiratory infection, 2089 (63.7%) had respiratory syncytial virus (RSV). Alcohol consumption during the last trimester was reported by 398 mothers (12.4%) and categorised as low (n = 210, 6.5%) or high (n = 188, 5.9%). A greater effect on life-threatening respiratory infection, defined as oxygen saturation of or up to 87%, was observed with higher alcohol intake due to all viruses and specifically RSV in the logistic regression analyses. Alcohol consumption was strongly associated with life-threatening disease, particularly in boys whose adjusted odds ratio rose from 3.67 to 13.52 when their mothers drank alcohol.

CONCLUSION

Alcohol consumption during pregnancy was associated with life-threatening respiratory infections in boys.

TLR4 genotype and environmental LPS mediate RSV bronchiolitis through Th2 polarization

While 30%-70% of RSV-infected infants develop bronchiolitis, 2% require hospitalization. It is not clear why disease severity differs among healthy, full-term infants; however, virus titers, inflammation, and Th2 bias are proposed explanations. While TLR4 is associated with these disease phenotypes, the role of this receptor in respiratory syncytial virus (RSV) pathogenesis is controversial. Here, we evaluated the interaction between TLR4 and environmental factors in RSV disease and defined the immune mediators associated with severe illness. Two independent populations of infants with RSV bronchiolitis revealed that the severity of RSV infection is determined by the TLR4 genotype of the individual and by environmental exposure to LPS. RSV-infected infants with severe disease exhibited a high GATA3/T-bet ratio, which manifested as a high IL-4/IFN-γ ratio in respiratory secretions. The IL-4/IFN-γ ratio present in infants with severe RSV is indicative of Th2 polarization. Murine models of RSV infection confirmed that LPS exposure, Tlr4 genotype, and Th2 polarization influence disease phenotypes. Together, the results of this study identify environmental and genetic factors that influence RSV pathogenesis and reveal that a high IL-4/IFN-γ ratio is associated with severe disease. Moreover, these molecules should be explored as potential targets for therapeutic intervention.

T helper type 2 bias and type 17 suppression in primary dengue virus infection in infants and young children

BACKGROUND

The immune response to dengue virus (DENV) primary infection in infants and young children is not well characterized. In Northern Argentina, >90% of the population was DENV-naïve before the 2009 outbreak, allowing evaluation of age-dependent primary responses to infection.

METHODS

We conducted a comparative study of the immune response to DENV in 27 infected infants, young children and their mothers. Lymphocyte T helper (Th) 1, Th2, Th17 and inflammatory responses were assayed in blood during the 2009 DENV-1 epidemic.

RESULTS

The immune response to DENV-1 was significantly biased to Th2 in infected infants and young children, compared to infants with other febrile illnesses (for IL-4 p < 0.001) and to their infected mothers (for IL-4 p < 0.01). In addition, IL-17 suppression was observed in the memory response to DENV-1 in infected infants (p < 0.01 vs placebo).

CONCLUSION

Age-related differences in the primary response to DENV, characterized by an immature Th2 polarization and Th17 suppression in infants, should be studied further in order to expand our understanding of the mechanism of dengue pathogenesis.

Pediatric hospitalizations associated with 2009 pandemic influenza A (H1N1) in Argentina

BACKGROUND

While the Northern Hemisphere experiences the effects of the 2009 pandemic influenza A (H1N1) virus, data from the recent influenza season in the Southern Hemisphere can provide important information on the burden of disease in children.

METHODS

We conducted a retrospective case series involving children with acute infection of the lower respiratory tract or fever in whom 2009 H1N1 influenza was diagnosed on reverse-transcriptase polymerase-chain-reaction assay and who were admitted to one of six pediatric hospitals serving a catchment area of 1.2 million children. We compared rates of admission and death with those among age-matched children who had been infected with seasonal influenza strains in previous years.

RESULTS

Between May and July 2009, a total of 251 children were hospitalized with 2009 H1N1 influenza. Rates of hospitalization were double those for seasonal influenza in 2008. Of the children who were hospitalized, 47 (19%) were admitted to an intensive care unit, 42 (17%) required mechanical ventilation, and 13 (5%) died. The overall rate of death was 1.1 per 100,000 children, as compared with 0.1 per 100,000 children for seasonal influenza in 2007. (No pediatric deaths associated with seasonal influenza were reported in 2008.) Most deaths were caused by refractory hypoxemia in infants under 1 year of age (death rate, 7.6 per 100,000).

CONCLUSIONS

Pandemic 2009 H1N1 influenza was associated with pediatric death rates that were 10 times the rates for seasonal influenza in previous years.