Risk Analysis of Respiratory Syncytial Virus Among Infants in the United States by Birth Month.

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of morbidity and mortality among US infants. A child's calendar birth month determines their age at first exposure(s) to RSV. We estimated birth month-specific risk of medically attended (MA) RSV lower respiratory tract infection (LRTI) among infants during their first RSV season and first year of life (FYOL). METHODS: We analyzed infants born in the USA between July 2016 and February 2020 using three insurance claims databases (two commercial, one Medicaid). We classified infants' first MA RSV LRTI episode by the highest level of care incurred (outpatient, emergency department, or inpatient), employing specific and sensitive diagnostic coding algorithms to define index RSV diagnoses. In our main analysis, we focused on infants' first RSV season. In our secondary analysis, we compared the risk of MA RSV LRTI during infants' first RSV season to that of their FYOL. RESULTS: Infants born from May through September generally had the highest risk of first-season MA RSV LRTI-approximately 6-10% under the specific RSV index diagnosis definition and 16-26% under the sensitive. Infants born between October and December had the highest risk of RSV-related hospitalization during their first season. The proportion of MA RSV LRTI events classified as inpatient ranged from 9% to 54% (specific) and 5% to 33% (sensitive) across birth month and comorbidity group. Through the FYOL, the overall risk of MA RSV LRTI is comparable across birth months within each claims database (6-11% under the specific definition, 17-30% under the sensitive), with additional cases progressing to care at outpatient or ED settings. CONCLUSIONS: Our data support recent national recommendations for the use of nirsevimab in the USA. For infants born at the tail end of an RSV season who do not receive nirsevimab, a dose administered prior to the onset of their second RSV season could reduce the incidence of outpatient- and ED-related events.

Medically Attended Illness due to Respiratory Syncytial Virus Infection Among Infants Born in the United States Between 2016 and 2020.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of infant hospitalization in the United States. Preterm infants and those with select comorbidities are at highest risk of RSV-related complications. However, morbidity due to RSV infection is not confined to high-risk infants. We estimated the burden of medically attended (MA) RSV-associated lower respiratory tract infection (LRTI) among infants in the United States. METHODS: We analyzed commercial (MarketScan Commercial [MSC], Optum Clinformatics [OC]), and Medicaid (MarketScan Medicaid [MSM]) insurance claims data for infants born between April 2016 and February 2020. Using both specific and sensitive definitions of MA RSV LRTI, we estimated the burden of MA RSV LRTI during infants' first RSV season, stratified by gestational age, comorbidity status, and highest level of medical care associated with the MA RSV LRTI diagnosis. RESULTS: According to the specific definition 75.0% (MSC), 78.6% (MSM), and 79.6% (OC) of MA RSV LRTI events during infants' first RSV season occurred among term infants without known comorbidities. CONCLUSIONS: Term infants without known comorbidities account for up to 80% of the MA RSV LRTI burden in the United States during infants' first RSV season. Future prevention efforts should consider all infants.

The Logistics and Coordination of Respiratory Syncytial Virus Immunoprophylaxis Use Among US Pediatric Specialists.

This study was conducted to survey US pediatric specialists about administration of respiratory syncytial virus (RSV) immunoprophylaxis, communication patterns among physicians and parents, and barriers to access. Separate surveys were sent to neonatologists, pediatricians, pediatric pulmonologists, and pediatric cardiologists. Most physicians (≥93.5%) routinely recommended immunoprophylaxis to high-risk children. Most respondents (≥71.8%) reported that >50.0% of eligible infants and young children received each monthly dose throughout the RSV season, with the first dose most commonly administered before discharge from the birth hospitalization. To ensure receipt of subsequent doses, specialists frequently scheduled a follow-up visit at the end of the current appointment. All specialists reported insurance denials as the biggest obstacle to the administration of immunoprophylaxis to high-risk children. These findings may be used to improve adherence to immunoprophylaxis by enhancing education and physician-parent communications about severe RSV disease prevention, and by reducing known barriers to use of this preventive therapy.

Perceived Risk of Severe Respiratory Syncytial Virus Disease and Immunoprophylaxis Use Among US Pediatric Specialists.

This study was conducted to assess the perception of US pediatric specialists of respiratory syncytial virus (RSV) disease risk and determine their clinical practices regarding immunoprophylaxis for high-risk children. Separate surveys were sent to neonatologists, pediatricians, pediatric pulmonologists, and pediatric cardiologists. Data were collected using structured questions requiring quantitative responses. Most neonatologists and pediatricians (>82.7%) reported a high clinical need for RSV immunoprophylaxis in preterm infants <32 weeks' gestational age. Pediatric pulmonologists and pediatric cardiologists suggested that health conditions indicative of chronic lung disease of prematurity and hemodynamically significant congenital heart disease, respectively, confer eligibility for RSV immunoprophylaxis. Agreement with the changes in the 2014 American Academy of Pediatrics guidance for RSV immunoprophylaxis was mixed among respondents from the 4 specialties. Survey findings may provide a basis to improve education about risk for severe RSV disease and evaluate changes in physician use of RSV immunoprophylaxis based on the 2014 guidance.

Three monthly doses of palivizumab are not adequate for 5-month protection: a population pharmacokinetic analysis.

Recent guidelines in British Columbia, Canada have suggested that the use of a maximum of 3 monthly doses of palivizumab 15 mg/kg intramuscularly for RSV immunoprophylaxis of high risk infants born prior to the RSV season is adequate to provide protection against severe RSV disease for a 5-month RSV season. Efficacy was established, however, with 2 large, randomized controlled clinical studies using 5 monthly doses of immunoprophylaxis. To evaluate the differences in expected palivizumab exposures between the 2 dosing regimens (3 vs 5 monthly doses across a 5-month period), we used a population pharmacokinetic (PK) model that was developed using palivizumab PK data collected from 22 clinical studies with a total of 1800 subjects. This model adequately described observed palivizumab concentrations from the different pediatric studies and was subsequently used to simulate expected palivizumab serum concentrations for 3 monthly doses compared with 5 monthly doses in children younger than 24 months with chronic lung disease of prematurity and infants younger than 6 months postnatal age who were born at ≤ 35 weeks gestational age. Results from the population PK model indicated lower serum concentrations of palivizumab during the fourth and fifth months, after an abbreviated 3-monthly-dose regimen when compared with the mean trough concentrations seen with the 5-monthly-dose regimen studied in the pivotal clinical trials in premature infants. Specifically, during the fourth and fifth months, 52% and 85%, respectively, would have levels below the lowest concentration (fifth percentile) in those receiving the 5-monthly-dose regimen. Simulations using this model did not support a 3-monthly-dose regimen to protect against severe RSV disease during the typical 5-month season.

Evaluation of persistent pulmonary infiltrates in pediatric oncology patients.

PURPOSE: To evaluate the role of bronchoalveolar lavage (BAL), computed-tomography-guided biopsy (CTB), and open lung biopsy (OLB) in the management of persistent pulmonary infiltrates in pediatric oncology patients. METHODS: Retrospective review of clinical records of pediatric oncology patients who underwent BAL, CTB, and OLB over a 7-year period. Data was compared across the three procedures using chi-square analysis. Logistic regression was used to adjust potential confounding variables for diagnostic yield. RESULTS: There were 113 consecutive patients who underwent 140 separate procedures during their hospitalization. Thirty (26%) patients had a previous BMT. BALs were more likely to occur as the first line of investigation (98% vs. 47%, 45%; P < 0.01) and in patients with diffuse infiltrates (64% vs. 6%, 26%; P < 0.01) when compared to CTB and OLB, respectively. OLBs were performed less frequently in neutropenic patients (26% vs. 53%, 54%; P < 0.05), more often led to change in management directly because of procedure (61% vs. 12%, 33%; P < 0.01), and had higher diagnostic yield (61% vs. 24%, 36%; P < 0.01) when compared to CTB and BAL, respectively. Diagnostic yield of OLB was significantly higher regardless of diffuse or focal nature of infiltrate. Major adverse events after a procedure were not significantly different across the three procedures. Logistic regression demonstrated that having an OLB was independently associated with identifying the cause of pulmonary infiltrate. CONCLUSION: OLB appears to be safe, has the best diagnostic yield, and leads to change in management more often than CTB or BAL in pediatric oncology patients with persistent pulmonary infiltrates.

Measurement of amphotericin B concentration by resonant Raman spectroscopy--a novel technique that may be useful for non-invasive monitoring.

We wished to determine whether Resonant Raman Spectroscopy (RRS) could be used to measure Amphotericin B (AmB) at therapeutic and subtherapeutic concentrations in a model system mimicking the anterior chamber of the eye. The goal was to develop a technique for non-invasive measurement of AmB levels in the aqueous humor (AH) of the eye. A krypton-ion laser source (406.7 nm) was used for excitation and Resonant Raman Spectra were captured with a confocal system in an anterior chamber (AC) model. These spectra were used to develop a correlation curve for prediction of AmB levels. Subsequently, one rabbit was evaluated with this system after 5 days of intravenous AmB administration (1 mg/kg/day) and AmB concentrations measured by RRS were compared to those measured by high-performance liquid chromatography (HPLC). AmB exhibited a unique spectral peak at 1557 cm(-1). Integrated area of this peak linearly correlated with AmB concentration in our model AC. When integrated peak area from multiple in vivo measurements in one animal at steady-state was plotted on this correlation curve, we were able to predict AmB levels. These closely approximated those measured by HPLC. These measurements were not significantly affected by photobleaching or depth profile at acquisition. RRS at 406.7 nm is a method that may be useful for non-invasive monitoring of intraocular AmB levels. This instrument can help physicians decide when repeat, invasive delivery of this drug is warranted based on measurement of actual drug levels in the AH. Also, there is the potential to measure the ocular concentrations of other pharmaceutical agents with similar instruments.

Right atrial mass in a child with disseminated coccidioidomycosis.

A 10-year-old patient with known coccidioidomycosis relapsed and had dysrrhythmias and a right atrial mass. Histopathology and culture after surgical removal revealed that this was a vegetative mass infected with Coccidioides spp. We believe that this is the first case of coccidioidal endocarditis to be reported.