Respiratory Syncytial Virus-Associated Hospitalizations Among Children <5 Years Old: 2016 to 2020

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of hospitalization in US infants. Accurate estimates of severe RSV disease inform policy decisions for RSV prevention.

METHODS

We conducted prospective surveillance for children <5 years old with acute respiratory illness from 2016 to 2020 at 7 pediatric hospitals. We interviewed parents, reviewed medical records, and tested midturbinate nasal ± throat swabs by reverse transcription polymerase chain reaction for RSV and other respiratory viruses. We describe characteristics of children hospitalized with RSV, risk factors for ICU admission, and estimate RSV-associated hospitalization rates.

RESULTS

Among 13 524 acute respiratory illness inpatients <5 years old, 4243 (31.4%) were RSV-positive; 2751 (64.8%) of RSV-positive children had no underlying condition or history of prematurity. The average annual RSV-associated hospitalization rate was 4.0 (95% confidence interval [CI]: 3.8-4.1) per 1000 children <5 years, was highest among children 0 to 2 months old (23.8 [95% CI: 22.5-25.2] per 1000) and decreased with increasing age. Higher RSV-associated hospitalization rates were found in premature versus term children (rate ratio = 1.95 [95% CI: 1.76-2.11]). Risk factors for ICU admission among RSV-positive inpatients included: age 0 to 2 and 3 to 5 months (adjusted odds ratio [aOR] = 1.97 [95% CI: 1.54-2.52] and aOR = 1.56 [95% CI: 1.18-2.06], respectively, compared with 24-59 months), prematurity (aOR = 1.32 [95% CI: 1.08-1.60]) and comorbid conditions (aOR = 1.35 [95% CI: 1.10-1.66]).

CONCLUSIONS

Younger infants and premature children experienced the highest rates of RSV-associated hospitalization and had increased risk of ICU admission. RSV prevention products are needed to reduce RSV-associated morbidity in young infants.

Principal Component Patterns of Pediatric Respiratory Viral Testing Across Health Care Settings

BACKGROUND AND OBJECTIVES

Factors prompting clinicians to request viral testing in children are unclear. We assessed patterns prompting clinicians to perform viral testing in children discharged from an emergency department (ED) or hospitalized with an acute respiratory infection (ARI).

METHODS

Using active ARI surveillance data collected from November 2017 through February 2020, children aged between 30 days and 17 years with fever or respiratory symptoms who had a research respiratory specimen tested were included. Children's presentation patterns from their initial evaluation at each health care setting were analyzed using principal components (PCs) analysis. PC-specific models using logistic regression with robust sandwich estimators were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between PCs and provider-ordered viral testing. PCs were assigned respiratory virus/viruses names a priori based on the patterns represented.

RESULTS

In total, 4107 children were enrolled and tested, with 2616 (64%) discharged from the ED and 1491 (36%) hospitalized. In the ED, children with a coviral presentation pattern had a 1.44-fold (95% CI, 1.24-1.68) increased odds of receiving a provider-ordered viral test than children showing clinical symptoms less representative of coviral-like infection. Whereas children in the ED and hospitalized with rhinovirus-like symptoms had 71% (OR, 0.29; 95% CI, 0.24-0.34) and 39% (OR, 0.61; 95% CI, 0.49-0.76) decreased odds, respectively, of receiving a provider-ordered viral test during their medical encounter.

CONCLUSIONS

Viral tests are frequently ordered by clinicians, but presentation patterns vary by setting and influence the initiation of testing. Additional assessments of factors affecting provider decisions to use viral testing in pediatric ARI management are needed to maximize patient benefits of testing.

Respiratory virus surveillance in hospitalized children less than two-years of age in Kenema, Sierra Leone during the COVID-19 pandemic (October 2020- October 2021)

Globally, viral pathogens are the leading cause of acute respiratory infection in children under-five years. We aim to describe the epidemiology of viral respiratory pathogens in hospitalized children under-two years of age in Eastern Province of Sierra Leone, during the second year of the SARS-CoV-2 pandemic. We conducted a prospective study of children hospitalized with respiratory symptoms between October 2020 and October 2021. We collected demographic and clinical characteristics and calculated each participant´s respiratory symptom severity. Nose and throat swabs were collected at enrollment. Total nucleic acid was purified and tested for multiple respiratory viruses. Statistical analysis was performed using R version 4.2.0 software. 502 children less than two-years of age were enrolled. 376 (74.9%) had at least one respiratory virus detected. The most common viruses isolated were HRV/EV (28.2%), RSV (19.5%) and PIV (13.1%). Influenza and SARS-CoV-2 were identified in only 9.2% and 3.9% of children, respectively. Viral co-detection was common. Human metapneumovirus and RSV had more than two-fold higher odds of requiring O2 therapy while hospitalized. Viral pathogen prevalence was high (74.9%) in our study population. Despite this, 100% of children received antibiotics, underscoring a need to expand laboratory diagnostic capacity and to revisit clinical guidelines implementation in these children. Continuous surveillance and serologic studies among more diverse age groups, with greater geographic breadth, are needed in Sierra Leone to better characterize the long-term impact of COVID-19 on respiratory virus prevalence and to better characterize the seasonality of respiratory viruses in Sierra Leone.

SARS-CoV-2 Testing of Aerosols Emitted During Pediatric Minimally Invasive Surgery: A Prospective, Case-Controlled Study

BACKGROUND

The COVID-19 pandemic has presented significant safety concerns for healthcare providers, especially those performing aerosol-generating procedures. Several surgical societies issued early warnings that aerosols generated during minimally invasive surgery (MIS) could harbor infectious quantities of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This study tested the hypothesis that MIS-aerosols contain SARS-CoV-2.

METHODS

To evaluate SARS-CoV-2 presence in aerosols emitted during intracavitary MIS, children <18 years who required emergent MIS and were discovered to be SARS-CoV-2-positive were enrolled. Swabs were obtained from the port in-line with a filtered smoke evacuation system, the tubing adjacent to this port, the fluid collection chamber and filter, and the distal endotracheal tube (ETT). All swabs were analyzed for SARS-CoV-2 using quantitative reverse-transcription polymerase chain reaction. To evaluate viral distribution in tissues, fluorescence in situ hybridization for SARS-CoV-2 was performed on resected specimens. Outcomes were recorded, and participating healthcare workers were tracked for SARS-CoV-2 conversion.

RESULTS

From July 1, 2020, to June 30, 2021, 11 children requiring emergent MIS were discovered preoperatively to be SARS-CoV-2 positive (median age: 14 years [5-17]). SARS-CoV-2 was detected only in ETT swabs and not in surgical aerosols or specimens. Median operative time was 56.5 minutes (IQR: 46-66), and postoperative stay was 21.2 hours (IQR: 1.97-57.57). No complications or viral eruption were recorded, and none of 63 healthcare workers tested positive for SARS-CoV-2 within 6 weeks.

DISCUSSION

SARS-CoV-2 was detected only in ETT secretions and not in surgical aerosols or specimens among a pediatric cohort of asymptomatic patients having emergent MIS.

Comparison of clinical presentations and burden of respiratory syncytial virus in infants across three distinct healthcare settings in Davidson County, Tennessee

Background

The burden of respiratory syncytial virus (RSV)-associated acute respiratory illnesses among healthy infants (<1 year) in the inpatient setting is well established. The focus on RSV-associated illnesses in the outpatient (OP) and emergency department (ED) settings are however understudied. We sought to determine the spectrum of RSV illnesses in infants at three distinct healthcare settings.

Methods

From 16 December 2019 through 30 April 2020, we performed an active, prospective RSV surveillance study among infants seeking medical attention from an inpatient (IP), ED, or OP clinic. Infants were eligible if they presented with fever and/or respiratory symptoms. Demographics, clinical characteristics, and illness histories were collected during parental/guardian interviews, followed by a medical chart review and illness follow-up surveys. Research nasal swabs were collected and tested for respiratory pathogens for all enrolled infants.

Results

Of the 627 infants screened, 475 were confirmed eligible; 360 were enrolled and research tested. Within this final cohort, 101 (28%) were RSV-positive (IP = 37, ED = 18, and OP = 46). Of the RSV-positive infants, the median age was 4.5 months and 57% had ⩾2 healthcare encounters. The majority of RSV-positive infants were not born premature (88%) nor had underlying medical conditions (92%). RSV-positive infants, however, were more likely to have a lower respiratory tract infection than RSV-negative infants (76% vs 39%, p < 0.001). Hospitalized infants with RSV were younger, 65% required supplemental oxygen, were more likely to have lower respiratory tract symptoms, and more often had shortness of breath and rales/rhonchi than RSV-positive infants in the ED and OP setting.

Conclusion

Infants with RSV illnesses seek healthcare for multiple encounters in various settings and have clinical difference across settings. Prevention measures, especially targeted toward healthy, young infants are needed to effectively reduce RSV-associated healthcare visits.

Metatranscriptomics to characterize respiratory virome, microbiome, and host response directly from clinical samples

We developed a metatranscriptomics method that can simultaneously capture the respiratory virome, microbiome, and host response directly from low biomass samples. Using nasal swab samples, we capture RNA virome with sufficient sequencing depth required to assemble complete genomes. We find a surprisingly high frequency of respiratory syncytial virus (RSV) and coronavirus (CoV) in healthy children, and a high frequency of RSV-A and RSV-B co-detections in children with symptomatic RSV. In addition, we have identified commensal and pathogenic bacteria and fungi at the species level. Functional analysis revealed that H. influenzae was highly active in symptomatic RSV subjects. The host nasal transcriptome reveled upregulation of the innate immune system, anti-viral response and inflammasome pathway, and downregulation of fatty acid pathways in children with symptomatic RSV. Overall, we demonstrate that our method is broadly applicable to infer the transcriptome landscape of an infected system, surveil respiratory infections, and to sequence RNA viruses directly from clinical samples.

Low In-School COVID-19 Transmission and Asymptomatic Infection Despite High Community Prevalence

There is concern that in-person schooling during the coronavirus disease 2019 (COVID-19) pandemic will facilitate disease transmission. Through asymptomatic surveillance and contact tracing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we found low rates of asymptomatic SARS-CoV-2 infection and little in-school transmission of COVID-19 when physical distancing and masking strategies were enforced despite a high community prevalence of COVID-19.

Respiratory Virus Surveillance in Infants across Different Clinical Settings

OBJECTIVES

We aimed to evaluate the distribution, clinical presentations and severity of common acute respiratory infections (ARI) viruses in infants across 3 clinical settings.

STUDY DESIGN

In a prospective virus surveillance study, infants under 1 year with fever and/or respiratory symptoms were enrolled from outpatient, emergency department, and inpatient settings from December 16, 2019 through April 30, 2020. Demographic and clinical characteristics were collected through parent/guardian interviews, medical chart abstractions, and follow-up surveys. Nasal swabs were collected and tested for viruses using quantitative reverse-transcription polymerase chain reaction.

RESULTS

We enrolled 366 infants and tested nasal swabs on 360 (98%); median age was 6.3 months, 50% male. In total, 295 (82%) had at least 1 virus detected; rhinovirus/enterovirus (RV/EV; 42%), respiratory syncytial virus (RSV; 34%), and influenza (15%) were the most common. RSV was the most frequently detected virus in the inpatient (63%) and emergency department (37%) settings, and RV/EV was most frequently detected virus in the outpatient setting (54%). RSV-positive infants had a lower median age (4.9 months) and were more likely to have respiratory distress, and RV/EV-positive infants were less likely to have respiratory distress. Influenza-positive infants had a higher median age (8 months) and were more likely to have systemic symptoms. RSV infection and younger age were associated with higher odds of hospitalization in multivariable logistic regression.

CONCLUSIONS

Across 3 clinical settings, and combining virologic, patient, and health-system information, our results highlight the burden of viral ARI among infants. Overall, RSV, RV/EV, and influenza were most commonly detected, with RSV having the highest disease severity.

Clinical features of parainfluenza infections among young children hospitalized for acute respiratory illness in Amman, Jordan

Background

Parainfluenza virus (PIV) is a leading cause of acute respiratory illness (ARI) in children. However, few studies have characterized the clinical features and outcomes associated with PIV infections among young children in the Middle East.

Methods

We conducted hospital-based surveillance for ARI among children < 2 years of age in a large referral hospital in Amman, Jordan. We systematically collected clinical data and respiratory specimens for pathogen detection using reverse transcription polymerase chain reaction. We compared clinical features of PIV-associated ARI among individual serotypes 1, 2, 3, and 4 and among PIV infections compared with other viral ARI and ARI with no virus detected. We also compared the odds of supplemental oxygen use using logistic regression.

Results

PIV was detected in 221/3168 (7.0%) children hospitalized with ARI. PIV-3 was the most commonly detected serotype (125/221; 57%). Individual clinical features of PIV infections varied little by individual serotype, although admission diagnosis of ‘croup’ was only associated with PIV-1 and PIV-2. Children with PIV-associated ARI had lower frequency of cough (71% vs 83%; p < 0.001) and wheezing (53% vs 60% p < 0.001) than children with ARI associated with other viruses. We did not find a significant difference in supplemental oxygen use between children with PIV-associated infections (adjusted odds ratio [aOR] 1.12, 95% CI 0.66–1.89, p = 0.68) and infections in which no virus was detected.

Conclusions

PIV is frequently associated with ARI requiring hospitalization in young Jordanian children. Substantial overlap in clinical features may preclude distinguishing PIV infections from other viral infections at presentation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06001-1.

Prospective Observational Study to Determine Kinetics of Procalcitonin in Hospitalized Children Receiving Antibiotic Therapy for Non-Critical Acute Bacterial Infections

INTRODUCTION

The kinetics of procalcitonin in pediatric patients with non-critical acute bacterial infections receiving appropriate antibiotic therapy are not well described.

METHODS

We performed a single-center, prospective observational pilot study of children admitted to a tertiary care children's hospital who were receiving antibiotics for treatment of a non-critical acute bacterial infection, and we prospectively measured serial procalcitonin levels daily for 4 days during hospitalization.

RESULTS

Among the 46 children with baseline procalcitonin levels enrolled in the study, procalcitonin kinetics followed a half-life of approximately 24 h in most patients. Procalcitonin declined faster than C-reactive protein over the first 48 h of appropriate antibiotic treatment. There was variation in biomarker levels among participants with the same infection type, especially in participants with bacteremia, musculoskeletal infection and skin/soft tissue infection.

CONCLUSION

Utility of procalcitonin as a biomarker to follow every 24-48 h in non-critically ill children receiving antibiotic therapy for bacterial infections as an objective measure of clinical improvement is promising.

The Changing Landscape of Pediatric Viral Enteropathogens in the Post-Rotavirus Vaccine Era

BACKGROUND

Acute gastroenteritis (AGE) is a common reason for children to receive medical care. However, the viral etiology of AGE illness is not well described in the post-rotavirus vaccine era, particularly in the outpatient (OP) setting.

METHODS

Between 2012 and 2015, children 15 days through 17 years old presenting to Vanderbilt Children's Hospital, Nashville, Tennessee, with AGE were enrolled prospectively from the inpatient, emergency department, and OP settings, and stool specimens were collected. Healthy controls (HCs) were enrolled and frequency matched for period, age group, race, and ethnicity. Stool specimens were tested by means of reverse-transcription real-time quantitative polymerase chain reaction for norovirus, sapovirus, and astrovirus RNA and by Rotaclone enzyme immunoassay for rotavirus antigen, followed by polymerase chain reaction verification of antigen detection.

RESULTS

A total of 3705 AGE case patients and 1563 HCs were enrolled, among whom 2885 case patients (78%) and 1110 HCs (71%) provided stool specimens that were tested. All 4 viruses were more frequently detected in AGE case patients than in HCs (norovirus, 22% vs 8%, respectively; rotavirus, 10% vs 1%; sapovirus, 10% vs 5%; and astrovirus, 5% vs 2%; P < .001 for each virus). In the OP setting, rates of AGE due to norovirus were higher than rate for the other 3 viruses. Children <5 years old had higher OP AGE rates than older children for all viruses.

CONCLUSIONS

Norovirus remains the most common virus detected in all settings, occurring nearly twice as frequently as the next most common pathogens, sapovirus and rotavirus. Combined, norovirus, sapovirus, rotavirus, and astrovirus were associated with almost half of all AGE visits and therefore are an important reason for children to receive medical care.

Pneumonia Severity in Children: Utility of Procalcitonin in Risk Stratification

OBJECTIVES

To determine if serum procalcitonin, an indicator of bacterial etiology in pneumonia in all ages and a predictor of severe pneumonia in adults, is associated with disease severity in children with community-acquired pneumonia.

METHODS

We prospectively enrolled children 2 months to <18 years with clinical and radiographic pneumonia at 2 children's hospitals (2014-2019). Procalcitonin samples were obtained at presentation. An ordinal outcome scale of pneumonia severity was defined: very severe (intubation, shock, or death), severe (intensive care admission without very severe features and/or high-flow nasal cannula), moderate (hospitalization without severe or very severe features), and mild (discharge). Hospital length of stay (LOS) was also examined. Ordinal logistic regression was used to model associations between procalcitonin and outcomes. We estimated adjusted odds ratios (aORs) for a variety of cut points of procalcitonin ranging from 0.25 to 3.5 ng/mL.

RESULTS

The study included 488 children with pneumonia; 30 (6%) were classified as very severe, 106 (22%) as severe, 327 (67%) as moderate, and 25 (5%) as mild. Median procalcitonin in the very severe group was 5.06 (interquartile range [IQR] 0.90-16.83), 0.38 (IQR 0.11-2.11) in the severe group, 0.29 (IQR 0.09-1.90) in the moderate group, and 0.21 (IQR 0.12-1.2) in the mild group. Increasing procalcitonin was associated with increasing severity (range of aORs: 1.03-1.25) and increased LOS (range of aORs: 1.04-1.36). All comparisons were statistically significant.

CONCLUSIONS

Higher procalcitonin was associated with increased severity and LOS. Procalcitonin may be useful in helping clinicians evaluate pneumonia severity.

1406. Comparison of Clinical Presentations and Burden of Respiratory Syncytial Virus in Infants Across Three Distinct Healthcare Settings

Background

Respiratory syncytial virus (RSV) accounts for the majority of lower respiratory tract illnesses in hospitalized infants. In the U.S., RSV hospitalizations are well characterized; yet, emergency department (ED) and outpatient (OP) visits are underrecognized. We evaluated the burden of RSV across three distinct healthcare settings during one respiratory season.

Methods

From 12/16/19-4/30/20, we conducted a prospective RSV surveillance study among Davidson County, TN infants under one year who presented to an inpatient (IP), ED, or one of four OP clinics with either fever or any upper respiratory (i.e., cough, earache, nasal congestion, rhinorrhea, sore throat) and/or lower respiratory [i.e., wheezing, crackles, rales, diminished breath sounds, shortness of breath (SOB)] symptoms. Demographic and illness history were collected during parental/guardian interviews, followed by medical chart abstraction. Nasal swabs were collected and tested for RSV using Luminex® NxTAG RPP. Due to the COVID-19 pandemic, on 3/16/20 enrollment at three of the four OP clinics ceased.

Results

A total of 627 infants were screened, of whom 473 (75%) were confirmed eligible, 364 (77%) enrolled, 361 (99%) were tested for RSV of which 101 (28%) were RSV+ (IP=37, ED=18, OP=46) (Figure 1). Compared to RSV-negative subjects, RSV+ subjects were younger (6.6 vs. 4.9 months, p< 0.001), 56% were male and 48% white. By setting, infants in the OP setting were older than those seen in the IP and ED [(p=0.002), Figure 2]. Compared to infants in the OP setting, hospitalized infants were more likely to present with SOB and rhonchi/rales, but less likely to have only upper respiratory symptoms (Figure 3) and be African American (p=0.046). Infants in the IP setting had a higher proportion of clinical RSV diagnostic testing (73%) compared to the ED (39%) and OP (28%) settings (p< 0.001).

Figure 1. Davidson County Infants with RSV by MMWR Week and Healthcare Setting (n=101)

Figure 2. Cumulative Enrollment of Davidson County Infants with RSV by Age in Months and Healthcare Setting (n=101)

Figure 3. Proportion of Davidson County Infants with RSV Showing each Clinical Symptom, by Healthcare Setting

Conclusion

Two-thirds of RSV+ infants sought care from either an OP or ED setting, with nearly all hospitalized infants presenting with both upper and lower respiratory symptoms. The underutilization of diagnostic testing in the OP settings may underestimate the true burden of RSV. Future studies are essential to document the true prevalence of RSV in order to assess the need and impact of new interventions (e.g., immunizations, antivirals).

Disclosures

Danielle A. Rankin, MPH, CIC, Sanofi Pasteur (Grant/Research Support, Research Grant or Support) Zaid Haddadin, MD, CDC (Grant/Research Support, Research Grant or Support)Quidel Corporation (Grant/Research Support, Research Grant or Support)sanofi pasteur (Grant/Research Support, Research Grant or Support) Jon Fryzek, PhD, MPH, EpidStrategies (Employee) Mina Suh, MPH, International Health, EpidStrategies (Employee) Donald S. Shepard, PhD, Sanofi Pasteur (Grant/Research Support) Natasha B. Halasa, MD, MPH, Genentech (Other Financial or Material Support, I receive an honorarium for lectures - it’s a education grant, supported by genetech)Karius (Consultant)Moderna (Consultant)Quidel (Grant/Research Support, Research Grant or Support)Sanofi (Grant/Research Support, Research Grant or Support)

1507. Clinical Characteristics of Common Respiratory Viruses Detected in Infants Across Different Clinical Settings

Background

Viral acute respiratory infections (ARI) continues to be a significant cause of healthcare visits in young children. We evaluated the clinical presentation and disease severity of common respiratory viruses associated with medically attended ARI in infants.

Methods

We conducted a prospective viral surveillance study in Davidson County, TN. Infants under one year with fever and/or respiratory symptoms were enrolled from the outpatient (OP), emergency department (ED), or inpatient (IP) settings from 12/16/2019 through 4/30/2020. Nasal swabs were collected and tested for common viral pathogens using Luminex® NxTAG Respiratory Pathogen Panel. Demographic and clinical characteristics were collected through parent/guardian interviews and medical chart abstractions.

Results

In total, 364 participants were enrolled, and 361 (99%) had nasal swabs collected and tested. Overall, mean age was 6±3.3 months, 50% were female, 45% White, and 27% Hispanic. Of the 295 (82%) virus-positive specimens; the three most common viruses were rhinovirus/enterovirus (RV/EV), respiratory syncytial virus (RSV), and influenza (flu) [124, 101, and 44, respectively]. Compared to virus-negative infants, virus-positive infants were more likely to have more severe ARI symptoms and to be admitted to the intensive care unit (Table 1). Compared to other virus-positive infants: RV/EV-positive infants were more likely to be White, attend daycare, but less likely to present with respiratory distress, or require oxygen or admission; flu-positive infants were older and more likely to have systemic symptoms rather than ARI symptoms, and RSV-positive infants were more likely to present with respiratory distress, receive oxygen and be hospitalized (Table 1).

Table 1. Demographic and Clinical Characteristics of Study Subjects

Conclusion

The majority of ARI in infants are due to respiratory viruses, with RSV, RV/EV, and flu accounting for over three-quarters of these viruses. The clinical presentations and disease severity differed across the clinical settings and the three main viruses, with RSV being most severe. To decrease the burden of medically attended viral ARI, preventive measures (i.e., developing new vaccines and antivirals), refining current vaccination strategies, and infection control measures are needed.

Disclosures

Zaid Haddadin, MD, CDC (Grant/Research Support, Research Grant or Support)Quidel Corporation (Grant/Research Support, Research Grant or Support)sanofi pasteur (Grant/Research Support, Research Grant or Support) Danielle A. Rankin, MPH, CIC, Sanofi Pasteur (Grant/Research Support, Research Grant or Support) Jon Fryzek, PhD, MPH, EpidStrategies (Employee) Mina Suh, MPH, International Health, EpidStrategies (Employee) Donald S. Shepard, PhD, Sanofi Pasteur (Grant/Research Support) Natasha B. Halasa, MD, MPH, Genentech (Other Financial or Material Support, I receive an honorarium for lectures - it’s a education grant, supported by genetech)Karius (Consultant)Moderna (Consultant)Quidel (Grant/Research Support, Research Grant or Support)Sanofi (Grant/Research Support, Research Grant or Support)

685. Comparison of Singleplex qPCR and the Luminex MAGPIX Platform for the Detection of Viral Pathogens

Background

Various respiratory molecular assays are available, each with different characteristics and advantages that make them uniquely valuable. The objective of this study was to compare rates of viral detection using singleplex and multiplex platforms in a research setting.

Methods

A prospective viral surveillance study was conducted in Davidson County, TN. Infants under one year who presented with fever and/or respiratory symptoms were enrolled from the outpatient, emergency department and inpatient settings. Nasal swabs were collected and tested for influenza A (FluA), influenza B (FluB), human metapneumovirus (MPV), respiratory syncytial virus A and B (RSVA and RSVB), human adenovirus (AdV), parainfluenza 1, 2, 3, and 4 (PIV1-4) and SARS-2-CoV by both singleplex qPCR and the Luminex NxTAG Respiratory Pathogen and NxTAG CoV Extended panels. The rhinovirus/enterovirus, human bocavirus, Chlamydophila pneumoniae, Mycoplasma pneumoniae and coronavirus HKU1, NL63, 229E and OC43 results from the Luminex panel were excluded because singleplex qPCR was not performed on those targets. For singleplex qPCR results, cycle threshold (Ct) values were used as a surrogate for viral load, with a higher Ct value indicating a lower viral load.

Results

A total of 112 nasal specimens were tested by both singleplex qPCR and Luminex, of which 65 were positive for at least one virus by either platform and 56 had a virus detected on both platforms (Figure 1). Seven specimens were positive by singleplex qPCR only and two were positive by Luminex only (Figure 1). The targets positive by singleplex qPCR only included FluB, RSVA, AdV and PIV2 and those positive by Luminex only included FluA H1N1 and RSVB (Figure 2). Specimens that were positive only on the singleplex assay had a higher average Ct value than those that were positive on both assays, indicating a lower viral load (Figure 3).

Figure 1

Conclusion

The multiplex assay identified 89% of the total viruses detected while singleplex qPCR identified 97% of the total viruses detected. Lower viral loads may contribute to false negative results on the multiplex platforms. Future studies with larger sample sizes are needed in order validate our findings.

Disclosures

Erin Yepsen, BS, Sanofi Pasteur (Grant/Research Support, Research Grant or Support) Zaid Haddadin, MD, CDC (Grant/Research Support, Research Grant or Support)Quidel Corporation (Grant/Research Support, Research Grant or Support)sanofi pasteur (Grant/Research Support, Research Grant or Support) Danielle A. Rankin, MPH, CIC, Sanofi Pasteur (Grant/Research Support, Research Grant or Support) Natasha B. Halasa, MD, MPH, Genentech (Other Financial or Material Support, I receive an honorarium for lectures - it’s a education grant, supported by genetech)Karius (Consultant)Moderna (Consultant)Quidel (Grant/Research Support, Research Grant or Support)Sanofi (Grant/Research Support, Research Grant or Support)

913. Distribution of Respiratory Viral Pathogens in Infants Across Different Clinical Settings from December 2019 to April 2020

Background

Acute respiratory infections (ARI) are a major cause of morbidity and mortality in young children, with viral pathogens being the most common etiologies. However, due to limited and inconsistent clinical diagnostic viral testing in the outpatient (OP) setting compared to the inpatient (IP) setting, the actual burden and distribution of viral pathogens across these clinical settings remain largely underreported. We aimed to evaluate the frequency of common respiratory viruses in medically attended ARI in infants.

Methods

We conducted a prospective viral surveillance study in Davidson County, TN. Eligible infants under one year presenting with fever and/or respiratory symptoms were enrolled from OP, emergency department (ED), or IP settings. Nasal swabs were collected and tested for common viral pathogens using Luminex® NxTAG Respiratory Pathogen Panel and for SARS-CoV-2 using Luminex® NxTAG CoV extended panel.

Results

From 12/16/2019 to 4/30/2020, 364 infants were enrolled, and 361 (99%) had nasal swabs collected and tested. Of those, 295 (82%) had at least one virus detected; rhinovirus/enterovirus (RV/EV) [124 (42%)], respiratory syncytial virus (RSV) [101 (32%)], and influenza (flu) [44 (15%)] were the three most common pathogens detected. No samples tested positive for SARS-CoV-2. Overall, the mean age was 6.1 months, 50% were male, 45% White and 27% Hispanic. Figure 1 shows the total number of PCR viral testing results by month. RSV was the most frequent virus detected in the IP (63%) and ED (37%) settings, while RV/EV was the most common in the OP setting (Figure 2). Figure 3 displays viral seasonality by clinical setting, showing an abrupt decrease in virus-positive cases following the implementation of a stay-at-home order on March 23, 2020 in Nashville, TN.

Distribution of Respiratory Viruses in Different Settings

Distribution of Respiratory Viruses in Different Settings by Season

Conclusion

Most medical encounters in infants are due to viral pathogens, with RSV, RV/EV, and flu being the most common. However, distributions differed by clinical setting, with RSV being the most frequently detected in the IP and ED settings, and second to RV/EV in the OP setting. Continued active viral ARI surveillance in various clinical settings is warranted. Preventative measures such as vaccines and infection control measures deserve study to reduce viral ARI burden.

Disclosures

Zaid Haddadin, MD, CDC (Grant/Research Support, Research Grant or Support)Quidel Corporation (Grant/Research Support, Research Grant or Support)sanofi pasteur (Grant/Research Support, Research Grant or Support) Danielle A. Rankin, MPH, CIC, Sanofi Pasteur (Grant/Research Support, Research Grant or Support) Jon Fryzek, PhD, MPH, EpidStrategies (Employee) Mina Suh, MPH, International Health, EpidStrategies (Employee) Donald S. Shepard, PhD, Sanofi Pasteur (Grant/Research Support) Natasha B. Halasa, MD, MPH, Genentech (Other Financial or Material Support, I receive an honorarium for lectures - it’s a education grant, supported by genetech)Karius (Consultant)Moderna (Consultant)Quidel (Grant/Research Support, Research Grant or Support)Sanofi (Grant/Research Support, Research Grant or Support)

Infectious Causes of Acute Gastroenteritis in US Children Undergoing Allogeneic Hematopoietic Cell Transplant: A Longitudinal, Multicenter Study

BACKGROUND

Acute gastroenteritis (AGE) in hematopoietic cell transplant (HCT) patients causes significant morbidity and mortality. Data regarding the longitudinal assessment of infectious pathogens during symptomatic AGE and asymptomatic periods, particularly in children, are limited. We investigated the prevalence of AGE-associated infectious pathogens in children undergoing allogeneic HCT.

METHODS

From March 2015 through May 2016, 31 pediatric patients at 4 US children's hospitals were enrolled and had stool collected weekly from pre-HCT through 100 days post-HCT for infectious AGE pathogens by molecular testing. Demographics, clinical symptoms, antimicrobials, vaccination history, and outcomes were manually abstracted from the medical record into a standardized case report form.

RESULTS

We identified a pathogen in 18% (38/206) of samples, with many detections occurring during asymptomatic periods. Clostridioides difficile was the most commonly detected pathogen in 39% (15/38) of positive specimens, although only 20% (3/15) of C. difficile-positive specimens were obtained from children with diarrhea. Detection of sapovirus, in 21% (8/38) of pathogen-positive specimens, was commonly associated with AGE, with 87.5% of specimens obtained during symptomatic periods. Norovirus was not detected, and rotavirus was detected infrequently. Prolonged shedding of infectious pathogens was rare.

CONCLUSIONS

This multicenter, prospective, longitudinal study suggests that the epidemiology of AGE pathogens identified from allogeneic HCT patients may be changing. Previously reported viruses, such as rotavirus and norovirus, may be less common due to widespread vaccination and institution of infection control precautions, and emerging viruses such as sapoviruses may be increasingly recognized due to the use of molecular diagnostics.

Agreement Between Two Procalcitonin Assays in Hospitalized Children

Introduction

Agreement between available procalcitonin (PCT) assays is unclear. We sought to compare concordance between Roche and bioMérieux PCT assays using pediatric samples.

Methods

We evaluated 213 plasma samples from 208 children. We tested each sample on both the Roche and bioMérieux PCT platforms.

Results

At ranges < 2 μg/L, the Roche platform had a mean negative bias of 0.13 μg/L versus the bioMérieux platform. This bias resulted in PCT levels that crossed accepted cut points in 12.7% of patients.

Conclusions

PCT levels measured on either platform are similar, especially at PCT ranges used for antibiotic decision-making algorithms.

Funding

This work was supported by an investigator-initiated research agreement through bioMérieux and by the National Institute of Allergy and Infectious Diseases Childhood Infection Research Program (ChIRP), National Institute of Health and the National Center for Advancing Translational Sciences of the National Institute of Health.

Multiple Introductions and Antigenic Mismatch with Vaccines May Contribute to Increased Predominance of G12P[8] Rotaviruses in the United States

Rotavirus is the leading global cause of diarrheal mortality for unvaccinated children under 5 years of age. The outer capsid of rotavirus virions consists of VP7 and VP4 proteins, which determine viral G and P types, respectively, and are primary targets of neutralizing antibodies. Successful vaccination depends upon generating broadly protective immune responses following exposure to rotaviruses presenting a limited number of G- and P-type antigens. Vaccine introduction resulted in decreased rotavirus disease burden but also coincided with the emergence of uncommon G and P genotypes, including G12. To gain insight into the recent predominance of G12P[8] rotaviruses in the United States, we evaluated 142 complete rotavirus genome sequences and metadata from 151 clinical specimens collected in Nashville, TN, from 2011 to 2013 through the New Vaccine Surveillance Network. Circulating G12P[8] strains were found to share many segments with other locally circulating strains but to have distinct constellations. Phylogenetic analyses of G12 sequences and their geographic sources provided evidence for multiple separate introductions of G12 segments into Nashville, TN. Antigenic epitopes of VP7 proteins of G12P[8] strains circulating in Nashville, TN, differ markedly from those of vaccine strains. Fully vaccinated children were found to be infected with G12P[8] strains more frequently than with other rotavirus genotypes. Multiple introductions and significant antigenic mismatch may in part explain the recent predominance of G12P[8] strains in the United States and emphasize the need for continued monitoring of rotavirus vaccine efficacy against emerging rotavirus genotypes.IMPORTANCE Rotavirus is an important cause of childhood diarrheal disease worldwide. Two immunodominant proteins of rotavirus, VP7 and VP4, determine G and P genotypes, respectively. Recently, G12P[8] rotaviruses have become increasingly predominant. By analyzing rotavirus genome sequences from stool specimens obtained in Nashville, TN, from 2011 to 2013 and globally circulating rotaviruses, we found evidence of multiple introductions of G12 genes into the area. Based on sequence polymorphisms, VP7 proteins of these viruses are predicted to present themselves to the immune system very differently than those of vaccine strains. Many of the sick children with G12P[8] rotavirus in their diarrheal stools also were fully vaccinated. Our findings emphasize the need for continued monitoring of circulating rotaviruses and the effectiveness of the vaccines against strains with emerging G and P genotypes.

Intestinal Carriage of Third-Generation Cephalosporin-Resistant and Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Healthy US Children

BACKGROUND

The epidemiology of antibiotic-resistant Enterobacteriaceae intestinal carriage in healthy US children has not been well characterized.

METHODS

Children between 14 days and 14 years of age were enrolled during well-child visits in Oakland, California, Kansas City, Kansas, and Nashville, Tennessee, between December 2013 and March 2015. Data on recent antibiotic use by the child and travel and hospitalization history of all members of each child's household were obtained with a risk-factor survey. Stool specimens collected from the subjects were screened for extended-spectrum β-lactamase-producing (ESBL-P) bacteria using CHROMagar ESBL medium. Putative ESBL-P Escherichia coli and Klebsiella colonies underwent phenotypic confirmation by double-disk synergy testing; confirmed third-generation cephalosporin-resistant (3GCR) isolates underwent additional antibiotic-susceptibility testing.

RESULTS

In 519 subjects, the overall 3GCR Enterobacteriaceae carriage rate was 4.4% (n = 23) and ranged from 3.4% to 5.1% among the study sites. The ESBL-P Enterobacteriaceae carriage rate was 3.5% (n = 18). The rates of 3GCR Enterobacteriaceae carriage was highest in 1 to <2 year olds at 6.5%, and was 5.2% in <5 year-olds vs 1.7% in ≥5-year-olds (P = .11). 3GCR and ESBL-P Enterobacteriaceae carriage was associated with international travel within the previous year; 11.1% of ESBL-P Enterobacteriaceae carriers reported this history compared with 1.6% of noncarriers (P = .004). No other queried factor was found to increase risk. Of the 24 analyzed 3GCR isolates, 58% were multidrug resistant.

CONCLUSIONS

The 3GCR Enterobacteriaceae carriage rate exceeds 5% in healthy US children <5 years of age. International travel within the previous year increased the risk of 3GCR and ESBL-P Enterobacteriaceae carriage. In contrast, we found no differences in the rates of hospitalization or recent antibiotic exposure between carriers and noncarriers. Young children, who have the highest prevalence of colonization, might be a sentinel population to study to gain a better understanding of community sources of antibiotic-resistant Enterobacteriaceae.

Analysis of hospitalizations comparing rifaximin versus lactulose in the management of hepatic encephalopathy

INTRODUCTION

Patients with end-stage liver disease often develop hepatic encephalopathy. The loss in cognitive abilities results in marked economic loss to the patient and health care community. We report hospital admission rates and economic impact of patients with end-stage liver disease suffering from hepatic encephalopathy.

METHODS

The medical records were reviewed involving liver transplant patients started on lactulose or rifaximin therapy after presenting with stage 2 hepatic encephalopathy from January 2004 to November 2005. Information collected included demographics, hospitalizations required for hepatic encephalopathy, economic data, and Model for End-stage Liver Disease (MELD) score.

RESULTS

Thirty-nine patients met study criteria: 24 patients treated with lactulose (group one) and 15 with rifaximin (group two). Group one included 18 men and six women of mean age 48 (range 39 to 58), average MELD 14 (range 10 to 19). Group two included 10 men and five women of mean age 47 (range 42 to 58), average MELD 15 (range 10 to 19). Group one patients required 19 hospitalizations overall: three patients with three hospitalizations, four patients with two hospitalizations, and two patients required one hospitalization. Total drug cost per month was 50 dollars(group one) and 620 dollars(group two). The average annual cost of hospitalization, emergency room visit, and drug per patient treated was 13,284.96 dollars for a total of 318,839 dollars (range 5005 dollars to 26,255 dollars, including drug cost and hospital care). Group two required three hospitalizations, all three with one visit. The average annual cost of hospitalization, emergency room visit, and drug per patient treated was 7958.13 dollars for a total of 119,372 dollars (range 6005 dollars to 19,255 dollars, including drug cost and hospital care). The total cost of therapy per patient per year was 13,285 dollars (group one) versus 7958 dollars (group two). The average length of stay was shorter in group two [3.5 days (range 3 to 4)] versus group 1 [5.0 days (range 3 to 10); P < .0001].

CONCLUSION

These pilot data demonstrate the marked difference in economic costs for the treatment of hepatic encephalopathy. The results also show that in comparative groups, the economic gains are quickly lost when using lactulose.

Minor papilla cannulation and dorsal ductography in pancreas divisum

Until recently, pancreas divisum represented a major technical barrier to a complete evaluation of pancreatic ductal anatomy. Technical refinements have now made it possible to achieve minor papilla cannulation and dorsal ductography in more than 90% of attempts. In 120 consecutive dorsal ductograms, structural pathology was demonstrated in 36 subjects (30%): chronic pancreatitis in 23, pancreatic stones in 10, pseudocyst(s) in 4, ductal "cut-off" in 7, pancreatic cancer in 3, and partial agenesis in 1 (some patients had more than one finding). For patients in whom alcohol abuse was excluded, ductal pathology was present in 25%. Abnormal ventral ductograms were present in only 8% of cases, demonstrating that dorsal ductography has an appreciable additional diagnostic yield. When the clinical situation indicates the need for pancreatography, minor papilla cannulation should be performed if major papilla cannulation fails or reveals only the ventral pancreatogram of pancreas divisum.

Comparison of three nonsurgical treatments for bleeding esophageal varices

Ninety-seven patients with recent or active variceal bleeding were randomly assigned to oral propranolol, endoscopic sclerotherapy plus oral propranolol, or transhepatic sclerotherapy plus oral propranolol. The effects of treatment on the number of units transfused, rebleeding of any magnitude, major rebleeding, and death were assessed in these patients, 82% of whom were alcoholic and 81% Child's Class C. After a minimum follow-up interval of 2 yr (range, 27-65 mo), major rebleeding rates were 65% for propranolol alone, 45% for endoscopic sclerotherapy plus propranolol, and 60% for transhepatic sclerotherapy plus propranolol. The corresponding death rates were 81% for propranolol alone, 55% for endoscopic sclerotherapy plus propranolol, and 66% for transhepatic sclerotherapy plus propranolol (p = 0.03). Thirty-three patients (34%) never received propranolol; 8 due to medical contraindications and 25 because they died or bled enough to meet the definition of treatment failure within 3 or 4 days of randomizations (no significant differences among treatment groups). Patients assigned to propranolol alone bled sooner, bled more units, and had a higher mortality rate than patients treated by endoscopic sclerotherapy plus propranolol. Patients treated with transhepatic sclerotherapy plus propranolol had intermediate results. Propranolol alone is inadequate treatment for esophageal variceal bleeding in patients with advanced liver disease.

Oral medications for upper gastrointestinal endoscopy using a small diameter endoscope

We carried out a double-blinded, randomized prospective study to compare patient tolerance of small diameter endoscopes using limited potency oral premedication to complement topical anesthesia. Patients randomly received either oral placebo, diphenhydramine (100 mg), acetaminophen (1000 mg), or both drugs 30 to 60 min prior to endoscopy. All patients received topical Cetacaine and underwent upper endoscopy with the Olympus XP10 7.9-mm fiberscope. The combination of acetaminophen (1000 mg) and diphenhydramine (100 mg) significantly improved tolerance over topical anesthetic alone. Obvious sedation from the medications was infrequent. Gag response after a topical anesthesia was a significant predictor of patient tolerance. We conclude that small diameter endoscopes are well tolerated for diagnostic upper endoscopy. Oral premedications additionally improve tolerance slightly.

The yield of routine duodenal aspiration for Giardia lamblia during esophagogastroduodenoscopy

Giardia lamblia, the most common intestinal parasite in the United States, may present with nonspecific gastrointestinal symptoms when the infection is chronic. In order to determine how frequently the parasite could be detected in patients undergoing endoscopy for standard indications, duodenal aspirates were collected from 144 patients. Despite G. lamblia being endemic in the state (and therefore readily recognized in our laboratory), there was only one positive aspirate in the 144 specimens collected (0.7%) at this midwestern, tertiary care facility servicing a primarily middle class population. In the population sampled, routine duodenal aspiration for G. lamblia in patients not clinically suspected of having this parasitic infection is of very low yield.

Physicians' estimates of the probability of myocardial infarction in emergency room patients with chest pain

To evaluate the ability of emergency room physicians to estimate the probability of myocardial infarction in patients with acute chest pain, the authors gathered historical, physical, and electrocardiographic information from 492 patients at the time of their presentation. The physicians admitted 30% of them to intensive care: 53 of the 61 patients with infarctions (sensitivity = 87%) and 96 of the 431 without infarctions (specificity = 78%). Overall, 36% of those admitted had infarctions. The physicians' numeric estimate of the probability of infarction was a good univariate discriminator of infarction, as demonstrated by Receiver Operator Characteristics analysis, and, as indicated by their actual operating point, they seemed to maximize the accuracy of patient classification rather than sensitivity or specificity. Logistic regression analysis identified the physicians' probability estimate as the strongest multivariate predictor of infarction, considering all other clinical information available.

Predictors of myocardial infarction in emergency room patients

To develop a decision rule to aid in the diagnosis of myocardial infarction, we evaluated clinical and ECG data on 540 adults treated in an urban hospital emergency room for acute chest pain. Of 62 (11.5%) patients who had acute infarctions, 54 were admitted to intensive care (sensitivity 87%); 103 of 478 patients without infarctions were also admitted to intensive care (specificity 78%). Thirty-four percent of all patients admitted had infarctions. Multivariate analysis identified only four clinical variables which carried independent information predicting infarction: two from the ECG and two from the clinical history. A predictive model based on these four variables had significantly greater specificity (86% vs. 78%, p = .003) and accuracy of overall patient classification (88% vs. 79%, p = .013) but somewhat lower sensitivity (81% vs. 87%, p = .46) than physician judgments. However, a decision rule which would have admitted to intensive care those patients with a high probability of infarction who were not admitted by the emergency room physicians, would have increased the sensitivity for detecting infarction to 95% with no appreciable decrease in specificity or yield of infarctions among patients admitted to intensive care.