Enterovirus D68 in Hospitalized Children: Sequence Variation, Viral Loads and Clinical Outcomes

Clinical and molecular characteristics of the 2022 Enterovirus-D68 outbreak among hospitalized children, Ohio, USA

BACKGROUND

Enterovirus-D68 (EV-D68) has appeared biennially in the United States following the 2014 outbreak. It has gained epidemiologic and clinical relevance and was identified as an important pathogen associated with severe respiratory and central nervous system diseases. We aim to describe the clinical and molecular characteristics of the post-pandemic 2022 Enterovirus-D68 outbreak in children evaluated in a tertiary pediatric hospital in Columbus, Ohio.

METHODS

EV-D68 RT-PCR was performed on nasopharyngeal specimens collected during Jun-Nov 2022 from children (<18 years), identified by 1) physician-order or 2) random selection of 10-15 specimens weekly that were Rhinovirus/Enterovirus-positive by physician-ordered respiratory virus panel. Patients who tested positive for EV-D68 were identified and clinical data and outcomes were analyzed. Partial viral VP1 region was sequenced and characterized.

RESULTS

Forty-four children positive for EV-D68 were identified, among which 88.6 % of patients presented with respiratory symptoms and 61.4 % required PICU admission. Two patients presented with AFM that was attributed to EV-D68. EV-D68 sequences from 2022 clustered within the B3 subclade.

CONCLUSIONS

A significant proportion of children identified with EV-D68 during the 2022 outbreak had respiratory compromise requiring PICU admission. As the virus continues evolving, it is important to monitor the activity of EV-D68, characterizing these strains clinically and genetically, which will help to understand the viral pathogenicity and virulence.

Global prevalence and case fatality rate of Enterovirus D68 infections, a systematic review and meta-analysis

A substantial amount of epidemiological data has been reported on Enterovirus D68 (EV-D68) infections after the 2014 outbreak. Our goal was to map the case fatality rate (CFR) and prevalence of current and past EV-D68 infections. We conducted a systematic review (PROSPERO, CRD42021229255) with published articles on EV-68 infections in PubMed, Embase, Web of Science and Global Index Medicus up to January 2021. We determined prevalences using a model random effect. Of the 4,329 articles retrieved from the databases, 89 studies that met the inclusion criteria were from 39 different countries with apparently healthy individuals and patients with acute respiratory infections, acute flaccid myelitis and asthma-related diseases. The CFR estimate revealed occasional deaths (7/1353) related to EV-D68 infections in patients with severe acute respiratory infections. Analyses showed that the combined prevalence of current and past EV-D68 infections was 4% (95% CI = 3.1-5.0) and 66.3% (95% CI = 40.0-88.2), respectively. The highest prevalences were in hospital outbreaks, developed countries, children under 5, after 2014, and in patients with acute flaccid myelitis and asthma-related diseases. The present study shows sporadic deaths linked to severe respiratory EV-D68 infections. The study also highlights a low prevalence of current EV-D68 infections as opposed to the existence of EV-D68 antibodies in almost all participants of the included studies. These findings therefore highlight the need to implement and/or strengthen continuous surveillance of EV-D68 infections in hospitals and in the community for the anticipation of the response to future epidemics.

Viral Loads and Disease Severity in Children with Rhinovirus-Associated Illnesses

The role of rhinoviruses (RVs) in children with clinical syndromes not classically associated with RV infections is not well understood. We analyzed a cohort of children ≤21 years old who were PCR+ for RV at a large Pediatric Hospital from 2011 to 2013. Using univariate and multivariable logistic regression, we analyzed the associations between demographic, clinical characteristics, microbiology data, and clinical outcomes in children with compatible symptoms and incidental RV detection. Of the 2473 children (inpatients and outpatients) with an RV+ PCR, 2382 (96%) had compatible symptoms, and 91 (4%) did not. The overall median age was 14 months and 78% had underlying comorbidities. No differences in RV viral loads were found according to the presence of compatible symptoms, while in children with classic RV symptoms, RV viral loads were higher in single RV infections versus RV viral co-infections. Bacterial co-infections were more common in RV incidental detection (7.6%) than in children with compatible symptoms (1.9%, p < 0.001). The presence of compatible symptoms independently increased the odds ratio (OR, 95% CI) of hospitalization 4.8 (3.1-7.4), prolonged hospital stays 1.9 (1.1-3.1), need for oxygen 12 (5.8-25.0) and pediatric intensive care unit (PICU) admission 4.13 (2.0-8.2). Thus, despite comparable RV loads, disease severity was significantly worse in children with compatible symptoms.

Enterovirus D68 outbreak detection through a syndromic disease epidemiology network

BACKGROUND

In 2014, enterovirus D68 (EV-D68) was responsible for an outbreak of severe respiratory illness in children, with 1,153 EV-D68 cases reported across 49 states. Despite this, there is no commercial assay for its detection in routine clinical care. BioFire® Syndromic Trends (Trend) is an epidemiological network that collects, in near real-time, deidentified. BioFire test results worldwide, including data from the BioFire® Respiratory Panel (RP).

OBJECTIVES

Using the RP version 1.7 (which was not explicitly designed to differentiate EV-D68 from other picornaviruses), we formulate a model, Pathogen Extended Resolution (PER), to distinguish EV-D68 from other human rhinoviruses/enteroviruses (RV/EV) tested for in the panel. Using PER in conjunction with Trend, we survey for historical evidence of EVD68 positivity and demonstrate a method for prospective real-time outbreak monitoring within the network.

STUDY DESIGN

PER incorporates real-time polymerase chain reaction metrics from the RPRV/EV assays. Six institutions in the United States and Europe contributed to the model creation, providing data from 1,619 samples spanning two years, confirmed by EV-D68 gold-standard molecular methods. We estimate outbreak periods by applying PER to over 600,000 historical Trend RP tests since 2014. Additionally, we used PER as a prospective monitoring tool during the 2018 outbreak.

RESULTS

The final PER algorithm demonstrated an overall sensitivity and specificity of 87.1% and 86.1%, respectively, among the gold-standard dataset. During the 2018 outbreak monitoring period, PER alerted the research network of EV-D68 emergence in July. One of the first sites to experience a significant increase, Nationwide Children's Hospital, confirmed the outbreak and implemented EV-D68 testing at the institution in response. Applying PER to the historical Trend dataset to determine rates among RP tests, we find three potential outbreaks with predicted regional EV-D68 rates as high as 37% in 2014, 16% in 2016, and 29% in 2018.

CONCLUSIONS

Using PER within the Trend network was shown to both accurately predict outbreaks of EV-D68 and to provide timely notifications of its circulation to participating clinical laboratories.

Molecular and Clinical Comparison of Enterovirus D68 Outbreaks among Hospitalized Children, Ohio, USA, 2014 and 2018

Enterovirus D68 (EV-D68) causes respiratory tract infections and neurologic manifestations. We compared the clinical manifestations from 2 EV-D68 outbreaks in 2014 and 2018 and a low-activity period in 2016 among hospitalized children in central Ohio, USA, and used PCR and sequencing to enable phylogenetic comparisons. During both outbreak periods, infected children had respiratory manifestations that led to an increase in hospital admissions for asthma. The 2018 EV-D68 outbreak appeared to be milder in terms of respiratory illness, as shown by lower rates of pediatric intensive care unit admission. However, the frequency of severe neurologic manifestations was higher in 2018 than in 2014. During the same period in 2016, we noted neither an increase in EV-D68 nor a significant increase in asthma-related admissions. Phylogenetic analyses showed that EV-D68 isolates from 2018 clustered differently within clade B than did isolates from 2014 and are perhaps associated with a different EV-D68 subclade.

Enterovirus D68 Causing Acute Respiratory Infection: Clinical Characteristics and Differences With Acute Respiratory Infections Associated With Enterovirus Non-D68

BACKGROUND

Enterovirus (EV) D68 is mainly associated with acute respiratory infection (ARI). Since 2014, when outbreaks in different countries were observed, this emerging virus was considered a potential threat to public health.

METHODS

During 2015-2017, the presence of enterovirus RNA was investigated in all respiratory samples of children younger than 15 years of age with ARI, obtained for virologic studies in the Pediatric Emergency Care Units and wards of 2 hospitals in Gipuzkoa (Spain), using a commercial multiplex real-time polymerase chain reaction. When enterovirus was detected, a polymerase chain reaction to amplify a specific viral polyprotein (VP1) gene region of EV-D68 was performed.

RESULTS

In 2016, EV-D68 circulation was associated to ARI, with the highest incidence in the spring months. EV-D68 was detected in 44 children, mean age 30.1 ± 31.7 months old, 23 (52.3%) of them females and 17 (38.6%) with underlying respiratory medical conditions. Thirty-two patients (72%) required hospital admission, receiving the discharge diagnosis of recurrent wheezing (37.5%), asthmatic crisis (37.5%) or bronchiolitis (12.5%). Seven children (15.9%) needed the support of the pediatric intensive care unit. When coinfections were excluded, children with EV-D68 infection presented with increased work of breathing, recurrent wheezing or asthmatic crisis, more frequently than those with ARI associated with EV non-D68. Moreover, clinical outcomes (hospitalization, respiratory support) were more severe. All 44 EV-D68 strains detected belonged to lineage B3.

CONCLUSIONS

EV-D68 circulated widely in Gipuzkoa during 2016 and was associated with severe ARI. In children with severe ARI of unknown etiology, the presence of EV-D68 should be considered.

Epidemiology of Infections and Development of Asthma

Asthma and allergic diseases have become more prevalent, although the reasons for this increase in disease burden are not known. Understanding why these diseases have become more common requires knowledge of the disease pathogenesis. Multiple studies have identified respiratory viral infections and atypical bacteria as potential etiologic agents underlying the development of asthma (and possibly allergies). This review discusses the epidemiology and potential mechanistic studies that provide links between these infectious agents and the development (and exacerbation) of asthma. These studies provide insight into the increase in disease prevalence and have identified potential targets for future therapeutic intervention.

The Resource Burden of Infections With Rhinovirus/Enterovirus, Influenza, and Respiratory Syncytial Virus in Children

We reviewed the resource utilization of patients with human rhinovirus/enterovirus (HRV/ENT), influenza A/B (FLU), or respiratory syncytial virus (RSV). A total of 2013 patients with nasopharyngeal swabs positive for HRV/ENT, RSV, or FLU were included. Records were reviewed for respiratory support, vascular access procedures, emergency department care only versus admission versus pediatric intensive care unit (PICU) care, antibiotics, length of stay, and billing data. Of the 2013 subjects, 1251 tested positive for HRV/ENT, 558 for RSV, and 204 for FLU. Fewer HRV/ENT patients were discharged from the emergency department ( P < .001); and they were more likely to be admitted to the pediatric intensive care unit ( P < .001). HRV/ENT and RSV patients were more likely to require invasive procedures ( P = .01). Median hospital costs for HRV/ENT patients were more than twice that of FLU patients ( P < .001). HRV/ENT infection in pediatric patients poses a significant resource and cost burden, even when compared with other organisms.

Enterovirus D-68 in children presenting for acute care in the hospital setting

BACKGROUND

Severe respiratory disease associated with enterovirus D68 (EV-D68) has been reported in hospitalized pediatric patients. Virologic and clinical characteristics of EV-D68 infections exclusively in patients presenting to a hospital Emergency Department (ED) or urgent care have not been well defined.

METHODS

Mid-nasal swabs from pediatric patients with respiratory symptoms presenting to the ED or urgent care were evaluated using a commercial multiplex PCR platform. Specimens positive for rhinovirus/enterovirus (HRV/EV) were subsequently tested using real-time reverse-transcriptase PCR for EV-D68. The PCR cycle threshold (CT) was used as a viral load proxy. Clinical outcomes were compared between patients with EV-D68 and patients without EV-D68 who tested positive for HRV/EV.

RESULTS

From August to December 2014, 511 swabs from patients with HRV/EV were available. EV-D68 was detected in 170 (33%) HRV/EV-positive samples. In multivariable models adjusted for age and underlying asthma, patients with EV-D68 were more likely to require hospitalization for respiratory reasons (odds ratio (OR): 3.11, CI: 1.85-5.25), require respiratory support (OR: 1.69, CI: 1.09-2.62), have confirmed/probable lower respiratory tract infection (LRTI; OR: 3.78, CI: 2.03-7.04), and require continuous albuterol or steroids (OR: 3.91, CI: 2.22-6.88 and OR: 4.73, CI: 2.65-8.46, respectively). Higher EV-D68 viral load was associated with need for respiratory support and LRTI in multivariate models.

CONCLUSIONS

Among pediatric patients presenting to the ED or urgent care, EV-D68 causes more severe disease than non-EV-D68 HRV/EV independent of underlying asthma. High viral load was associated with worse clinical outcomes. Rapid and quantitative viral testing may help identify and risk stratify patients.

Discharge Criteria for Bronchiolitis: An Unmet Need

BACKGROUND

Admission criteria and standardized management strategies for bronchiolitis are addressed in several guidelines and have shown to be beneficial; however, guidance regarding discharge criteria is limited and widely variable. We assessed the impact on clinical outcomes of a discharge protocol for children <2 years of age hospitalized with bronchiolitis in a tertiary care pediatric hospital.

METHODS

In October 2013, a protocol to standardize the discharge of children with bronchiolitis was implemented in the infectious diseases (ID) ward but not in other pediatric units caring for these children (non-ID). The protocol included objective clinical criteria and a standardized oxygen weaning pathway. Patients were identified via International Classification of Diseases-9 codes and data manually reviewed. We compared length of stay (LOS) and readmission rates within 2 weeks of discharge according to protocol implementation (ID versus non-ID), adjusted for demographic factors, comorbidities, viral etiology and stratified by pediatric intensive care unit admission.

RESULTS

From October 2013 to May 2015, 1118 children were hospitalized in ID and 695 in non-ID units. Median age was 4.5 months, 55% were males and 28% had comorbidities. LOS was 36% longer in non-ID units (risk ratio: 1.36 [1.27-1.45]; P < 0.001) adjusted for age, gender, comorbidities and viral etiology. Difference in LOS remained significant after excluding children with comorbidities and stratifying by pediatric intensive care unit admission. Readmission rates were comparable between units (ID, 2.9% versus non-ID, 2.6%).

CONCLUSIONS

A standardized discharge protocol for bronchiolitis reduced LOS without increasing readmission rates. Unifying bronchiolitis discharge criteria and oxygen weaning pathways could positively impact hospital-based patient care for this condition.

Comparison of the Severity of Respiratory Disease in Children Testing Positive for Enterovirus D68 and Human Rhinovirus

OBJECTIVE

To compare the characteristics and severity of respiratory disease in children testing positive for enterovirus D68 (EV-D68) and for human rhinovirus (RhV).

STUDY DESIGN

A retrospective single center study of children presenting with acute respiratory symptoms and positive polymerase chain reaction for RhV/EV from September 1, 2014 through October 31, 2014 was performed. Specimens were subsequently tested specifically for EV-D68 and specimens identified as RhV were subtyped when possible into RhV-A, RhV-B, and RhV-C species. Clinical manifestations in patients with EV-D68 were compared with those with non-EV-D68, RhV, and RhV-C.

RESULTS

Of the 173 patients included in the analysis, 72 tested positive for EV-D68, 61 for RhV, and 30 for RhV-C. There were significantly fewer infants in the EV-D68 group. Patients with EV-D68 were more likely than those without EV-D68, and specifically with RhV-C, to have fever and wheezing. Patients with EV-D68 received more magnesium sulfate for respiratory distress not responding adequately to repeated doses of inhaled albuterol. Hospitalized patients with EV-D68 received more bronchodilator therapy than patients with RhV. Patients with EV-D68 were more likely to be admitted to the intensive care unit and were older than patients without EV-D68. There was no difference in length of overall hospitalization or time in the pediatric intensive care unit.

CONCLUSIONS

Children with EV-D68 appeared to have more severe respiratory disease on admission than children with RhV as evidenced by higher rates of fever, wheezing, bronchodilator use and pediatric intensive care unit admission. Despite the initial difference in severity, no significant difference in length of stay was found suggesting that patients with EV-D68 recovered as quickly as other groups.

Enterovirus D68 Infection Among Children With Medically Attended Acute Respiratory Illness, Cincinnati, Ohio, July-October 2014

Background

Enterovirus D68 (EV-D68) caused a widespread outbreak of respiratory illness in the United States in 2014, predominantly affecting children. We describe EV-D68 rates, spectrum of illness, and risk factors from prospective, population-based acute respiratory illness (ARI) surveillance at a large US pediatric hospital.

Methods

Children <13 years of age with ARI and residence in Hamilton County, Ohio were enrolled from the inpatient and emergency department (ED) settings at a children's hospital in Cincinnati, Ohio, from 1 July to 31 October 2014. For each participant, we interviewed parents, reviewed medical records, and tested nasal and throat swabs for EV-D68 using real-time reverse- transcription polymerase chain reaction assay.

Results

EV-D68 infection was detected in 51 of 207 (25%) inpatients and 58 of 505 (11%) ED patients. Rates of EV-D68 hospitalization and ED visit were 1.3 (95% confidence interval [CI], 1.0-1.6) and 8.4 per 1000 children <13 years of age, respectively. Preexisting asthma was associated with EV-D68 infection (adjusted odds ratio, 3.2; 95% CI, 2.0-5.1). Compared with other ARI, children with EV-D68 were more likely to be admitted from the ED (P ≤ .001), receive supplemental oxygen (P = .001), and require intensive care unit admission (P = .04); however, mechanical ventilation was uncommon (2/51 inpatients; P = .64), and no deaths occurred.

Conclusions

During the 2014 EV-D68 epidemic, high rates of pediatric hospitalizations and ED visits were observed. Children with asthma were at increased risk for medically attended EV-D68 illness. Preparedness planning for a high-activity EV-D68 season in the United States should take into account increased healthcare utilization, particularly among children with asthma, during the late summer and early fall.

Concurrent Community Transmission of Enterovirus D68 With Human Rhinoviruses and Respiratory Syncytial Virus Among Children in Sendai, Japan

BACKGROUND

In the autumn of 2015, we experienced a surge in the number of pediatric cases of wheeze in our hospital, which was suspected to be caused by enterovirus (EV)-D68 transmission in the community. Thus, we implemented an ad hoc retrospective surveillance for EV-D68.

METHODS

Patients <15 years of age with acute respiratory infection were eligible for inclusion in this study. All enrolled patients underwent virus detection test. Additionally, neutralization tests (NTs) were performed using the stored serum samples of the enrolled patients to compare the antigenicity of the virus isolated in this study with that isolated in 2010 and evaluate the anti-EV-D68 antibody prevalence.

RESULTS

Respiratory syncytial virus (RSV) was the most commonly detected virus (35%), followed by EV-D68 (19%) and non-EV-D68 enteroviruses/human rhinoviruses (14%). Patients with EV-D68 infection had higher median age than those with RSV infection (P < 0.05). Moreover, patients with EV-D68 infection showed a higher expiratory wheeze prevalence than those with non-EV-D68 enterovirus/rhinovirus and RSV infections. The antigenicity of the isolate from the current study was similar to the virus that circulated in 2010. At the early study phase, children in our community did not have high NT titers, but the median log NT titer increased from 1.5 to 5 over time (P < 0.05).

CONCLUSION

This study showed the concurrent circulation of EV-D68 with non-EV-D68 enteroviruses/rhinoviruses and RSV in infants and children in our community and captured the early stage of EV-D68 transmission.

Enterovirus-D68 (EV-D68) in pediatric patients with respiratory infection: The circulation of a new B3 clade in Italy

BACKGROUND

In recent years, several outbreaks due to Enterovirus D-68 (EV-D68) have been reported, and it was confirmed that the virus can cause upper and lower respiratory tract diseases and be associated with the development of neurological problems.

OBJECTIVES

The main aim of this research was to study the genetic characteristics of EV-D68 strains that were circulating in Italy identified during an outbreak of an EV-D68 infection that occurred in Italy during the period March-October 2016.

STUDY DESIGN

A retrospective study of the circulation of different types and subtypes of EV-D68 was performed. Nasopharyngeal swabs were collected from March 2016 through October 2016 in children admitted to the Emergency Room with respiratory diseases.

RESULTS

Among 390 children, 22 (59.1% males; mean age 47 months) were found to be infected by EV-D68 and most of them were immunocompetent (72.7%). Pneumonia was diagnosed in 12 (54.5%) children. Phylogenetic analysis of the VP1 region showed that all the strains identified in this study belonged to clade B3. Within B3 subclade, the Italian EV-D68 strains were most closely related to strains detected in Southern China in 2015 as well as to strains detected in US and the Netherlands in 2016.

CONCLUSIONS

These results showed that EV-D68 infections are a common cause of lower respiratory illness in pediatric age. The circulation of one EV-D68 lineage has been proven in Italy and in the European region during 2016. However, further studies are required to investigate whether some strains or lineages may possess a higher affinity for the lower airway or central nervous system.

Clinical characteristics of children infected with enterovirus D68 in an outpatient clinic and the association with bronchial asthma

BACKGROUND

All reports of increases in severe respiratory disease associated with human enterovirus D68 (EV-D68) are from hospital settings. However, there are few reports describing clinical characteristics in less severely affected populations.

METHODS

We conducted a retrospective observational study from January 2010 to December 2015 in Yamagata, Japan. Using regional passive surveillance, 5794 respiratory specimens were collected from children who initially presented to an outpatient clinic with acute respiratory symptoms. The collected samples were tested for EV-D68 by reverse transcription PCR.

RESULTS

EV-D68 was detected in 79 specimens mainly during the two epidemic periods in August-October 2010 and August-October 2015, when detection rates were 10.2% (31 of 304 specimens) and 16.3% (46 of 282 specimens), respectively. Among the 69 EV-D68-positive children, excluding those with viral coinfection, 39 (57%) had upper respiratory tract infections, 23 (33%) bronchiolitis or asthma attack, 5 (7%) bronchitis, 1 (1%) meningitis and 1 (1%) acute flaccid paralysis. In 23 children with wheezing, retraction was observed in 10 (43%), and six (26%) were diagnosed with asthma exacerbation. Six children required hospital admission, five (83%) because of asthma exacerbation. A history of asthma or wheezing was the most significant risk factor for the development of wheezing (odds ratio, 8.23; 95% CI, 2.65-25.50; p < .001).

CONCLUSIONS

The low rate of hospitalization (9%, 6 of 69) indicates that most cases with EV-D68 infection were managed as outpatients. A history of asthma or wheezing was a potential risk factor for wheezing, resulting in hospitalization due to a severe asthma attack.