Characteristics of GII.4 Norovirus Versus Other Genotypes in Sporadic Pediatric Infections in Davidson County, Tennessee, USA.

BACKGROUND: Norovirus is a leading cause of epidemic acute gastroenteritis (AGE), with most outbreaks occurring during winter. The majority of outbreaks are caused by GII.4 noroviruses; however, data to support whether this is true for sporadic medically attended AGE are limited. Therefore, we sought to compare the clinical characteristics and seasonality of GII.4 vs non-GII.4 viruses. METHODS: Children aged 15 days -17 years with AGE symptoms were recruited from the outpatient, emergency department, and inpatient settings at Vanderbilt Children's Hospital, Davidson County, Nashville, Tennessee, from December 2012 -November 2015. Stool specimens were tested using qRT-PCR for GI and GII noroviruses and subsequently genotyped by sequencing a partial region of the capsid gene. RESULTS: A total of 3705 patients were enrolled, and stool specimens were collected and tested from 2885 (78%) enrollees. Overall, 636 (22%) samples were norovirus-positive, of which 567 (89%) were GII. Of the 460 (81%) genotyped GII-positive samples, 233 (51%) were typed as GII.4 and 227 (49%) as non-GII.4. Compared with children with non-GII.4 infections, children with GII.4 infections were younger, more likely to have diarrhea, and more likely to receive oral rehydration fluids. Norovirus was detected year-round and peaked during winter. CONCLUSIONS: Approximately 40% of sporadic pediatric norovirus AGE cases were caused by GII.4 norovirus. Children infected with GII.4 had more severe symptoms that required more medical care. Seasonal variations were noticed among different genotypes. These data highlight the importance of continuous norovirus surveillance and provide important information on which strains pediatric norovirus vaccines should protect against.

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.

Utility of RSV rapid diagnostic assays in hospitalized children in Amman, Jordan.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading cause of acute respiratory infections in children worldwide and a frequent cause of hospitalization. Rapid diagnostic assays (RDAs) are available for RSV and they help guide management; however, they are underutilized in developing countries. We compared molecular diagnostics to RSV RDA in hospitalized children in Amman, Jordan. MATERIALS AND METHODS: Children under 2 years of age, admitted with fever and/or respiratory symptoms were enrolled prospectively from March 2010 to 2012. Demographic and clinical data were collected through parent/guardian interviews and medical chart abstraction. RSV RDAs were performed, and nasal/throat swabs were tested for RSV using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). RESULTS: RSV RDA and PCR were performed on specimens from 1271 subjects. RSV RDA had a sensitivity of 26% and a specificity of 99%, with positive and negative predictive values of 98.6% and 43%, respectively. RDA-positive patients had fewer days of symptoms at presentation and were more likely to have a history of prematurity, lower birth weight, require supplemental oxygen, and a longer hospitalization as compared with subjects with negative RDA. Multivariate analysis showed only lower birth weight, lack of cyanosis on examination, and lower cycle threshold to be independently associated with positive RDA (p ≤ .001). CONCLUSION: RSV RDAs had high specificity, but low sensitivity as compared with qRT-PCR. Positive RDA was associated with patients with a more severe disease, as indicated by oxygen use, longer length of stay, and higher viral load. Implementation of RDAs in developing countries could be an inexpensive and expedient method for predicting RSV disease severity and guiding management.

Evaluating the diagnostic accuracy of the WHO Severe Acute Respiratory Infection (SARI) criteria in Middle Eastern children under two years over three respiratory seasons.

OBJECTIVE: The World Health Organization created the Severe Acute Respiratory Infection (SARI) criteria in 2011 to monitor influenza (flu)-related hospitalization. Many studies have since used the SARI case definition as inclusion criteria for surveillance studies. We sought to determine the sensitivity, specificity, positive predictive value, and negative predictive value of the SARI criteria for detecting ten different respiratory viruses in a Middle Eastern pediatric cohort. MATERIALS AND METHODS: The data for this study comes from a prospective acute respiratory surveillance study of hospitalized children <2 years in Amman, Jordan from March 16, 2010 to March 31, 2013. Participants were recruited if they had a fever and/or respiratory symptoms. Nasal and throat swabs were obtained and tested by real-time RT-PCR for eleven viruses. Subjects meeting SARI criteria were determined post-hoc. Sensitivity, specificity, positive predictive value, and negative predictive value of the SARI case definition for detecting ten different viruses were calculated and results were stratified by age. RESULTS: Of the 3,175 patients enrolled, 3,164 were eligible for this study, with a median age of 3.5 months, 60.4% male, and 82% virus-positive (44% RSV and 3.8% flu). The sensitivity and specificity of the SARI criteria for detecting virus-positive patients were 44% and 77.9%, respectively. Sensitivity of SARI criteria for any virus was lowest in children <3 months at 22.4%. Removing fever as a criterion improved the sensitivity by 65.3% for detecting RSV in children <3 months; whereas when cough was removed, the sensitivity improved by 45.5% for detecting flu in same age group. CONCLUSIONS: The SARI criteria have poor sensitivity for detecting RSV, flu, and other respiratory viruses-particularly in children <3 months. Researchers and policy makers should use caution if using the criteria to estimate burden of disease in children.

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.

Temporal and Genotypic Associations of Sporadic Norovirus Gastroenteritis and Reported Norovirus Outbreaks in Middle Tennessee, 2012-2016.

BACKGROUND: In the United States, surveillance of norovirus gastroenteritis is largely restricted to outbreaks, limiting our knowledge of the contribution of sporadic illness to the overall impact on reported outbreaks. Understanding norovirus transmission dynamics is vital for improving preventive measures, including norovirus vaccine development. METHODS: We analyzed seasonal patterns and genotypic distribution between sporadic pediatric norovirus cases and reported norovirus outbreaks in middle Tennessee. Sporadic cases were ascertained via the New Vaccine Surveillance Network in a single county, while reported norovirus outbreaks from 7 middle Tennessee counties were included in the study. We investigated the predictive value of sporadic cases on outbreaks using a 2-state discrete Markov model. RESULTS: Between December 2012 and June 2016, there were 755 pediatric sporadic norovirus cases and 45 reported outbreaks. Almost half (42.2%) of outbreaks occurred in long-term care facilities. Most sporadic cases (74.9%) and reported outbreaks (86.8%) occurred between November and April. Peak sporadic norovirus activity was often contemporaneous with outbreak occurrence. Among both sporadic cases and outbreaks, GII genogroup noroviruses were most prevalent (90.1% and 83.3%), with GII.4 being the dominant genotype (39.0% and 52.8%). The predictive model suggested that the 3-day moving average of sporadic cases was positively associated with the probability of an outbreak occurring. CONCLUSIONS: Despite the demographic differences between the surveillance populations, the seasonal and genotypic associations between sporadic cases and outbreaks are suggestive of contemporaneous community transmission. Public health agencies may use this knowledge to expand surveillance and identify target populations for interventions, including future vaccines.

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.

Severe outcomes associated with respiratory viruses in newborns and infants: a prospective viral surveillance study in Jordan.

OBJECTIVE: To assess virus-specific hospitalisation rates, risk factors for illness severity and seasonal trends in children hospitalised with acute respiratory infections (ARI). DESIGN: Prospective cohort study. SETTING: A government hospital serving low-income and middle-income population in Amman, Jordan. PARTICIPANTS: Children under 2 years of age hospitalised with fever and/or respiratory symptoms (n=3168) from 16 March 2010 to 31 March 2013. Children with chemotherapy-associated neutropenia and newborns who had never been discharged after birth were excluded from the study. OUTCOME MEASURES: Hospitalisation rates and markers of illness severity: admission to intensive care unit (ICU), mechanical ventilation (MV), oxygen therapy, length of stay (LOS) and death. RESULTS: Of the 3168 subjects, 2581 (82%) had at least one respiratory virus detected, with respiratory syncytial virus (RSV) being the most predominant pathogen isolated. During admission, 1013 (32%) received oxygen therapy, 284 (9%) were admitted to ICU, 111 (4%) were placed on MV and 31 (1%) children died. Oxygen therapy was higher in RSV-only subjects compared with human rhinovirus-only (42%vs29%, p<0.001), adenovirus-only (42%vs21%, p<0.001) and human parainfluenza virus-only (42%vs23%, p<0.001) subjects. The presence of an underlying medical condition was associated with oxygen therapy (adjusted OR (aOR) 1.95, 95% CI 1.49 to 2.56), ICU admission (aOR 2.51, 95% CI 1.71 to 3.68), MV (aOR 1.91, 95% CI 1.11 to 3.28) and longer LOS (aOR1.71, 95% CI 1.37 to 2.13). Similarly, younger age was associated with oxygen therapy (0.23, 95% CI 0.17 to 0.31), ICU admission (aOR 0.47, 95% CI 0.30 to 0.74), MV (0.28, 95% CI 0.15 to 0.53) and longer LOS (aOR 0.47, 95% CI 0.38 to 0.59). Pneumonia was strongly associated with longer LOS (aOR 2.07, 95% CI 1.65 to 2.60), oxygen therapy (aOR 2.94, 95% CI 2.22 to 3.89), ICU admission (aOR 3.12, 95% CI 2.16 to 4.50) and MV (aOR 3.33, 95% CI 1.85 to 6.00). Virus-specific hospitalisation rates ranged from 0.5 to 10.5 per 1000 children. CONCLUSION: Respiratory viruses are associated with severe illness in Jordanian children hospitalised with ARI. Prevention strategies such as extended breast feeding, increased access to palivizumab and RSV vaccine development could help decrease hospitalisation rates and illness severity, particularly in young children with underlying medical conditions.

Predictors of Intravenous Immunoglobulin Nonresponse and Racial Disparities in Kawasaki Disease.

BACKGROUND: Kawasaki disease (KD) is the most common cause of acquired heart disease in American children. Intravenous immunoglobulin (IVIG) nonresponse is a known risk factor for cardiac sequelae. Previously reported risk factors for nonresponse include age, male sex and laboratory abnormalities. We set out to identify additional risk factors for IVIG nonresponse in a racially diverse KD population. METHODS: We conducted a retrospective chart review at a referral center in the Southeastern United States of children meeting ICD-9 (International Statistical Classification of Disease and Related Health Problems) criteria for KD and being treated with IVIG. RESULTS: Four-hundred and fifty-nine children met inclusion criteria, 67 were excluded for subsequent rheumatologic diagnosis, unknown race, or failure to meet the American Heart Association guideline criteria. Our final cohort consisted of 392 subjects, with median age of 2.7 years, 65.1% male, 66.1% White, 24.2% Black, 4.9% Asian and 82.9% responded to a single dose of IVIG. Coronary ectasia or aneurysm developed in 27%; 7.4% developed aneurysms and 2.3% giant coronary aneurysms. Nonresponders were more likely to be Black, have higher white blood cell, erythrocyte sedimentation rate and C-reactive protein, lower hemoglobin, develop ectasia or aneurysm and require critical care and hospital readmission. Responders achieved echocardiographic normalization more often compared with nonresponders (81.3% vs. 60.9%, P = 0.002) and coronary artery pseudonormalization (87.2% vs. 69.7%, P = 0.03) at 1 year. Black nonresponders had the slowest normalization at 1 year (52.9%, P = 0.02). CONCLUSIONS: Nonresponders have higher rates and greater severity of coronary involvement than responders. Our study uniquely demonstrates Black race as a risk factor for nonresponse and for delayed normalization of cardiac involvement at 1-year follow-up.