Background Norovirus is a leading cause of epidemic acute gastroenteritis (AGE) in the U.S, with most outbreaks occurring during winter. The majority of outbreaks are caused by GII.4 noroviruses, but data supporting 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 in children presenting with vomiting and/or diarrhea. Methods Children from 15 days to 17 years with AGE symptoms were recruited from the outpatient, emergency department, and inpatient settings at Vanderbilt Children's Hospital, Davidson County, Nashville, TN from 12/2012-11/2015. Stool specimens were tested by RT-qPCR for GI and GII noroviruses and subsequently genotyped by sequencing a partial region of the capsid gene. Results A total of 3705 subjects were enrolled and stool specimens were collected and tested from 2885 (78%) of 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 to children with non-GII.4 infections, children with GII.4 infections were younger, more likely to have diarrhea and receive oral rehydration fluids. Norovirus was detected year-round but peaked during winter. Conclusion Approximately half of sporadic pediatric norovirus AGE cases were caused by GII.4 norovirus. Children infected with GII.4 had more severe symptoms requiring 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.

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.

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Background The rates of early-onset Group B Streptococcus (GBS) disease (EOGBS) have declined since the implementation of universal screening and intrapartum antibiotic prophylaxis guidelines but late-onset (LOGBS) rates remain unchanged. Racial differences in GBS disease rates have been previously documented with Black infants having higher rates of EOGBS and LOGBS, but it is not known if these have persisted. Therefore, we sought to determine the differences of EOGBS and LOGBS disease by race over the past decade in Tennessee. Methods This study used active population-based and laboratory-based surveillance data for invasive GBS disease conducted through Active Bacterial Core surveillance in selected counties across Tennessee. We included infants younger than 90 days and who had invasive GBS disease between 2009-2018. Results A total of 356 GBS cases were included, with 60% having LOGBS. EOGBS and LOGBS had decreasing temporal trends over the study period. Overall, there were no changes of temporal trend noted in the rates of EOGBS and LOGBS among White race. However, Black infants had a significantly decreasing EOGBS and LOGBS temporal trends, [(RR=0.87, 95% CI= [0.79, 0.96], P-value=0.007), (RR= 0.90, 95% CI= [0.84, 0.97], P-value=0.003)], respectively. Conclusions Years after the successful implementation of the universal screening guidelines, our data revealed an overall decrease in LOGBS rates, primarily driven by changes among infants of Black race. More studies are needed to characterize the racial disparities in GBS rates, and factors driving them. Prevention measures such as vaccination are needed to have a further impact on disease rates.