Shedding of measles vaccine RNA in children after receiving measles, mumps and rubella vaccination.

BACKGROUND: Measles, mumps, and rubella(MMR) vaccination is critical to measles outbreak responses. However, vaccine reactions and detection of measles vaccine RNA in recently immunized persons may complicate case classification especially in those presenting with another respiratory viral illness. We aim to characterize cases of measles vaccine shedding in recently vaccinated children presenting with respiratory viral symptoms. METHODS: Children who were tested with a multiplex respiratory panel <30 days after receiving MMR were identified. Remnant nasopharyngeal(NP) samples were tested for measles vaccine by PCR. Medical records were reviewed for demographics, presenting symptoms, and test results. RESULTS: From January 2022 to March 2023, 127 NP from children who received MMR were tested. Ninety-six NP were collected after the first dose, of which 33(34.4 %) were positive for vaccine RNA. The median interval between MMR and detection was 11.0 days. Thirty-one NP were collected after the second MMR and 1(3.2 %) was positive; time between the vaccination and detection was 18.9 days. Median cycle threshold(Ct) value of the measles PCR for vaccine shedding was significantly higher than median Ct in children with wild-type infection. CONCLUSION: Shedding of measles vaccine RNA is not uncommon and vaccine RNA can be detected up to 29 days post MMR; the amount of vaccine RNA shedding is low indicated by high Ct values. Clinicians and public health officials should consider performing measles vaccine testing on those testing positive for measles within one month of MMR vaccination, especially if the Ct value is high and definitive epidemiological links are absent.

Etiologies of bloody diarrhea in children presenting with acute gastroenteritis to US emergency departments.

Among 111 children presenting with bloody diarrhea in a multicenter study of molecular testing in US emergency departments, we found viral pathogens in 18%, bacteria in 48%, protozoa in 2%, and no pathogens detected in 38%.

Maternal and congenital human cytomegalovirus infection: laboratory testing for detection and diagnosis.

Human cytomegalovirus (CMV) is the leading cause of congenital infection worldwide and the most common cause of non-genetic sensorineural hearing loss. As there is no vaccine or other specific intervention to prevent congenital CMV infection, there is a need to identify maternal and congenital infections with sensitive and specific testing as early as possible. There is no widely accepted practice for screening during pregnancy or in all newborns for identification of possible cases of congenital CMV. Currently, screening during pregnancy is limited to those identified as at risk followed by fetal and/or neonatal testing when congenital infection is suspected. This review focuses primarily on the current status of laboratory testing for diagnosis of maternal and congenital CMV infections. Primary maternal infection is best diagnosed using serologic testing, including CMV IgM, IgG, and avidity testing, while fetal infection should be assessed by nucleic acid amplification testing (NAAT) of amniotic fluid. Urine and saliva NAATs are the mainstay for diagnosis of congenital CMV in the first 3 weeks of life. Testing of dried blood spots can be useful for diagnosis of congenital CMV outside of the newborn period. The gaps in knowledge such as the prognostic value of viral loads in various sample types are addressed.

Clinical Impact of Multiplex Molecular Diagnostic Testing in Children With Acute Gastroenteritis Presenting to an Emergency Department: A Multicenter Prospective Study.

BACKGROUND: Multiplex molecular diagnostic panels have greatly enhanced detection of gastrointestinal pathogens. However, data on the impact of these tests on clinical and patient-centered outcomes are limited. METHODS: We conducted a prospective, multicenter, stepped-wedge trial to determine the impact of multiplex molecular testing at 5 academic children's hospitals on children presenting to the emergency department with acute gastroenteritis. Caregivers were interviewed on enrollment and 7-10 days after enrollment to determine symptoms, risk factors, subsequent medical visits, and impact on family members. During the pre-intervention period, diagnostic testing was performed at the clinician's discretion . During the intervention period, multiplex molecular testing was performed on all children, with results available to clinicians. The primary outcome was return visits to a healthcare provider within 10 days of enrollment. RESULTS: Potential pathogens were identified by clinician-ordered tests in 19 of 571 (3.3%) in the pre-intervention period compared with 434 of 586 (74%) in the intervention period; clinically relevant pathogens were detected in 2.1% and 15%, respectively. In the multivariate model, the intervention was associated with a 21% reduction in the odds of any return visit (odds ratio, 0.79; 95% confidence interval, .70-.90) after adjusting for potential confounders. Appropriate treatment was prescribed in 11.3% compared with 19.6% during the intervention period (P = .22). CONCLUSIONS: Routine molecular multiplex testing for all children who presented to the ED with acute gastroenteritis detected more clinically relevant pathogens and led to a 21% decrease in return visits. Additional research is needed to define patients most likely to benefit from testing. Clinical Trials Registration. NCT02248285.

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.

Clinical Impact of Multiplex Molecular Diagnostic Testing in Children with Acute Gastroenteritis Presenting to An Emergency Department: A Multicenter Prospective Study.

Background: Multiplex molecular diagnostic panels have greatly enhanced detection of gastrointestinal pathogens. However, data on the impact of these tests on clinical and patient-centered outcomes are limited. Methods: We conducted a prospective, multicenter, stepped-wedge trial to determine the impact of multiplex molecular testing at five academic children's hospitals in children presenting to the ED with acute gastroenteritis. Caregivers were interviewed on enrollment and again 7-10 days after enrollment to determine symptoms, risk factors, subsequent medical visits, and impact on family members. During the pre-intervention period, diagnostic testing was performed at the discretion of clinicians. During the intervention period, multiplex molecular testing was performed on all children with results available to clinicians. Primary outcome was return visits to a health care provider within 10 days of enrollment. Results: Potential pathogens were identified by clinician ordered tests in 19/571 (3.3%) in the pre-intervention period compared to 434/586 (74%) in the intervention period; clinically relevant pathogens were detected in 2.1% and 15% respectively. In the multivariate model adjusting for potential confounders, the intervention was associated with a 21% reduction in the odds of any return visit (OR 0.79; 95% CI 0.70-0.90). Appropriate treatment was prescribed in 11.3% compared to 19.6% during the intervention period(P=0.22). Conclusions: Routine molecular multiplex testing for all children presenting to the ED with AGE detected more clinically relevant pathogens and led to a 21% decrease in return visits. Additional research is needed to define patients most likely to benefit from testing.

Performance comparison of three commercial tests for the detection of SARS-CoV-2 antibodies in a common set of pediatric samples.

BACKGROUND: Serologic testing for SARS CoV-2 is useful for detection of past infection and assisting in diagnosis of post-COVID-19 syndromes such as MIS-C. Immune responses to SARS-CoV-2 infection in children differ from adults but most antibody performance studies are limited to adults. OBJECTIVE: The objective of this study was to compare three commercial SARS-CoV-2 antibody kits in a common set of children being evaluated for SARS-CoV-2 infection. METHODS: Three SARS-CoV-2 antibody tests: Abbott anti-nucleocapsid (N) IgG (AA), Epitope Diagnostics anti-N IgG (EDI) and EUROIMMUN anti-S1 Spike IgG (EU) were compared against two references: 1) RT-PCR and 2) consensus IgG (consIgG). RESULTS: All three tests had a sensitivity <53% compared to RT-PCR, with EU outperforming EDI (p = 0.03). When all samples were compared to consIgG, positive percent agreement was comparable (AA-90%, EU- 98% and EDI- 88%) but EDI had significantly better negative percent agreement than EU (p = 0.009). No difference in test performance was observed using either reference when samples were collected ≥15 days post-symptom onset (PSO). CONCLUSIONS: Our findings suggest good performance of commercial SARS-CoV-2 IgG assays in pediatric patients with samples collected ≥15 days PSO. Additional studies investigating antibody response and assay performance in children are warranted.

Detection of human herpesvirus 6 in pediatric CSF samples: causing disease or incidental distraction?

Interpretation of human herpesvirus type 6 (HHV6) detection in the cerebrospinal fluid (CSF) of children can be complex; the virus can cause acute infection, reactivation, or can be inherited chromosomally integrated (iciHHV6). Our objectives were to determine the prevalence of HHV6 including iciHHV6 in CSF and compare the clinical and laboratory characteristics with and without iciHHV6 in our patient population. Overall, the prevalence of HHV6 and iciHHV6 was 2.4% and 0.85%, respectively. Children with iciHHV6 were significantly younger and less likely to present with fever. Septic infants (≤60 days) accounted for 65.2% (15/23) of the iciHHV6 patients. Patients with iciHHV6 had higher viral loads in CSF and whole blood. Twenty-one (91.3%) patients with iciHHV6 and 12 (33.3%) without ici-HHV6 were determined to have an incidental detection of HHV6 not associated with presenting symptoms. Molecular detection of HHV6 in CSF is not always associated with HHV6 infection and may represent iciHHV6 particularly in infants evaluated for sepsis.

Multicenter Evaluation of the DiaSorin Molecular Simplexa Congenital CMV Direct PCR Test on Neonatal Saliva and Urine Specimens.

Cytomegalovirus (CMV) is the most common virus associated with congenital infection worldwide and is a major cause of sensorineural hearing loss (SNHL) and developmental delay. Up to 90% of infants with congenital CMV (cCMV) infection are asymptomatic at birth, making the diagnosis challenging. Postnatal diagnosis involves testing newborn saliva and/or urine collected before 21 days of life to confirm cCMV infection. This multicenter study evaluated the performance of the Simplexa Congenital CMV Direct real-time PCR assay for the qualitative detection of CMV in newborn saliva (n = 2,023) and urine (n = 1,797) specimens. Compared to two PCR/bidirectional sequencing assays, the Simplexa Congenital CMV Direct assay demonstrated positive percent agreement (PPA) and negative percent agreement (NPA) of 98.6% and 99.9%, respectively, for saliva samples and a PPA of 97.8% and an NPA of 99.9% for urine specimens. Overall concordance was κ = 0.98 or near perfect compared to the composite reference methods with both sample types. By 95% probit analysis, the limit of detection (LoD) using the AD-169 reference strain was 350 ± 12 copies/mL in urine. The LoDs of saliva swabs in either 1 mL or 3 mL of transport medium were 274 ± 12 copies/mL and 300 ± 14 copies/mL, respectively. The Simplexa Congenital CMV Direct assay can be applied to both saliva and urine specimens collected from newborns less than 21 days of age to rapidly and reliably identify CMV infection.

SARS-CoV-2 Reinfection With Different SARS-CoV-2 Variants in Children, Ohio, United States.

BACKGROUND: Beginning in late 2021, we observed a significant increase in SARS-CoV-2 reinfections in pediatric patients evaluated at our institution. We aimed to characterize the children with SARS-CoV-2 reinfection, determine the number of SARS-CoV-2 reinfections, and characterize the intervals between two infections in our patient population. METHODS: From March 2020 to September 2022, we identified children ≤21 years old who had ≥2 SARS-CoV-2 infections using laboratory reports. We then defined the type of SARS-CoV-2 variant in the first and subsequent infections by mutation-specific typing or local epidemiology data. Clinical outcomes and the intervals between SARS-CoV-2 infections were assessed. RESULTS: We identified 541 children with ≥2 SARS-CoV-2 infections. The median interval between two infections was 229 days. The hospitalization rate was lower in the second infection. Reinfection counts were higher during the periods that Omicron variants predominated. Reinfection occurred more rapidly when Omicron variants were circulating with some occurring in less than 90 days. CONCLUSIONS: As SARS-CoV-2 continues to evolve, there is a need for ongoing surveillance to identify the frequency and time interval between reinfections and to re-evaluate the definition of SARS-CoV-2 reinfections.

A Hypothesis-Generating Prospective Longitudinal Study to Assess the Relative Contribution of Common Respiratory Viruses to Severe Lower Respiratory Infections in Young Children.

BACKGROUND: Respiratory viruses such as respiratory syncytial virus (RSV), influenza, parainfluenza and human metapneumovirus are well-established etiologies of acute lower respiratory tract infections (ALRIs; LRI-viruses). In contrast, adenovirus (AdV), rhinovirus/enterovirus (RV/EV) and seasonal human coronaviruses (CoV), collectively termed AdV/RV/CoV, are detected both in healthy children and children with ALRI. METHODS: The methods include a prospective longitudinal case-control study, assessing the prevalence of LRI-viruses versus AdV/RV/CoV in ALRI [community-acquired alveolar pneumonia (CAAP) and bronchiolitis] during hospitalization (visit 1), 7-14 days (visit 2) and 28-35 days (visit 3) in 2-17-month-old children. Controls were 2-27-month-old children hospitalized for elective surgery during the same respiratory seasons. RESULTS: We enrolled 99 infants (37 CAAP, 38 bronchiolitis and 24 controls) and obtained 211 nasopharyngeal swabs. Overall, 163 (77%) had greater than or equal to 1 viruses detected; RV/EV (n = 94; 45%) and RSV (n = 71; 34%) were the most frequently detected viruses. In CAAP, the overall LRI-virus prevalence was 78.4%, 32.4% and 5.4% in visits 1, 2 and 3, respectively; the respective rates in bronchiolitis were 73.7%, 34.5% and 8.0%. In controls, no LRI-viruses were detected. In contrast, the overall AdV/RV/CoV prevalence was high among controls (70.8%) and similar among CAAP (48.6%, 40.5% and 40.5%) and bronchiolitis (47.4, 58.6% and 64.0%) across visits. CONCLUSIONS: Among ALRI cases, LRI-viruses dominated during the acute disease, with prevalence declining within 28-35 days, suggesting their causative role. In contrast, AdV/RV/CoV prevalence was similar during all 3 visits and in controls, suggesting that carriage of these viruses is common during the viral respiratory season. The current study is relatively small and of short duration; however, the findings are supported by other recent studies.

Differences in SARS-CoV-2 Clinical Manifestations and Disease Severity in Children and Adolescents by Infecting Variant.

Since the COVID-19 pandemic began, different SARS-CoV-2 variants have been identified and associated with higher transmissibility than the ancestral nonvariant strain. During January 1, 2021-January 15, 2022, we assessed differences in clinical and viral parameters in a convenience sample of COVID-19 outpatients and inpatients 0-21 years of age in Columbus, Ohio, USA, according to the infecting variant, identified using a mutation-specific reverse transcription PCR assay. Of the 676 patients in the study, 17.75% were infected with nonvariant strains, 18.49% with the Alpha variant, 41.72% with Delta, and 16.42% with Omicron. Rates of SARS-COV-2/viral co-infections were 15.66%-29.41% and were comparable across infecting variants. Inpatients with acute Delta and Omicron infections had lower SARS-CoV-2 cycle threshold values and more frequent fever and respiratory symptoms than those with nonvariant strain infections. In addition, SARS-COV-2/viral co-infections and the presence of underlying conditions were independently associated with worse clinical outcomes, irrespective of the infecting variant.

The Hidden Crisis in the Times of COVID-19: Critical Shortages of Medical Laboratory Professionals in Clinical Microbiology.

The COVID pandemic has put a spotlight on laboratory medicine, showcasing how vital diagnostic testing is for society and the health care system. It has also brought to light and accelerated the critical shortage of trained and experienced laboratory personnel that has been felt for decades. The need for laboratory professionals is expected to grow by 11% between 2020 and 2030, a higher rate of growth than the overall average for all other health care occupations. Here, the background to this workforce shortage is reviewed. Some proposed actions to help address the issue are put forth, including increasing awareness of the medical laboratory science profession along with bolstering training opportunities and awareness of alternate routes to obtaining certification as a medical laboratory scientist. In addition, recent survey data specifically related to the employee shortages in microbiology are presented which demonstrate that 80% of microbiology laboratories have vacant positions and that filling these positions is challenging for a number of reasons, including a lack of qualified applicants.

Clinical Characteristics and Etiology of Community-acquired Pneumonia in US Children, 2015-2018.

BACKGROUND: Pneumonia has a major impact on childhood health and health care costs. This study was designed to obtain contemporary information on the clinical characteristics and etiology of community-acquired pneumonia (CAP) in children from both inpatient and outpatient settings in the USA. METHODS: We conducted a prospective, multicenter, observational study of CAP among previously healthy children 2 months to 18 years of age in 6 children's hospitals in Ohio from 2015 to 2018. For pathogen detection, nasopharyngeal swabs were collected from all subjects. Blood and pleural fluid cultures were available per standard of care. RESULTS: We enrolled a convenience sample of 441 patients: 380 hospitalized and 61 outpatients. Tachypnea and radiologic findings of consolidation and pleural effusion were more frequent among inpatients than outpatients. A pathogen was detected in 64.6% of patients: viruses in 55.6%, atypical bacteria in 8.8% and pyogenic bacteria in 4.3%. Eighteen (4.1%) patients had both viruses and bacteria detected. Rhinovirus/enterovirus (RV; 18.6%) and respiratory syncytial virus (RSV; 16.8%) were the viruses most frequently detected, and Mycoplasma pneumoniae (8.2%) and Streptococcus pneumoniae (2.3%) were the most common bacteria. Except for S. pneumoniae, which was identified more frequently in inpatients, there were no significant differences between inpatients and outpatients in the proportions of children with specific pathogens detected. CONCLUSIONS: Rhinovirus/enterovirus and RSV among viruses and M. pneumoniae and S. pneumoniae among bacteria were the most common pathogens detected in children with CAP. Tachypnea and chest radiographs with consolidation and/or pleural effusion were associated with hospitalization.

A deletion in the N gene of SARS-CoV-2 may reduce test sensitivity for detection of SARS-CoV-2.

One SARS-CoV-2-positive sample demonstrated impaired detection of the N1 target by RT-PCR using US CDC primer/probe sets. A 3 nucleotide deletion was discovered that overlaps the forward primer binding site. This finding underscores the importance of continued SARS-CoV-2 mutation surveillance and assessment of the impact on diagnostic test performance.

Severe Acute Respiratory Syndrome Coronavirus 2 RNAemia and Clinical Outcomes in Children With Coronavirus Disease 2019.

The burden of coronavirus disease 2019 (COVID-19) in children represents a fraction of cases worldwide, yet a subset of those infected are at risk for severe disease. We measured plasma severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in a cohort of 103 children hospitalized with COVID-19 with diverse clinical manifestations. SARS-CoV-2 RNAemia was detected in 27 (26%) of these children, lasted for a median of 6 (interquartile range, 2-9) days, and was associated with higher rates of oxygen administration, admission to the intensive care unit, and longer hospitalization.

Nasopharyngeal Codetection of Haemophilus influenzae and Streptococcus pneumoniae Shapes Respiratory Syncytial Virus Disease Outcomes in Children.

BACKGROUND: The role of nasopharyngeal bacteria in respiratory syncytial virus (RSV) disease has been underestimated. We measured the frequency and burden of respiratory bacteria in the upper respiratory tract of infants with RSV infection over 7 respiratory seasons, and their impact on clinical outcomes. METHODS: Children <2 years old with mild (outpatients, n=115) or severe (inpatients, n=566) RSV infection, and matched healthy controls (n=161) were enrolled. Nasopharyngeal samples were obtained for RSV, Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis, and Haemophilus influenzae detection and quantitation by PCR. Multivariable models were constructed to identify variables predictive of severe disease. RESULTS: S. pneumoniae, H. influenzae, and M. catarrhalis, but not S. aureus, were detected more frequently in RSV-infected children (84%) than healthy controls (46%; P<.001). Detection of S. pneumoniae and/or H. influenzae was associated with fever, more frequent antibiotic treatment, worse radiologic findings, and higher neutrophil counts (P<.01). In adjusted analyses, S. pneumoniae/H. influenzae codetection was independentlyassociated with greater odds of hospitalization, higher disease severity scores, need for supplemental oxygen, and longer hospitalization. CONCLUSIONS: Nasopharyngeal codetection of S. pneumoniae and H. influenzae in infants with RSV infection is associated with increased disease severity.

Evaluation of the Cepheid Xpert SA Nasal Complete for direct detection of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus in nasal swabs from pediatric patients.

Nasal carriers of Staphylococcus aureus (SA) are at increased risk for health-care associated infections with this organism. Timely detection of SA and Methicillin-resistant SA (MRSA) and subsequent decolonization are important components of infection control. While performance of nucleic acid amplification-based tests for detection of SA/MRSA in adults has been well-described, limited data are available in children. Our objective was to evaluate the performance of the Xpert SA in pediatric patients. Overall, for detection of SA, Xpert SA demonstrated a sensitivity and specificity of 95.1% and 93.5%, respectively and 87.8% sensitive and 98.1% specific for detection of MRSA. Performance in different age groups was similar but neonates had the lowest sensitivity and highest invalid rates. The Xpert SA is a rapid, reliable test to detect MSSA and MRSA nasal colonization in pediatric patients. Depending on the potential clinical impact, culture may be considered as a companion test to improve sensitivity.