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.

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.

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.

Emerging Resistance Trends in Viridans Group Streptococci Bloodstream Infections Among Immunocompromised Children Receiving Levofloxacin Prophylaxis.

BACKGROUND: Levofloxacin prophylaxis (LVXp) is often used for patients with underlying leukemia and severe neutropenia to reduce the risk of fever and bacteremia. This study evaluated trends in viridans group streptococci (VGS) antibiotic susceptibilities over time and clinical outcomes of children with VGS bloodstream infections (BSIs) during institutional adoption of LVXp. METHODS: VGS blood culture isolates between 1/1/2010 and 12/31/2021 with susceptibility testing reported were included. Available isolates were re-identified to the species level and additional susceptibility testing was performed. Demographic and clinical data were abstracted from medical records. RESULTS: A total of 264 VGS BSI isolates were identified in immunocompromised (IC, n = 125) and non-immunocompromised subjects, (non-IC, n = 139). IC subjects had lower rates of VGS isolates susceptible (S) to LVX and higher minimum inhibitory concentration (MICs) to LVX (p = 0.004) and ciprofloxacin (p = 0.0005) compared with non-IC subjects. No other evaluated antibiotic had increased MICs in either group. Fifteen of 19 (74%) LVX not susceptible (NS) isolates occurred in IC subjects, 13 represented breakthrough infections. IC subjects had higher rates of VGS-related shock (p = 0.012), need for pressor support (p = 0.039), and longer duration of hospitalization than non-IC subjects (p < 0.001). Clinical outcomes were comparable between subjects with LVX S and NS VGS BSI isolates. CONCLUSIONS: VGS with reduced susceptibility to LVX emerged during institutional adoption of LVXp in high-risk children with immunocompromising conditions, but did not result in significant differences in clinical outcomes. Ongoing surveillance and susceptibility testing are critical in weighing the utility of LVXp against emerging antimicrobial resistance in this high-risk population.