Shedding of infectious SARS-COV-2 in two asymptomatic children / Excreción de SARS-CoV-2 infeccioso en dos niños asin tomáticos

Abstract Asymptomatic infections with SARS-CoV-2 are associ ated with viral transmission and have a key role in the propagation of the pandemic. Understanding viral shed ding during asymptomatic infections is critical. Unfor tunately, data on asymptomatic SARS-CoV-2 infection in children is extremely limited. To determine the presence of viral viable shedding, we prospectively followed two healthy children of a family where both parents devel oped mild COVID-19 (April 2021). SARS-CoV-2 detection was made by RT-PCR and virus isolation by cell culture from saliva samples. Positive samples were sequenced to identify variants of SARS-CoV-2. Serum samples were evaluated to determine the presence of antibodies using a single enzyme-linked immunosorbent assay (ELISA, COVIDAR IgG). Both children were SARS-CoV-2 positive and asymptomatic. In addition, the virus grew in cell cul ture from saliva samples. Furthermore, one child showed viable SARS-CoV-2 for at least 17 days after the onset symptoms from his father. The recommended isolation period for asymptomatic contacts during the acquisition of data had been established for 10 days; however, this child remained with viable virus beyond that period. The positive samples from both children were consistent with B.1.1.28.1 lineage (Gamma). In both asymptomatic children, anti-Spike IgG was detected. Asymptomatic children may represent a source of infection that should not be underestimated during this pandemic.

Resumen Las infecciones asintomáticas por SARS-CoV-2 están asociadas a la transmisión viral y tienen un papel cla ve en la propagación de la pandemia. Comprender la excreción viral durante las infecciones asintomáticas es fundamental. Desafortunadamente, los datos sobre la infección asintomática por SARS-CoV-2 en niños son extremadamente limitados. Para determinar la presencia de excreción de virus viable, se siguió prospectivamente a dos niños sanos de una familia en la que ambos padres desarrollaron COVID-19 leve (abril 2021). La detección de SARS-CoV-2 se realizó por RT-PCR y el aislamiento del virus por cultivo celular a partir de muestras de saliva. Las muestras positivas se secuenciaron para identificar variantes de SARS-CoV-2. En las muestras de suero se determinó la presencia de anticuerpos utilizando un ensayo de ELISA (COVIDAR IgG). Ambos niños fueron positivos para SARS-CoV-2 y asintomáticos. Además, el virus creció en cultivos celulares a partir de muestras de saliva. Uno de los niños mantuvo SARS-CoV-2 via bles durante al menos 17 días después de la aparición de los síntomas de su padre. El período de aislamiento recomendado para contactos asintomáticos durante la adquisición de datos se había establecido en 10 días, sin embargo, este niño permaneció con virus viable más allá de ese período. Las muestras positivas de estos niños correspondieron al linaje B.1.1.28.1 (Gamma). En ambos niños asintomáticos se detectó anticuerpos IgG anti-Spike. Concluimos que los niños asintomáticos pueden representar una fuente de infección que no debe subestimarse durante esta pandemia.

Characteristics of viral shedding in people infected with SARS-CoV-2 during difference stages / 中国热带医学

@#Abstract: Viral shedding of SARS-CoV-2 is a continuous dynamic process, which can be divided into latent stage, initial stage, peak stage and decreasing stage according to the characteristics of viral shedding. After being infected with SARS-CoV-2, the infected person generally stays in the latent period for 1-3 days, which is characterized by continuous negative nucleic acid test results and no infectiousness, and the risk of infection for close contacts is very low. At the initial stage of viral shedding is characterized by a rapid decline in the Ct value of nucleic acid tests in a short time, and clinical symptoms gradually appear. The infectiousness of the infected person gradually increases during this period, and the risk of infection for close contacts also gradually increases, but it is still in the early stage of infection, the possibility of viral shedding is low, and the risk of infection of secondary close contacts is low. The peak of viral shedding is characterized by low Ct value in nucleic acid test and obvious clinical symptoms; during this period, the infected person is the most infectious, and the risk of infection of the contact is the highest, so the scope of close contacts should be expanded appropriately. The decreasing period is characterized by the gradual increase of Ct value of nucleic acid test and the gradual disappearance of clinical symptoms; during this period, the infectiousness of the infected person gradually decreases to disappear. In an outbreak, an infected person in the decreasing phase is more likely to be an early infected person in the transmission chain. If infected individuals in the decreasing phase are found in an area without a SARS-CoV-2 epidemic, it suggests that the local outbreak epidemic has been spreading for some time and may be larger in scale. According to the characteristics of viral shedding, risk personnel can be determined more scientifically and accurately, so as to minimize the risk and reduce the waste of epidemic prevention resources.

¿Cuál es el período de excreción viral e infectividad de la variante Ómicron del virus SARS-CoV-2?: reporte breve de evidencia / What is the period of viral shedding and infectivity of the omicron variant of Sars-cov-2 virus?: brief report of evidence

ANTECEDENTES Y OBJETIVO Han pasado 2 años y medio desde que la Organización Mundial de la Salud decretó emergencia sanitaria por la pandemia ocasionada por SARS-CoV-2. Durante este tiempo, se han presentado una serie de desafíos para evitar su propagación, uno de ellos corresponde a las mutaciones y cambios que ha sufrido el virus. En noviembre de 2021 se notificó la variante Ómicron B.1.1.529, que presenta algunas mutaciones de preocupación, asociándose con mayor transmisibilidad y menor susceptibilidad a los anticuerpos neutralizantes. En este contexto la Jefatura de la División de Planificación Sanitaria solicita este reporte breve de evidencia con el objetivo de conocer el período de excreción viral e infectividad de la variante Ómicron. METODOLOGÍA Se buscaron revisiones sistemáticas que respondieron la pregunta en las bases de datos MEDLINE y EMBASE a través de OVID y en Epistemonikos, con fecha 30 de agosto 2022. Debido a no encontrarse evidencia en los motores de búsqueda seleccionados, se realizó una búsqueda en Google académico, sin embargo, tampoco fue identificada evidencia alguna. Se incluyen revisiones sistemáticas, estudios que describieron o midieran los períodos de infectividad y excreción de la variante Ómicron del virus SARS-CoV-2. Se excluyen períodos de infectividad y excreción de otras variantes del Virus SARS-CoV-2. RESULTADOS -No se encontró evidencia que describiera el periodo de infectividad y excreción del virus en personas contagiadas con SARS-COV-2 variante Ómicron.

Poor Respiratory Health Following Relapsing SARS-CoV-2 Infection in Children with Cystic Fibrosis

Children with cystic fbrosis (CF) constitute a high-risk group for COVID-19 with underlying chronic lung disease. COVID19 severity varying from mild infection to need of intensive care has been described in children with CF. Two children with signifcant underlying pulmonary morbidity are described here, who developed severe disease following SARS-CoV-2 infection. Case 1 (a 9-y-old boy) had pneumonia with respiratory failure requiring noninvasive ventilation support. He had delayed clearance of SARS-CoV-2, with recurrence of symptomatic disease with short asymptomatic period in between. He was also diagnosed with CF-related diabetes and allergic bronchopulmonary aspergillosis during the second episode. Case 2 (an 18-mo-old boy) had two episodes of SARS-CoV-2–related severe lower respiratory infection within a period of 2 mo, requiring high-fow nasal oxygen support. Both children had 3rd pulmonary exacerbation but SARS-CoV-2 was not detected in respiratory secretions. To conclude, children with CF with underlying pulmonary morbidity, can develop severe COVID-19 and prolonged SARS-CoV-2 shedding.

Development and validation of an individualized nomogram for early prediction of the duration of SARS-CoV-2 shedding in COVID-19 patients with non-severe disease / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

With the number of cases of coronavirus disease-2019 (COVID-19) increasing rapidly, the World Health Organization (WHO) has recommended that patients with mild or moderate symptoms could be released from quarantine without nucleic acid retesting, and self-isolate in the community. This may pose a potential virus transmission risk. We aimed to develop a nomogram to predict the duration of viral shedding for individual COVID-19 patients. This retrospective multicentric study enrolled 135 patients as a training cohort and 102 patients as a validation cohort. Significant factors associated with the duration of viral shedding were identified by multivariate Cox modeling in the training cohort and combined to develop a nomogram to predict the probability of viral shedding at 9, 13, 17, and 21 d after admission. The nomogram was validated in the validation cohort and evaluated by concordance index (C-index), area under the curve (AUC), and calibration curve. A higher absolute lymphocyte count (

Viral shedding in day-care children and students infected with norovirus in outbreaks / 上海预防医学

Objective:This study aimed to investigate the time duration of norovirus shedding among day-care children and students during norovirus outbreaks， as well as influencing factors affecting the viral shedding. Methods:Suspected cases of norovirus infection and their close contacts were collected from child care and school settings during norovirus outbreaks in Xuhui District， Shanghai， from 2017 through 2019. Specimens were detected using real-time RT-PCR to determine whether children had been infected with norovirus. Subsequently， further specimens were collected every 3-7 days from infected children until specimens tested negative for norovirus. Results:A total of 76 outbreaks were reported involving 1 014 suspected cases. In the 421 suspected cases， 311 confirmed cases were diagnosed after examination. Furthermore， a total of 58 confirmed cases participated in this study with informed consent， with a participation rate of 18.65%. The average time duration of norovirus shedding was （16.24±13.80） days， in which 79.31% had viral shedding more than 7 days， 37.93% more than 14 days and 17.24% more than 21 days. A Cox proportional-hazards model showed that children with more severe symptoms （HR=2.06，P=0.040）， day-care children （HR=4.13，P=0.012）， and confirmed cases in 2019 （HR=0.11，P<0.001） had longer duration of viral shedding. Conclusion:Children may remain shedding norovirus after their recovery and back to class. Improvement in sanitation for these recovered children in child care and schools is especially necessary， which may avert secondary transmission.

Characterisation of genotype VII Newcastle disease virus (NDV) isolated from NDV vaccinated chickens, and the efficacy of LaSota and recombinant genotype VII vaccines against challenge with velogenic NDV

A Newcastle disease virus (NDV) isolate designated IBS002 was isolated from a commercial broiler farm in Malaysia. The virus was characterised as a virulent strain based on the multiple basic amino acid motif of the fusion (F) cleavage site 112RRRKGF117 and length of the C-terminus extension of the hemagglutinin-neuraminidase (HN) gene. Furthermore, IBS002 was classified as a velogenic NDV with mean death time (MDT) of 51.2 h and intracerebral pathogenicity index (ICPI) of 1.76. A genetic distance analysis based on the full-length F and HN genes showed that both velogenic viruses used in this study, genotype VII NDV isolate IBS002 and genotype VIII NDV isolate AF2240-I, had high genetic variations with genotype II LaSota vaccine. In this study, the protection efficacy of the recombinant genotype VII NDV inactivated vaccine was also evaluated when added to an existing commercial vaccination program against challenge with velogenic NDV IBS002 and NDV AF2240-I in commercial broilers. The results indicated that both LaSota and recombinant genotype VII vaccines offered full protection against challenge with AF2240-I. However, the LaSota vaccine only conferred partial protection against IBS002. In addition, significantly reduced viral shedding was observed in the recombinant genotype VII-vaccinated chickens compared to LaSota-vaccinated chickens.