[Strategies and recommendations to face respiratory syncytial virus disease in 2024]. / Estrategias y recomendaciones para enfrentar la enfermedad por virus respiratorio sincicial el año 2024.

During the winter of 2023, Chile faced a complex situation related to the respiratory syncytial virus (RSV). After experiencing a decline in RSV circulation during the years of the SARS-CoV-2 pandemic, a late outbreak was observed in the spring of 2022 and an early onset of the outbreak in 2023, with a significant increase in the number of serious cases. The ineffectiveness of strategic planning and risk communication contributed to the complexity of the situation. To avoid the above next winter, measures such as active surveillance, unification of definitions for acute respiratory infections, identification of RSV variants, public education about infections and advance preparation regarding hospital beds and health personnel are suggested. The importance of immunization and intersectoral collaboration to acquire new preventive alternatives is highlighted, as well as the need for early communication about the importance of immunization and identification of high-risk groups, improvement in training of medical personnel and strategic planning of the Ministry of Health. seeking a proactive and collaborative approach to address the complex RSV situation in future winters. The Chilean Immunization Advisory Committee has already carried out an analysis and recommendation on a new prevention alternative. This working group will support any decision of the Ministry of Health in public policies that attempt a change in the paradigm of control of this disease for the health of the children of our country.

Diplodia seriata Biocontrol Is Altered via Temperature and the Control of Bacteria.

Grapevine trunk diseases (GTDs) attack the vine's wood, devastating vineyards worldwide. Chile is the world's fourth-largest wine exporter, and Cabernet Sauvignon is one of the most economically important red wine varieties. Botryosphaeria dieback is an important GTD, and Diplodia seriata is one of the main pathogenic species. Biocontrol studies of these pathogens are commonly carried out at different incubation times but at a single temperature. This study aimed to evaluate the biocontrol effect of Chilean PGPB and grapevine endophytic bacteria against D. seriata at different temperatures. We analyzed the biocontrol effect of Pseudomonas sp. GcR15a, Pseudomonas sp. AMCR2b and Rhodococcus sp. PU4, with three D. seriata isolates (PUCV 2120, PUCV 2142 and PUCV 2183) at 8, 22 and 35 °C. Two dual-culture antagonism methods (agar plug diffusion and double plate) were used to evaluate the in vitro effect, and an in vivo test was performed with Cabernet Sauvignon cuttings. In vitro, the greatest inhibitions were obtained using the agar plug diffusion method and at a temperature of 8 °C, where Rhodococcus sp. PU4 obtains a 65% control (average) and Pseudomonas sp. GcR15a a 57% average. At 22 °C, only strains of Pseudomonas sp. show control. At 35 °C, one Pseudomonas strain shows the highest control (38%), on average, similar to tebuconazole (33%), and then Rhodococcus sp. (30%). In vivo, a biocontrol effect is observed against two D. seriata isolates, while the PUCV 2142 proves to be more resistant to control. The biocontrol ability at low temperatures is promising for effective control in the field, where infections occur primarily in winter.

Different Safety Pattern of an Inactivated SARS-CoV-2 Vaccine (CoronaVac®) According to Age Group in a Pediatric Population from 3 to 17 Years Old, in an Open-Label Study in Chile.

During the COVID-19 pandemic, the importance of vaccinating children against SARS-CoV-2 was rapidly established. This study describes the safety of CoronaVac® in children and adolescents between 3- and 17-years-old in a multicenter study in Chile with two vaccine doses in a 4-week interval. For all participants, immediate adverse events (AEs), serious AEs (SAEs), and AEs of special interest (AESIs) were registered throughout the study. In the safety subgroup, AEs were recorded 28 days after each dose. COVID-19 surveillance was performed throughout the study. A total of 1139 individuals received the first and 1102 the second dose of CoronaVac®; 835 were in the safety subgroup. The first dose showed the highest number of AEs: up to 22.2% of participants reported any local and 17.1% systemic AE. AEs were more frequent in adolescents after the first dose, were transient, and mainly mild. Pain at the inoculation site was the most frequent AE for all ages. Fever was the most frequent systemic AE for 3-5 years old and headache in 6-17 years old. No SAEs or AESIs related to vaccination occurred. Most of the COVID-19 cases were mild and managed as outpatients. CoronaVac® was safe and well tolerated in children and adolescents, with different safety patterns according to age.

Inactivated Vaccine-Induced SARS-CoV-2 Variant-Specific Immunity in Children.

Multiple vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been evaluated in clinical trials. However, trials addressing the immune response in the pediatric population are scarce. The inactivated vaccine CoronaVac has been shown to be safe and immunogenic in a phase 1/2 clinical trial in a pediatric cohort in China. Here, we report interim safety and immunogenicity results of a phase 3 clinical trial for CoronaVac in healthy children and adolescents in Chile. Participants 3 to 17 years old received two doses of CoronaVac in a 4-week interval until 31 December 2021. Local and systemic adverse reactions were registered for volunteers who received one or two doses of CoronaVac. Whole-blood samples were collected from a subgroup of 148 participants for humoral and cellular immunity analyses. The main adverse reaction reported after the first and second doses was pain at the injection site. Four weeks after the second dose, an increase in neutralizing antibody titer was observed in subjects relative to their baseline visit. Similar results were found for activation of specific CD4+ T cells. Neutralizing antibodies were identified against the Delta and Omicron variants. However, these titers were lower than those for the D614G strain. Importantly, comparable CD4+ T cell responses were detected against these variants of concern. Therefore, CoronaVac is safe and immunogenic in subjects 3 to 17 years old, inducing neutralizing antibody secretion and activating CD4+ T cells against SARS-CoV-2 and its variants. (This study has been registered at ClinicalTrials.gov under no. NCT04992260.) IMPORTANCE This work evaluated the immune response induced by two doses of CoronaVac separated by 4 weeks in healthy children and adolescents in Chile. To date, few studies have described the effects of CoronaVac in the pediatric population. Therefore, it is essential to generate knowledge regarding the protection of vaccines in this population. Along these lines, we reported the anti-S humoral response and cellular immune response to several SARS-CoV-2 proteins that have been published and recently studied. Here, we show that a vaccination schedule consisting of two doses separated by 4 weeks induces the secretion of neutralizing antibodies against SARS-CoV-2. Furthermore, CoronaVac induces the activation of CD4+ T cells upon stimulation with peptides from the proteome of SARS-CoV-2. These results indicate that, even though the neutralizing antibody response induced by vaccination decreases against the Delta and Omicron variants, the cellular response against these variants is comparable to the response against the ancestral strain D614G, even being significantly higher against Omicron.

N6 -Methyladenosine Negatively Regulates Human Respiratory Syncytial Virus Replication.

N6-methyladenosine (m6A) is the most abundant internal modification described in eukaryotic mRNA and several viral RNA including human respiratory syncytial virus (HRSV). Here, we evaluated the impact of m6A writers, erasers and readers on HRSV genomic RNA accumulation and inclusion bodies assembly during viral replication. We observed that the METTL3/METTL14 m6A writer complex plays a negative role in HRSV protein synthesis and viral titers, while m6A erasers FTO and ALKBH5 had the opposite effect. We also observed that m6A readers YTHDF1-3 bind to the viral genomic RNA inducing a decrease in its intracellular levels and thus, inhibiting viral replication. Finally, we observed that overexpression of YTHDFs proteins caused a decrease in the size of inclusion bodies (IBs), accompanied by an increase in their number. METTL3 knockdown cells showed an opposite effect indicating that the dynamics of IBs assembly and coalescence are strongly affected by m6A readers in a mechanism dependent on m6A writers. Taken together, our results demonstrated that the m6A modification negatively affects HRSV replication, possibly through a mechanism involving the assembly of inclusion bodies, the main factories of viral genomic RNA synthesis.

Hematologic parameters and biomarkers predictors of severity in Multisystem Inflammatory Syndrome in children associated with SARS-CoV-2. / Parámetros hematológicos y biomarcadores predictores de gravedad en Síndrome Inflamatorio Pediátrico Multisistémico asociado a SARS-CoV-2.

INTRODUCTION: The multisystem inflammatory syndrome in children associated with SARS-CoV-2 (MIS-C) is cha racterized by a hyperinflammatory state resulting from a cytokine storm, evidenced by alterations in laboratory blood testing and acute-phase proteins. OBJECTIVE: to describe the clinical and labora tory characteristics of patients hospitalized due to MIS-C and identify predictive markers of severity. PATIENTS AND METHOD: Retrospective study of 32 patients. The group was divided into critical and non-critical according to clinical presentation and therapy used. Clinical and laboratory aspects were studied, including complete blood count, coagulation tests, and biomarkers. RESULTS: 18/32 were males, with a median age of 6.8 years. The most frequent manifestations were cardiovascular (84.3%), digestive (84%), and mucocutaneous (59%). The group of critical patients included 15 patients, 12 were males with a median age of 8.9 years, and the non-critical group included 17 patients, 6 were males with a median age of 5.4 years. The laboratory parameters at the admission in the global group showed increased C-reactive protein, D-dimer, leukocytes, neutrophils, ferritin, and fibrinogen. In contrast, albumin and blood sodium levels were decreased. At admission, the critical group was cha racterized by presenting thrombocytopenia, hypoalbuminemia, prolonged prothrombin time, and elevated ferritin. At the time of deterioration, there was an intensification of thrombocytopenia, in creased C-reactive protein together with increased neutrophils level. CONCLUSION: The blood count, C-reactive protein, and albuminemia at admission proved to be significantly important in the identi fication of patients at risk of clinical deterioration.

[Recommendations for the suspected diagnosis and management of Multisystemic Inflammatory Syndrome (MIS-C) in the context of a SARS-CoV-2 pandemic. April 2021]. / Recomendaciones para la sospecha diagnóstica y manejo del Síndrome Inflamatorio Multisistémico (SIM-COVID-19) en contexto pandemia SARS-CoV-2. Abril 2021.

Multisystem inflammatory syndrome temporally associated with COVID-19 (MIS-C) is a post-infectious complication described in children and adolescents with previous exposure to SARS-CoV-2. Because of its potential to evolve to severe disease -including cardiovascular impairment and multiple organ failure it requires a prompt diagnosis and appropriate management, including intensive care for most cases. These guidelines compile recent information from scientific literature, from our local clinical experiences during the past pandemic year, and have been discussed by experts. The recommendations provided are meant to help the clinical work of health teams attending the pediatric population.

Recomendaciones para la sospecha diagnóstica y manejo del Síndrome Inflamatorio Multisistémico (SIM-COVID-19) en contexto pandemia SARS-CoV-2. Abril 2021 / Recommendations for the suspected diagnosis and management of Multisystemic Inflammatory Syndrome (MIS-C) in the context of a SARS-CoV-2 pandemic. April 2021

Resumen El síndrome inflamatorio multisistémico asociado a COVID-19 (SIM-COVID-19) es una complicación post-infecciosa descrita en niños y adolescentes con antecedente de exposición a SARS-CoV-2. Su potencial de evolución clínica grave, con compromiso hemodinámico y de falla de múltiples órganos lo convierten en una identidad que requiere de sospecha temprana, rápido diagnóstico y manejo adecuado, incluyendo terapia intensiva en la mayoría de los casos. Las siguientes recomendaciones recopilan información de la literatura científica, de la experiencia nacional en este año de pandemia y han sido consensuadas con expertos. Se presentan como guías de manejo de modo de facilitar el trabajo de equipos de salud a cargo de la atención pediátrica.

Abstract Multisystem inflammatory syndrome temporally associated with COVID-19 (MIS-C) is a post-infectious complication described in children and adolescents with previous exposure to SARS-CoV-2. Because of its potential to evolve to severe disease -including cardiovascular impairment and multiple organ failure it requires a prompt diagnosis and appropriate management, including intensive care for most cases. These guidelines compile recent information from scientific literature, from our local clinical experiences during the past pandemic year, and have been discussed by experts. The recommendations provided are meant to help the clinical work of health teams attending the pediatric population.

Pediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 Treated with Tocilizumab.

We describe a case of Pediatric Inflammatory Multisystem Syndrome temporally associated with SARS-CoV-2 (PIMS-TS) in an 8-year-old child. The patient developed multiorgan dysfunction, including mixed shock, cardiac dysfunction with myocarditis, pneumonia, acute kidney failure, and gastrointestinal involvement characterized by inflammation of the wall of the bowel and pancreatitis. After treatment with Tocilizumab and corticoid therapy, he presented clinical improvement and normalization of inflammatory markers. PIMS-TS is a new disease developed in a small percentage of patients, so a high degree of suspicion is necessary to establish the diagnosis. Supportive care is of paramount importance. The use of Tocilizumab to control the inflammatory response is likely to be beneficial, but the best immunotherapeutic agent has not yet been established. Randomized clinical studies should be run to determine the best treatment.

Compromiso cardiovascular en pacientes con síndrome inflamatorio pediátrico multisistémico, asociado a infección por SARS-CoV-2 / Cardiovascular involvement in pediatric patients with SARS-CoV-2 associated to multisystemic inflammatory syndrome

INTRODUCCION: El Síndrome Inflamatorio Pediátrico Multisistémico (PIMS) ha emergido como una nueva enfermedad en niños, secundaria a infección por SARSCoV-2. Se caracteriza por presentar compromiso multiorgánico con parámetros inflamatorios elevados y manifestaciones clínicas graves, siendo el corazón el órgano más severamente comprometido. OBJETIVO: Describir las características clínicas y de laboratorio de 23 pacientes con diagnóstico de PIMS con compromiso cardiovascular hospitalizados en un centro único. MÉTODO: Se efectuó un estudio retrospectivo analizando los hallazgos clínicos y de laboratorio junto a las manifestaciones cardiovasculares que presentaron estos pacientes. RESULTADOS: 23/29 pacientes con PIMS (78%) presentaron manifestaciones digestivas y mucocutáneas. Las manifestaciones cardiovasculares fueron: Síndrome Kawasaki y "Kawasaki like" sin compromiso coronario en 15/23 (65%) y con compromiso coronario en 3 (13%). Shock en 9 pacientes (39%), injuria miocárdica- miocarditis en 8 (35%) y derrame pericárdico en 13 (56%). Trastornos del ritmo cardíaco se observaron en 6 pacientes (26%). La terapia más utilizada fue inmunoglobulina y corticoides. 18 /23 requirieron manejo en unidades de intermedio y/o intensivo. Un 70% de los pacientes se recuperó del compromiso cardiovascular antes del alta. CONCLUSIÓN: El compromiso cardiovascular en PIMS es la complicación más frecuente de esta enfermedad, que se acompaña de manifestaciones inmunológicas y hematológicas graves lo que hace necesario un tratamiento multidisciplinario para un mejor manejo de estos pacientes.

INTRODUCTION: Pediatric Multisystemic Inflammatory Syndrome (PIMS) has emerged as a new disease in children, secondary to SARSCoV-2 infection. It is characterized by multi-organ involvement with elevated inflammatory parameters and severe clinical manifestations, the heart being the organ most severely involved. OBJETIVE: to describe the clinical and laboratory characteristics of 23 patients diagnosed with PIMS with cardiovascular involvement hospitalized in a single center. METHOD: We conducted a retrospective study in which we analyzed the clinical and laboratory findings along with the cardiovascular manifestations presented by these patients. Results: 23/29 patients with PIMS and cardiovascular involvement were selected, 78% had digestive and mucocutaneous manifestations. Cardiovascular manifestations consisted of KawasakiKawasaki like syndrome without coronary involvement in 15/23 (65%) and coronary involvement in 3 (13%). Nine patients developed shock (39%), 8 (35%) myocardial injury in and 13 (56%) pericardial effusion.. Heart rhythm disorders were observed in 6 patients (26%). The main therapy was immunoglobulin and corticosteroids. 18 /23 required management in intermediate and/or intensive care unit. 70% of patients recovered from cardiovascular involvement before discharge. CONCLUSION: Cardiovascular involvement in PIMS is the most frequent complication of this disease, but it is associated with severe immunological and hematological manifestations, which makes necessary a multidisciplinary treatment for a better management

Espectro clínico de la infección en niños por virus SARS-CoV-2 en un centro de referencia pediátrico en plena pandemia. Reporte del Comité Clínico COVID, Hospital de Niños Roberto del Río, Santiago Chile

Resumen Introducción: La infección por virus SARS-CoV-2 responsable de la pandemia actual, es una entidad clínica y fisiopatológica nueva y en desarrollo, cuyo control aún es incierto mientras no contemos con una vacuna efectiva y de distribución universal. Descrita inicialmente como una enfermedad respiratoria mayoritariamente de adultos, los niños también pueden enfermar y se ha visto que en ellos las manifestaciones clínicas de enfermedad suelen diferir a las de los adultos expresándose como cuadros benignos en su mayoría. Si requieren hospitalización o algún tipo de asistencia, el cuadro se resuelve con tratamiento de soporte y sin complicaciones, mayoritariamente. Sin embargo, en el síndrome inflamatorio multisistémico asociado a COVID-19 (SIM-C) es de vital importancia la sospecha precoz y la derivación a un centro de alta complejidad para otorgar el soporte y tratamiento adecuado para lograr una buena y adecuada sobrevida. Objetivo: Describir el espectro clínico de enfermedad por virus SARS-CoV-2 en un centro de referencia pediátrico con la pandemia aún en desarrollo. Método: Se presenta la casuística de 537 pacientes con infección por SARS-CoV-2 atendidos entre marzo 1 y julio 15, 2020, con descripción de aquellos que fueran hospitalizados. Resultados: 127 (23%) de ellos fueron internados y de éstos 69% sintomáticos. Veintiséis pacientes (20%) de los hospitalizados presentaron SIM-C y sólo uno falleció por complicaciones de sus patologías de base.

Abstract Background: SARS-CoV-2 virus infection responsible for de pandemic in course, is a new clinical and physiopathological entity, whose control is still uncertain till we can provide an effective and universal vaccine. In the beginning it was described as a respiratory disease which affects mainly adults, children can have the disease too and in this group the disease can be different than the adult disease. Acute infection in children is mostly mild and when it requires hospital assistance it resolves with support therapy and without complications most of the time. However, in the Pediatric Inflammatory Multisystemic Syndrome is vital the early clinical suspect and refers to a tertiary center to bring support and properly treatment. Aim: To describe the clinical spectrum of SARS-CoV-2 virus disease in a pediatric referral center with the pandemic still in development. Method: A case series of 537 patients with SARS-CoV-2 infection treated between March 1 and July 15, 2020 is presented with a description of those who were hospitalized. Results: 127 (23%) of them were hospitalized and of these 69% were symptomatic. Twenty-six patients (20%) of those hospitalized presented PIMS, only one died for complications of his chronic diseases.

Multisystem inflammatory syndrome in children (MIS-C): Report of the clinical and epidemiological characteristics of cases in Santiago de Chile during the SARS-CoV-2 pandemic.

OBJECTIVE: To describe the clinical and epidemiological characteristics of hospitalized children with multisystem inflammatory syndrome in children (MIS-C) in Santiago, Chile. METHODS: This was an observational study of children with MIS-C (May 1 to June 24, 2020), in three pediatric hospitals in Santiago. Demographic characteristics and epidemiological data, medical history, laboratory tests, cardiology evaluations, treatment, and clinical outcomes were analyzed. RESULTS: Twenty-seven patients were admitted (median age 6, range 0-14 years). Sixteen of the 27 (59%) required intensive care unit admission; there were no deaths. Seventy-four percent had no comorbidities, and the median number of days of symptoms before admission was 4 (range 2-9 days). Gastrointestinal symptoms were the most frequent, and inflammatory markers were increased at admission. A recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was detected in 82% of cases. The severe group showed significantly lower hemoglobin and albumin levels, decreased platelet counts, and higher d-dimer during disease evolution. Echocardiography showed abnormalities (myocardial, pericardial, or coronary) in 12 patients (46%) during their hospital stay. Anti-inflammatory treatment (immunoglobulin and/or corticosteroids) was prescribed in 24 patients. MIS-C appeared in clusters weeks after the peak of SARS-CoV-2 cases, especially in the most vulnerable areas of Santiago. CONCLUSIONS: This study describes the first series (n = 27) of children with MIS-C in a Latin American country, showing favorable clinical outcomes. Education and alerts are required for clinical teams to establish an early diagnosis and prompt treatment.

Infecciones respiratorias virales en episodios de fiebre en niños con trasplante de precursores hematopoyéticos / Respiratory viral infections during episodes of fever in children undergoing hematopoietic stem cell transplantation

Resumen Introducción: Los niños que reciben trasplante de precursores hematopoyéticos (TPH) pueden presentar infecciones respiratorias virales (IRV) durante episodios febriles. Los datos sobre su evolución clínica son escasos, así como la comparación de ellos con infecciones bacterianas (IB). Objetivo: Caracterizar la evolución clínica de pacientes con IRV, en comparación con IB en niños con TPH, cursando un episodio febril. Método: Estudio prospectivo en pacientes ≤ 18 años con cáncer y TPH ingresados por fiebre en el Hospital Luis Calvo Mackenna (2016-2019). Se realizó evaluación clínica y de laboratorio: hemocultivos, RPC para patógenos respiratorios (Filmarray®), cuantificación viral y medición de citoquinas en muestra nasal (Luminex®, 38 citoquinas). Se compararon los grupos IRV, IB y los de etiología no precisada (ENP) en relación con: infección respiratoria aguda (IRA), citoquinas nasales, ingreso a UCI, necesidad de ventilación mecánica, mortalidad y suspensión de antimicrobianos. Resultados: De 56 episodios febriles, 35 fueron IRV, 12 IB y 9 de ENP. Mediana de edad fue 8,5 años, 62% masculino. Un 94% de los casos IRV presentó IRA sintomática, versus 33% en los grupos IB y ENP (p < 0,001), con IRA baja en 69% de las IRV (p < 0,001). Rinovirus (54%) y coronavirus (15%) fueron las etiologías más frecuentemente detectadas. No hubo diferencias en citoquinas nasales entre los grupos IRV e IB. Ingreso a UCI: 11% del grupo IRV, 17% de IB y 11% de ENP (p = 0,88). Requirieron ventilación mecánica sólo 2 pacientes (p = 0,37) sin fallecimiento. Tras la detección viral respiratoria por RPC, se suspendió antimicrobianos en 26% de los casos con IRV (p = 0,04). Conclusión: Las IRV son frecuentes en niños con TPH y episodios febriles. La detección viral podría optimizar y racionalizar el uso de antimicrobianos en esta población.

Abstract Background: Children undergoing hematopoietic stem cell transplant (HSCT) can develop respiratory viral infections (RVI) during fever episodes. There are few data about clinical outcomes in RVI and compared to bacterial infections (BI) in this population. Aim: To determine clinical outcome of RVI, compared to BI in children with HSCT. Methods: Prospective study, patients ≤ 18 years with cancer and HSCT admitted with fever at a National Bone Marrow Transplant Center (Hospital Calvo Mackenna), Chile, (April-2016 to May-2019). Clinical assessment, laboratory tests, blood cultures, nasopharyngeal sample for multiplex-PCR (Filmarray®), viral loads by PCR and cytokine panel (Luminex®, 38 cytokines) were performed. The following outcomes were evaluated: upper/lower respiratory tract disease (RTD), admission to ICU, mechanical ventilation, mortality and antimicrobial withdrawal. Results: Of 56 febrile episodes, 35 (63%) were RVI, 12 (21%) BI and 9 (16%) with unknown etiology (UE). Median of age was 8.5 years, 62% male gender. Rhinovirus (54%) and coronavirus (15%) were the more frequent detected viruses. No significant differences in cytokine levels were observed between RVI and BI. 94% of RVI patients had symptomatic RTD, versus 33% in BI and 33% in UE group (p < 0.001), with lower-RTD in 69% of RVI group (p < 0,001). Admission to ICU was 11% in RVI, 17% in BI and 11% in UE group (p = 0.88); only 2 patients required mechanical ventilation (p = 0.37) and no mortality was reported. After an RVI was detected by PCR, antimicrobials were withdrawal in 26% of patients with RVI (p: 0.04). Conclusion: RVI are frequent etiologic agents in febrile episodes of patients with HSCT. Viral detection might help to rationalize the use of antimicrobials in this population.

[Respiratory viral infections during episodes of fever in children undergoing hematopoietic stem cell transplantation]. / Infecciones respiratorias virales en episodios de fiebre en niños con trasplante de precursores hematopoyéticos.

BACKGROUND: Children undergoing hematopoietic stem cell transplant (HSCT) can develop respiratory viral infections (RVI) during fever episodes. There are few data about clinical outcomes in RVI and compared to bacterial infections (BI) in this population. AIM: To determine clinical outcome of RVI, compared to BI in children with HSCT. METHODS: Prospective study, patients ≤ 18 years with cancer and HSCT admitted with fever at a National Bone Marrow Transplant Center (Hospital Calvo Mackenna), Chile, (April-2016 to May-2019). Clinical assessment, laboratory tests, blood cultures, nasopharyngeal sample for multiplex-PCR (Filmarray®), viral loads by PCR and cytokine panel (Luminex®, 38 cytokines) were performed. The following outcomes were evaluated: upper/lower respiratory tract disease (RTD), admission to ICU, mechanical ventilation, mortality and antimicrobial withdrawal. RESULTS: Of 56 febrile episodes, 35 (63%) were RVI, 12 (21%) BI and 9 (16%) with unknown etiology (UE). Median of age was 8.5 years, 62% male gender. Rhinovirus (54%) and coronavirus (15%) were the more frequent detected viruses. No significant differences in cytokine levels were observed between RVI and BI. 94% of RVI patients had symptomatic RTD, versus 33% in BI and 33% in UE group (p < 0.001), with lower-RTD in 69% of RVI group (p < 0,001). Admission to ICU was 11% in RVI, 17% in BI and 11% in UE group (p = 0.88); only 2 patients required mechanical ventilation (p = 0.37) and no mortality was reported. After an RVI was detected by PCR, antimicrobials were withdrawal in 26% of patients with RVI (p: 0.04). CONCLUSION: RVI are frequent etiologic agents in febrile episodes of patients with HSCT. Viral detection might help to rationalize the use of antimicrobials in this population.

[Clinical manifestations of SARS-CoV-2 infection in children in the middle of pandemic season in a pediatric tertiary center. Report of local COVID Clinical Committee, Hospital de Niños Roberto del Río, Santiago Chile]. / Espectro clínico de la infección en niños por virus SARS-CoV-2 en un centro de referencia pediátrico en plena pandemia. Reporte del Comité Clínico COVID, Hospital de Niños Roberto del Río, Santiago Chile.

BACKGROUND: SARS-CoV-2 virus infection responsible for de pandemic in course, is a new clinical and physiopathological entity, whose control is still uncertain till we can provide an effective and universal vaccine. In the beginning it was described as a respiratory disease which affects mainly adults, children can have the disease too and in this group the disease can be different than the adult disease. Acute infection in children is mostly mild and when it requires hospital assistance it resolves with support therapy and without complications most of the time. However, in the Pediatric Inflammatory Multisystemic Syndrome is vital the early clinical suspect and refers to a tertiary center to bring support and properly treatment. AIM: To describe the clinical spectrum of SARS-CoV-2 virus disease in a pediatric referral center with the pandemic still in development. METHOD: A case series of 537 patients with SARS-CoV-2 infection treated between March 1 and July 15, 2020 is presented with a description of those who were hospitalized. RESULTS: 127 (23%) of them were hospitalized and of these 69% were symptomatic. Twenty-six patients (20%) of those hospitalized presented PIMS, only one died for complications of his chronic diseases.

Intravenous palivizumab in respiratory syncytial virus infection after hematopoietic stem cell transplant in children.

Respiratory syncytial virus (RSV) infection can cause lower respiratory tract disease and mortality in pediatric hematopoietic stem cell transplant (HSCT) recipients. We report two children who underwent HSCT and developed RSV infection simultaneously at the Bone Marrow Transplant Unit. The treatment with intravenous palivizumab was provided and sequential viral loads were measured in nasopharyngeal (NP) and whole blood samples. To our knowledge, this is the first report where RSV loads were measured in parallel (NP and blood), before and after palivizumab, in correlation with a favorable clinical outcome in both cases.

Genomic Loads and Genotypes of Respiratory Syncytial Virus: Viral Factors during Lower Respiratory Tract Infection in Chilean Hospitalized Infants.

The clinical impact of viral factors (types and viral loads) during respiratory syncytial virus (RSV) infection is still controversial, especially regarding newly described genotypes. In this study, infants with RSV bronchiolitis were recruited to describe the association of these viral factors with severity of infection. RSV antigenic types, genotypes, and viral loads were determined from hospitalized patients at Hospital Roberto del Río, Santiago, Chile. Cases were characterized by demographic and clinical information, including days of lower respiratory symptoms and severity. A total of 86 patients were included: 49 moderate and 37 severe cases. During 2013, RSV-A was dominant (86%). RSV-B predominated in 2014 (92%). Phylogenetic analyses revealed circulation of GA2, Buenos Aires (BA), and Ontario (ON) genotypes. No association was observed between severity of infection and RSV group (p = 0.69) or genotype (p = 0.87). After a clinical categorization of duration of illness, higher RSV genomic loads were detected in infants evaluated earlier in their disease (p < 0.001) and also in infants evaluated later, but coursing a more severe infection (p = 0.04). Although types and genotypes did not associate with severity in our children, higher RSV genomic loads and delayed viral clearance in severe patients define a group that might benefit from new antiviral therapies.

Infecciones respiratorias agudas bajas: descripción de los egresos del hospital Roberto del Río en el año 2016 / Acute respiratory infections low: description of the discharges of the hospital Roberto del Río in 2016

Las infecciones respiratorias agudas bajas (IRAB) son la principal causa de hospitalización en lactantes, y una de las principales causas de muerte de niños entre un mes y 4 años. Constituyen un problema de salud pública durante los meses de otoño e invierno, con una sobredemanda de atención en los servicios de urgencia y requerimiento de camas en los distintos centros hospitalarios, guardando este fenómeno directa relación con la epidemia del virus respiratorio sincicial (VRS), el principal agente etiológicoi-ii. En los últimos años se han implementado una serie de medidas que han permitido desarrollar un mejor manejo de las IRAB, como el uso de nuevos esquemas de vacunación, la disminución del uso irracional de antibióticos, la implementación de salas IRA en atención primaria para el manejo de las infecciones respiratoriasiii, uso de protocolos actualizados para manejo de patología respiratoriaiv, aumento del recurso humano durante la campaña de invierno en los servicios públicos de salud, y avances en infraestructura. Los virus son la principal causa de IRAB, siendo el VRS el más frecuente, seguido por rinovirus, virus influenza, parainfluenza, metapneumovirus, y adenovirus. Éste último, hasta hace algunos años era la segunda causa viral de IRAB, importante agente en infecciones asociadas a la atención en salud y causa de secuelas respiratorias en muchos casosv-vi. Esto pone de manifiesto la importancia de determinar la etiología de las IRAB en pacientes hospitalizados, más cuando la clínica e imagenología no permiten diferenciarlos. Conocer la etiología condicionará medidas terapéuticas a tomar, necesidad de aislamiento, y seguimiento de casos especiales. Esto cobra particular importancia en los lactantes, quienes por presentar un menor desarrollo de la vía respiratoria e inmadurez inmunológica, tienen las más altas tasas de hospitalización y padecen los cuadros más gravesvii. De acuerdo a datos del Departamento de Estadísticas e Información de Salud (DEIS) del año 2011, las infecciones respiratorias fueron la principal causa de egresos hospitalarios de niños y adolescentes en el país con un 21,7% del total. Específicamente en el Hospital Roberto del Rio la situación fue similar, correspondiendo a un 33,3% de las altas. En el siguiente reporte se describen las características de las infecciones respiratorias agudas bajas de niños y adolescentes egresados del Hospital Roberto del Río a lo largo del año 2016.

Lower respiratory tract infections (LRTI) are the main cause of outpatient visits during cold months and hospitalization in infants. Through an observational, descriptive study, we analyzed the medical attentions at the Emergency Department (ED) and the hospitalizations occurred during 2016 in Hospital Roberto del Río. We included demographic variables, date of admission, diagnosis at discharge, etiologic agent and requirement of intensive care unit. Respiratory infections were the main cause of outpatient visits to the ED, being 21.7%. They are also the major cause of hospital discharge (1,856 cases, 23.8% of total). 61% of hospitalized cases were male, ant the mail affected group was those under 2 years of age (74.4%). In 93% of cases with detected etiological agent, a virus was found, 57, 9% being respiratory syncytial virus. Sixty nine percent of admission occurred during June and September and 15, 2% patients were admitted to the intensive care unit. We hope the current data helps policy maker in further years.

Enhanced antimicrobial activity of a peptide derived from human lysozyme by arylation of its tryptophan residues.

Antimicrobial peptides are valuable agents to fight antibiotic resistance. These amphipatic species display positively charged and hydrophobic amino acids. Here, we enhance the local hydrophobicity of a model peptide derived from human lysozyme (107RKWVWWRNR115) by arylation of its tryptophan (Trp) residues, which renders a positive effect on Staphylococcus aureus and Staphylococcus epidermidis growth inhibition. This site-selective modification was accessed by solid-phase peptide synthesis using the non-proteinogenic amino acid 2-aryltryptophan, generated by direct C-H activation from protected Trp. The modification brought about a relevant increase in growth inhibition: S. aureus was fully inhibited by arylation of Trp 112 and by only 10% by arylation of Trp 109 or 111, respect to the non-arylated peptide. On the other hand, S. epidermidis was fully inhibited by the three arylated peptides and the parent peptide. The minimum inhibitory concentration was significantly reduced for S. aureus depending on the arylation site.