MUC5AC: A potential biomarker of severity in pediatric patients infected with influenza.

Numerous factors can increase the risk of severe influenza; however, a majority of severe cases occur in previously healthy children. Identification of high-risk children is important for targeted preventive interventions and prompt treatment. The aim of this study was to evaluate MUC5AC as a biomarker for influenza disease severity in children. For this, a prospective cohort study was conducted in 2019. Children hospitalized with acute respiratory infection (ARI) with confirmed positive influenza infection were enrolled. Influenza cases were identified by reverse transcriptase-polymerase chain reaction. Life-threatening disease (LTD) was defined by the need for intensive care and ventilatory support. MUC5AC, epidemiologic, and clinical risk factors were assessed. Three hundred and forty-two patients were hospitalized with ARI, of which 49 (14%) had confirmed influenza infection and 6 (12%) of them developed LTD. MUC5AC levels were higher in those patients with mild disease compared to cases with poorer outcomes. Our results show that the severity of influenza infection in children is significantly associated with low levels of MUC5AC. These findings suggest its potential as a suitable biomarker for predicting disease severity.

Serum Vitamin D Levels and Life-Threatening Respiratory Syncytial Virus Infection in Previously Healthy Infants.

BACKGROUND: 25-hydroxyvitamin D (VD) effects on lung function and immune-modulation might affect respiratory syncytial virus (RSV) infection outcomes. We aimed to assess VD levels on admission and their association with life-threatening RSV disease (LTD). METHODS: A prospective cohort study was conducted during 2017-2019. Previously healthy infants aged <12 months, hospitalized with a first episode of RSV infection, were enrolled. LTD was defined by need for intensive care and ventilatory support. Serum VD levels <20 ng/mL were categorized as deficient, and 20-29.9 ng/mL as insufficient. RESULTS: Of 125 patients studied, 73 (58%) were male. Median age was 4 months. Twenty-two patients developed LTD. No differences in viral load were seen between cases with LTD and controls (P = .94). Patients who developed LTD had significantly lower VD levels: median 18.4 ng/mL (IQR, 15.1-26.9 ng/mL) versus 31.7 ng/mL (IQR, 23.6-42.0 ng/mL), P < .001; 59% of infants with LTD had VD deficiency compared with 12% in those with better outcome. Multivariable regression analysis confirmed VD deficiency as a risk factor (odds ratio, 11.83; 95% confidence interval, 3.89-35.9; P < .001). CONCLUSIONS: These findings provide additional evidence for the development of strategies to prevent severe RSV infections.

Acute flaccid myelitis: cause, diagnosis, and management.

Acute flaccid myelitis (AFM) is a disabling, polio-like illness mainly affecting children. Outbreaks of AFM have occurred across multiple global regions since 2012, and the disease appears to be caused by non-polio enterovirus infection, posing a major public health challenge. The clinical presentation of flaccid and often profound muscle weakness (which can invoke respiratory failure and other critical complications) can mimic several other acute neurological illnesses. There is no single sensitive and specific test for AFM, and the diagnosis relies on identification of several important clinical, neuroimaging, and cerebrospinal fluid characteristics. Following the acute phase of AFM, patients typically have substantial residual disability and unique long-term rehabilitation needs. In this Review we describe the epidemiology, clinical features, course, and outcomes of AFM to help to guide diagnosis, management, and rehabilitation. Future research directions include further studies evaluating host and pathogen factors, including investigations into genetic, viral, and immunological features of affected patients, host-virus interactions, and investigations of targeted therapeutic approaches to improve the long-term outcomes in this population.

Acute Flaccid Myelitis Associated with Enterovirus D68 in Children, Argentina, 2016.

After a 2014 outbreak of severe respiratory illness caused by enterovirus D68 in the United States, sporadic cases of acute flaccid myelitis have been reported worldwide. We describe a cluster of acute flaccid myelitis cases in Argentina in 2016, adding data to the evidence of association between enterovirus D68 and this polio-like illness.

Adolescent Tuberculosis: 6 Years of Experience in a Tertiary Care Pediatric Hospital in Buenos Aires, Argentina.

INTRODUCTION: Adolescence is a key risk period for tuberculosis disease and its adverse outcomes. This group commonly develops infectious forms of tuberculosis and has a wider range of social contacts outside the household. There are few specific data on the behavior of tuberculosis disease in this population. METHODS: A total of 292 patients 10-19 years of age with tuberculosis between January 2016 and December 2021 were retrospectively analyzed in the Department of Phthisiology of the Children's Hospital "Dr. Ricardo Gutiérrez" of Buenos Aires, Argentina. RESULTS: The median patient age was 14 years (interquartile range 12-16). Most patients were previously healthy, and 55% were unaware of the source of the infection. However, 75% sought medical advice owing to the presence of symptoms, with hemoptysis and weight loss being most frequent in those older than 15 years. Lung imaging findings consistent with severe disease were significantly associated with an age of >15 years. Respiratory cultures were positive in 62% of the samples obtained. Half of the patients required hospitalization, while 45% showed extrapulmonary involvement. Evolution was as follows: 74% recovered from the illness, 13% were lost to follow-up, 11% were referred to a less complex facility, 1% experienced treatment failure, and 3 (1%) patients died. Pulmonary cavities and positive bacilloscopy were associated with the presence of pulmonary sequelae at the end of treatment. CONCLUSIONS: Tuberculosis in adolescents, particularly in those >15 years of age, may present characteristics similar to those of adults, with a higher frequency of severe pulmonary disease leading to pulmonary sequelae.

C1q modulation of antibody-dependent enhancement of dengue virus infection in human myeloid cell lines is dependent on cell type and antibody specificity.

Antibody-dependent enhancement (ADE) of dengue virus (DENV) infection is one of the mechanisms contributing to increased severity during heterotypic, secondary infection. The complement protein C1q has been shown to reduce the magnitude of ADE in vitro. Therefore, we investigated the mechanisms of C1q modulation of ADE, focusing on processes of viral entry. Using a model of ADE of DENV-1 infection in human myeloid cell lines in the presence of monoclonal antibodies, 4G2 and 2H2, we found that C1q produced nearly a 40-fold reduction of ADE of DENV-1 in K562 cells, but had no effect in U937 cells. In K562 cells, C1q reduced adsorption of DENV-1/4G2 and exerted a dual inhibitory effect on adsorption and internalization of DENV-1/2H2. Distinct endocytic pathways in the presence of antibody corresponded to conditions where C1q produced a differential action. Also, C1q did not affect the intrinsic cell response mediated by FcγR in human myeloid cells. The modulation of ADE of DENV-1 by C1q is dependent on the FcγR expressed on immune cells and the specificity of the antibody comprising the immune complex. Understanding protective and pathogenic mechanisms in the humoral response to DENV infections is crucial for the successful design of antivirals and vaccines.

2023 epidemic dengue fever outbreak: the experience of a pediatric hospital in the City of Buenos Aires. / Brote epidémico de dengue 2023: experiencia de un hospital pediátrico de la Ciudad de Buenos Aires.

Introduction. Dengue is a viral infection that may be asymptomatic or include severe manifestations. This study aims to describe the characteristics of a pediatric population during the epidemic outbreak in 2023. Population and methods. This cross-sectional study included patients with probable or confirmed dengue fever who were seen from March 13, 2023, to May 19, 2023, in a pediatric hospital in the Autonomous City of Buenos Aires. Results. A total of 112 patients were included. The median age was 12 years; 58% were male. Seventy-six percent of them came from the City of Buenos Aires. Twenty-five percent had cohabitants with symptoms compatible with a suspected case. The most frequent clinical manifestations were fever, headache, retro-ocular pain, myalgia, and arthralgia. The most frequent laboratory alterations were leukopenia (65%) and elevated transaminases (60%). Twenty-one percent (24/112) presented alarm signs and required hospitalization. Leukopenia, plateletopenia, and elevated transaminases were associated with the presence of alarm signs. RT-PCR was detected in fifty-three patients; serotype 2 was the most frequent. Twenty-one patients had positive NS1 tests, 18 patients had positive IgM, and 20 patients with clinical and epidemiological links were assumed to be probable dengue cases. There were no cases of severe dengue. Conclusion. Early clinical suspicion and recognition of laboratory parameters associated with alarm signs are essential for an adequate approach to the disease and early supportive treatment during dengue infection.

Introducción. El dengue es una infección viral que puede cursar de forma asintomática o incluir manifestaciones graves. El objetivo del trabajo es describir las características de una población pediátrica durante el brote epidémico del 2023. Población y métodos. Estudio de corte transversal que incluyó pacientes con dengue probable o confirmado atendidos del 13 de marzo de 2023 al 19 de mayo de 2023 en un hospital pediátrico de la Ciudad Autónoma de Buenos Aires. Resultados. Se incluyeron 112 pacientes. La mediana de edad fue 12 años; el 58 % fueron varones. El 76 % procedía de la Ciudad Autónoma de Buenos Aires. El 25 % tenía convivientes con sintomatología compatible con caso sospechoso. Las manifestaciones clínicas más frecuentes fueron fiebre, cefalea con dolor retroocular y mioartralgias. Las alteraciones de laboratorio más frecuentes fueron la leucopenia (65 %) y la elevación de transaminasas (60 %). El 21 % (24/112) presentó signos de alarma y requirió internación. La leucopenia, la plaquetopenia y el aumento de transaminasas se asociaron con la presencia de signos de alarma. Se confirmaron 53 pacientes por PCR-RT detectable, el serotipo 2 fue el más frecuente. Se asumieron como casos probables de dengue 21 pacientes con prueba NS1 positiva, 18 pacientes con IgM positiva y 20 pacientes con clínica y nexo epidemiológico. No hubo casos de dengue grave. Conclusión. Durante la infección por dengue, la sospecha clínica precoz y el reconocimiento de los parámetros de laboratorio asociados a los signos de alarma resultan esenciales para un adecuado abordaje de la enfermedad y un tratamiento de sostén precoz.

Antibody levels against respiratory syncytial virus fusion protein conformations and lack of association with life-threatening infection in previously healthy infants.

BACKGROUND: Humoral immune response against the pre-fusion (pre-F) conformation of respiratory syncytial virus (RSV) F protein has been proposed to play a protective role against infection. An RSV pre-F maternal vaccine has been recently approved in several countries to protect young infants against RSV. We aimed to assess serum IgG titers against the pre-F and post-F conformations of RSV F protein and their association with life-threatening RSV disease (LTD) in previously healthy infants. METHODS: A prospective cohort study including hospitalized infants <12 months with a first RSV infection was conducted during 2017-2019. Patients with LTD required intensive care and mechanical respiratory assistance. RSV pre-F exclusive and post-F antibody responses were determined by post-F competition and non-competition immunoassays, respectively, and neutralizing activity was measured by plaque reduction neutralization test. RESULTS: Fifty-eight patients were included; the median age was 3.5 months and 41 % were females. Fifteen patients developed LTD. RSV F-specific antibody titers positively correlated with neutralizing antibody titers in acute and convalescent phases but, importantly, they did not associate with LTD. Acute RSV pre-F exclusive and post-F IgG titers negatively correlated with patient age (P = 0.0007 and P < 0.0001), while a positive correlation was observed between the fold changes in RSV F-specific antibody titers between convalescent and acute phase and patient age (P = 0.0014 and P < 0.0001). Infants ≤2 months exhibited significantly lower fold-changes in RSV F-specific and neutralizing antibody titers between convalescence and acute phase than older infants. Additionally, acute RSV antibody titers showed no correlation with nasal RSV load and, furthermore, nasal viral load was not associated with the development of LTD. CONCLUSIONS: This study highlights that protection against life-threatening RSV disease is not necessarily antibody-dependent. Further characterization of the immune response against RSV and its role in protection against severe disease is important for the development of the safest possible preventive strategies.

Epidemiological and clinical features of the 2016-2018 Zika virus outbreak in northern Argentina.

BACKGROUND: During the American epidemic, Zika virus (ZIKV) expanded rapidly through dengue virus (DENV)-endemic regions. We analyzed the presentation of ZIKV infection in patients from the City of Orán, Argentina, and compared some of its features with dengue presentation in the same region. METHODS: A retrospective study was conducted at San Vicente de Paul Hospital during 2016-2018. Clinical and demographic characteristics, pre-existing immunity to DENV, viral load and type I interferon (IFN) responses were studied in 63 patients with ZIKV infection. RESULTS: Clinical manifestations of ZIKV infection were generally mild compared with dengue, although rash (p<0.001) and itching (p<0.001) were significantly more prevalent in ZIKV patients. ZIKV patients aged <15 y manifested relatively mild disease compared with older ZIKV patients, showing a decreased prevalence of headache (p=0.008), retro-orbital pain (p=0.001) and arthralgia (p=0.001). Increased Zika incidence was observed in female patients (60.3%). Serum viral load was low to undetectable in ZIKV patients and was not associated with serum anti-DENV IgG titers. Interferon-α and IFN-ß serum levels did not correlate with serum viral load in ZIKV patients. CONCLUSIONS: Clinical presentation of ZIKV and DENV infections is largely overlapping, presenting a challenge for diagnosis and risk assessment for uniquely at-risk populations.

Risks of low vaccination coverage and strategies to prevent the resurgence of vaccine-preventable diseases in infants in the COVID-19 pandemic scenario: recommendations for Latin America and the Caribbean by the group of experts on infant immunization for Latin America.

INTRODUCTION: The WHO 2030 Immunization Agenda (IA-2030) harmonizes immunization activity plans at community, national, regional and global levels. Additionally, medical societies play an important role. The Latin American Group of Experts on Infant Immunization, established in 2018, advises on the harmonization, update, and optimization of infant vaccination programs in Latin America and the Caribbean (LAC). In September 2021, 41 such experts from 13 LAC countries met to develop recommendations for increasing regional vaccination coverage to avoid the reemergence of vaccine-preventable diseases and/or the occurrence of outbreaks. AREAS COVERED: The following items were evaluated: (i) immunization challenges before and during the COVID-19 pandemic; (ii) the status of current immunization programs, particularly infant pertussis and polio vaccination; (iii) possible solutions for overcoming vaccination challenges and achieving regional vaccination coverage targets. EXPERT OPINION/COMMENTARY: Medical societies provide valuable recommendations to guide and update vaccination schedules. In the LAC region, possible strategies to achieve target vaccination rates include the use of combination vaccines, strengthening surveillance systems, improving school attendance, advancing vaccine education and confidence, striving for vaccination equity, widening operational capacity, creating strategic alliances, and strengthening the role of medical groups. It is hoped that these recommendations will be implemented in the LAC region.

Safety and pharmacokinetics of urtoxazumab, a humanized monoclonal antibody, against Shiga-like toxin 2 in healthy adults and in pediatric patients infected with Shiga-like toxin-producing Escherichia coli.

Shiga-like toxin-producing Escherichia coli (STEC) infection causes diarrhea, which is often bloody and which can result in potentially life-threatening hemolytic-uremic syndrome (HUS). Urtoxazumab, a humanized monoclonal antibody directed against the Shiga-like toxin 2 (Stx2) produced by STEC, has been developed as a promising agent for the prevention of HUS. Single randomized, intravenous, double-blind, placebo-controlled doses of urtoxazumab were administered to assess its safety and pharmacokinetics in healthy adults (0.1 to 3.0 mg/kg of body weight) and STEC-infected pediatric patients (1.0 and 3.0 mg/kg). No dose-related safety trends were noted, nor were antiurtoxazumab antibodies detected. The disposition of urtoxazumab showed a biexponential decline, regardless of the dose. In healthy adults, the mean terminal elimination half-life was consistent across the dose groups and ranged from 24.6 days (3.0-mg/kg dose group) to 28.9 days (0.3-mg/kg dose group). The mean maximum serum drug concentration (C(max)) ranged from 2.6 microg/ml at 0.1 mg/kg to 71.7 microg/ml at 3.0 mg/kg. The disposition of urtoxazumab following the administration of doses of 1.0 and 3.0 mg/kg in pediatric patients showed mean C(max)s of 19.6 and 56.1 microg/ml, respectively. Urtoxazumab was well tolerated, appears to be safe at doses of up to 3.0 mg/kg, and is a potential candidate for the prevention of HUS in pediatric patients.

First case of human infection due to Pseudomonas fulva, an environmental bacterium isolated from cerebrospinal fluid.

We report the first case of human infection due to Pseudomonas fulva. P. fulva caused acute meningitis following the placement of a drainage system in a 2-year-old female. Additionally, the isolate displayed a VIM-2 carbapenemase in a class 1 integron context.

[Exogenous Cushing syndrome due to drug interaction of ritonavir and inhaled fluticasone. Report of three pediatric cases]. / Síndrome de Cushing exógeno por interacción medicamentosa de ritonavir y fluticasona inhalada. Reporte de tres casos pediátricos.

The increase in life expectancy with the advent of highly effective antiretroviral therapy poses challenges in terms of toxicity and drug interactions. Exogenous Cushing syndrome by interaction between ritonavir and inhaled fluticasone in children diagnosed with human immunodeficiency virus infection and chronic pulmonary pathology is rare. So far, there are 20 cases reported. Three pediatric cases are reported, with a diagnosis of human immunodeficiency virus infection and chronic pulmonary pathology who presented exogenous Cushing syndrome with inhaled fluticasone at usual doses due to drug interaction between it and ritonavir. The patients resolved the clinical picture after 2-4 months of fluticasone suspension and remain asymptomatic in the follow-up.

El incremento de la expectativa de vida con el advenimiento de la terapia antirretroviral de alta eficacia plantea desafíos en cuanto a la toxicidad e interacciones medicamentosas. El síndrome de Cushing exógeno por interacción entre ritonavir y fluticasona inhalada en niños con diagnóstico de infección por virus de la inmunodeficiencia humana y patología pulmonar crónica es infrecuente. Hasta el momento, hay 20 casos reportados. Se describen 3 casos pediátricos con diagnóstico de infección por virus de la inmunodeficiencia humana y patología pulmonar crónica que presentaron síndrome de Cushing exógeno con fluticasona inhalada en dosis habituales por la interacción medicamentosa entre esta y ritonavir. Los pacientes resolvieron el cuadro clínico luego de 2-4 meses de suspensión de la fluticasona y permanecieron asintomáticos en el seguimiento.

Clinical and epidemiological impact of respiratory syncytial virus and identification of risk factors for severe disease in children hospitalized due to acute respiratory tract infection. / Impacto clínico-epidemiológico del virus sincicial respiratorio e identificación de factores de riesgo de enfermedad grave en niños hospitalizados por infección respiratoria aguda.

INTRODUCTION: Severe acute respiratory tract infection (ARTI) is a very common cause of hospitalization in pediatrics; respiratory syncytial virus (RSV) is the major etiologic agent. Accurately defining the burden of RSV life-threatening disease (LTD) and its risk factors is a challenge. OBJECTIVES: To know the impact of RSV in children hospitalized due to ARTI and describe the risk factors for LTD. MATERIALS AND METHODS: Prospective study in children < 2 years old hospitalized due to ARTI during 2012-2013 at Hospital de Niños "R. Gutiérrez." LTD was defined as requiring non-invasive ventilation and/or mechanical ventilation. RESULTS: 622 studied children, 372 were RSV(+) (59.8 %). Annual rate of hospitalization due to RSV in infants < 1 year old: 956 (95 % CI: 858-1062)/10 000hospitalizations. RSV caused 56/78 (71.8 %) cases of LTD; 42 (75 %) were previously healthy subjects; 32 (76.2 %) were < 6 months old. In the multivariate analysis, RSV was a risk factor for LTD (adjusted odds ratio [aOR]: 2.04; 95 % CI: 1.15-3.63; p = 0.014). A differential effect by sex was identified in RSV(+) patients: over-crowding was a risk factor for LTD in males (aOR: 2.36; 95 % CI: 1.07-5.21; p = 0.033); breastfeeding was a significant protective factor in females (aOR: 0.342; 95 % CI: 0.13-0.91; p = 0.032). CONCLUSIONS: RSV caused more than half of ARTI cases and mostly affected previously healthy patients < 1 year old. Males living in overcrowding conditions and females who were not breastfed were at the greatest risk for LTD.

Introducción: La infección respiratoria aguda grave (IRA) es una causa muy frecuente de internación en pediatría; el virus sincicial respiratorio (VSR) es el principal agente etnológico. Definir en forma precisa la carga de enfermedad que compromete la vida (ECV) por este virus y los factores de riesgo es un desafío. Objetivos: Conocer el impacto del VSR en internados por IRA y describir factores de riesgo de ECV. Materiales y métodos: Estudio prospectivo en niños < 2 años internados por IRA durante 20122013 en el Hospital de Niños "R. Gutiérrez". Se definió ECV el requerimiento de ventilación no invasiva y/o asistencia respiratoria mecánica. Resultados: 622 niños estudiados, 372 VSR (+) (el 59,8 %). Tasa de hospitalización anual por VSR en < 1 año: 956 (IC 95 %: 858-1062)/10 000 internaciones. El VSR causó 56/78 (el 71,8 %) casos de ECV; 42 (el 75 %) eran previamente sanos; 32 (el 76,2 %) tenían < 6 meses de edad. En el análisis multivariado, el VSR fue un factor de riesgo de ECV (odds ratio ajustado [ORa] 2,04; IC 95 %: 1,15-3,63; p = 0,014). Se identificó un efecto diferencial según género en pacientes VSR (+): el hacinamiento fue un factor de riesgo de ECV en varones (ORa 2,36; IC 95 %: 1,07-5,21; p = 0,033); la lactancia materna protegió significativamente a las niñas (ORa 0,342; IC 95 %: 0,13-0,91; p = 0,032). Conclusiones: El VSR causó más de la mitad de los casos de IRA y afectó, en su mayoría, a pacientes < 1 año previamente sanos. Los varones en condiciones de hacinamiento y las niñas que no recibieron leche materna constituyeron el grupo con mayor riesgo de ECV.

[Dengue outbreak in Buenos Aires, Argentina, 2016: Clinical and hematological features in children]. / Brote epidémico de dengue en la Ciudad de Buenos Aires, 2016: características clínicas y hematológicas de la infección en una población pediátrica.

Dengue is the human arbovirus with the highest morbidity and mortality in the world. The largest outbreak of dengue in Buenos Aires, Argentina, occurred during 2016. OBJECTIVE: To describe clinical and hematological features in children with confirmed dengue infection. METHODS: Cross sectional study that included children attended since January 18th to April 15th 2016 at Hospital de Niños "Dr. Ricardo Gutiérrez". RESULTS: among 156 registered cases, 82 confirmed cases by virology test; 130 (83 %) autochthonous cases. The most frequent clinical manifestations were fever, headache and retro-ocular pain. Laboratory abnormalities were leukopenia, thrombocytopenia and increased liver enzymes. Thirty-five children were hospitalized (23 %), 25 (16 %) with warning signs. In our study, no cases of severe dengue occurred. CONCLUSIONS: early recognition of warning signs and hematological monitoring is essential in order to detect patients at risk and offer them adequate early treatment.

El dengue es la arbovirosis humana que más morbimortalidad ocasiona mundialmente. Durante 2016, se registró, en la Ciudad de Buenos Aires, Argentina, la mayor epidemia de esta enfermedad. Objetivo: describir las características clínicas y hematológicas en una población pediátrica. Métodos: estudio de corte transversal que incluyó a pacientes atendidos del 18-1-16 al 15-4-16 en el Hospital de Niños "Dr. Ricardo Gutiérrez". Resultados: se registraron 156 casos, 82 confirmados por virología; 130 (83 %), autóctonos. Las manifestaciones clínicas más frecuentes fueron fiebre, cefalea y dolor retroocular. Las alteraciones del laboratorio significativas fueron leucopenia, plaquetopenia y aumento de transaminasas. Se internaron 35 pacientes (23 %), 25 (16 %) con signos de alarma. No se presentó ningún caso de dengue grave. Conclusiones: el reconocimiento oportuno de los signos de alarma y el control hematológico resultan fundamentales para detectar a los niños en riesgo y ofrecerles tratamiento de soporte en forma precoz.

Remarks on the possibility of introducing the fractionated dose of the inactivated poliomyelitis vaccine in the Latin American Child Immunization Schedule.

Given that the last notified case of poliomyelitis due to wild poliovirus type 2 was in 1999, in 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) recommended the withdrawal of the type 2 component of oral polio vaccine (OPV) and the introduction of a bivalent OPV (bOPV) in all countries by 2016. WHO recommended also that the withdrawal should be preceded by the introduction of at least one dose of inactivated poliovirus vaccine (IPV) in routine immunization schedules. The introduction of IPV prior to the change of the bOPV in 2016 to trivalent OPV (tOPV) was based on the concept of ensuring that a substantial proportion of the population would be protected against type 2 polio after the removal of the type 2 OPV. However, the world's two producers of IPV (Bilthoven Biologicals and Sanofi) have faced problems in the production of this vaccine and therefore reported a reduction of the global supply of IPV. In response to the potential shortage of IPV, at a meeting held on March 10 2017, the SAGE and Technical Advisory Group (TAG) of the Pan American Health Organization (PAHO) urged the countries in the Latin American region to replace the routine administration of the full doses of inactivated polio vaccine (IPV-C) in the immunization schedule (administered by intramuscular route), administering a fraction of the full dose in two intradermal shots (IPV-f). The possibility of this strategy was analyzed by opinion leaders convened by the Paraguayan Society of Pediatrics with the support of the Latin American Society of Pediatric Infectious Diseases (SLIPE) and Latin American Association of Pediatrics (ALAPE). This document presents the results of the discussion.

[Pediatric pyomyositis: Experience in a Pediatric Reference Center in Argentina]. / Piomiositis en niños: experiencia en un hospital pediátrico de referencia en Argentina.

BACKGROUND: Pyomyositis is the infection of skeletal muscle, a rare pathology in children. Aim To describe the characteristics of pyomyositis in pediatric patients. METHODS: Prospective analytical study of hospitalized children diagnosed with pyomyositis from May 2016 to April 2017 at the Ricardo Gutiérrez Children's Hospital, Buenos Aires, Argentina. RESULTS: Twenty-one patients with pyomyositis were identified. Annual rate: 21.5/10,000 admissions (95% CI 4.65-71.43). The median age was 5.4 years (range 1.25-11.6). The lower limbs were the most affected site. C-reactive protein (CRP) was elevated in all patients, with a mean of 124 mg/L (SD 96), being significantly higher in patients with bacteremia: 206 (DS 101) vs 98 (DS 81), p = 0.02. Bacterial cultures were positive in 17/21 (80.9%): 15 methicillin-resistant Staphylococcus aureus (MRSA), and 2 Streptococcus pyogenes. Blood cultures were positive in 5 (23.8%). CONCLUSION: MRSA-community acquired is the predominant pathogen in our setting. In the selection of the appropriate empirical treatment, the local resistance pattern and the CRP value should be taken into account.

Clinical and epidemiological impact of varicella infection in children prior to the introduction of the varicella vaccine in the national immunization schedule of Argentina. / Impacto clínico y epidemiológico de las infecciones por varicela en niños previo a la introducción de la vacuna al Calendario Nacional de Argentina.

INTRODUCTION: In Argentina, an estimated 400 000 varicella cases occur annually. Given the under-recording of existing cases, the actual burden of disease is unknown. OBJECTIVE: To assess the burden of varicella before the introduction of the varicella vaccine in the national immunization schedule. MATERIALS AND METHODS: Retrospective, analytical, observational study carried out in three hospitals of Argentina. Review of medical records from outpatient visits to the Emergency Department and from patients younger than 18 years hospitalized for varicella. Period: 1/2011-12/2013. RESULTS: A total of 382 782 outpatients were seen; 3367(0.88%) corresponded to visits due to varicella; 57.6 % were < 4 years old. A total of 164 (4.9 %) patients required hospitalization, with an overall hospitalization rate of 65.3/10 000 hospitalized patients/year (95 % confidence interval |#91;CI|#93;: 55.4-76.5); hospitalization rate in healthy children: 57.2/10 000 (95 % CI: 67.7-48.0); median age: 31.5 months. The most common causes of hospitalization were skin and/or soft tissue infections (61.1 %) and respiratory infections (10.1 %). Also, 54.3 % were treated with acyclovir and 73.1 %, with antibiotics. Bacteremia developed in 5/67 patients (7.5 %), all cases were caused by Gram-positive cocci and occurred in immunocompetent patients. Out of 19 immunocompromised patients, 36.8 % had complications (5 skin and/or soft tissue infection and 2 pneumonia cases). The median length of stay was 4 days, which is significantly more prolonged in immunocompromised patients. One patient required intensive care. No patient died. CONCLUSION: The burden of disease was significant, with a considerable impact in patients without an underlying disease.

Introducción. En Argentina, se estiman 400 000 casos anuales de varicela. Dado el subregistro de casos existentes, la carga de enfermedad real se desconoce. Objetivo. Evaluar la carga de enfermedad por varicela antes de la introducción de la vacuna al Calendario Nacional. Materiales y métodos. Estudio retrospectivo, analítico, observacional, realizado en tres centros asistenciales del país. Revisión de los registros de consultas ambulatorias a los Servicios de Urgencias y de las historias clínicas de las internaciones por varicela en pacientes < 18 años. Período: 1/2011-12/2013. Resultados. Fueron asistidas un total de 382782 consultas ambulatorias; 3367 (0,88 %) correspondieron a consultas por varicela; el 57,6 %, < 4 años. Requirieron internación 164 (4,9 %) con una tasa de hospitalización global de 65,3/10000 hospitalizados/año (IC 95 %: 55,4-76,5); tasa de hospitalización en niños sanos: 57,2/10 000 (IC 95 %: 67,7-48,0); mediana de edad: 31,5 meses. Las causas de internación más frecuentes fueron infecciones de piel y/o partes blandas (61,1 %) y respiratorias (10,1 %). El 54,3 % recibió tratamiento con aciclovir, y el 73,1 %, con antibióticos. Presentaron bacteriemia 5/67 (7,5 %), todas por cocos Gram(+) y en inmunocompetentes. De los 19 pacientes inmunocomprometidos, el 36,8 % tuvo complicaciones (5 infecciones de piel y/o partes blandas y 2 neumonías). La mediana de días de internación fue 4, significativamente más prolongada en pacientes inmunocomprometidos. Un paciente requirió cuidados intensivos. No hubo fallecidos. Conclusión. La carga de enfermedad registrada fue significativa, con impacto considerable en pacientes sin patología de base.

[Remarks on the possibility of the introduction of fractionated dose of the inactivated poliomyelitis vaccine in the Latin American Child Immunization Schedule]. / Consideraciones referente a la posibilidad de introducir la dosis fraccionada de la vacuna antipoliomielitis inactivada en el calendario de Inmunizaciones del Niño Latinoamericano.

As last notified case of poliomyelitis due to wild poliovirus type 2 was 1999, in 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) recommended the withdrawal of the type 2 component of oral polio vaccine (OPV) and the introduction of bivalent OPV (bOPV) in all countries by 2016. WHO recommended also that the withdrawal should be preceded by the introduction of at least one dose of inactivated poliovirus vaccine (IPV) in routine immunization schedules. The introduction of IPV prior to the change of the bOPV in 2016 to trivalent OPV (tOPV) was based on the concept of ensuring that a substantial proportion of the population would be protected against type 2 polio after the removal of the type 2 OPV. However, the world's two producers of IPV (Bilthoven Biologicals and Sanofi) have faced problems in the production of this vaccine and therefore reported reduction in IPV global supply. In response to the possible shortage of IPV, the SAGE and Technical Adviser Group (TAG) of the Pan American Health Organization (PAHO), in the meeting of March 10, 2017, has urged that countries in the Latinamerican region should replace the routine administration of the full doses of polio inactivated vaccine (IPV-C) in the immunization schedule (administered by intramuscular route) by the administration of a fraction of the full dose in two shots by intradermal route (IPV-f). The possibility of this strategy was analyzed by leaders of opinions gathered by the call of the Paraguayan Pediatric Society with the support of the Latin American Society of Pediatric Infectious Diseases (SLIPE) and Latin American Association of Pediatrics (ALAPE). The results of the discussion are presented in this document.

Rapid Decrease in Rates of Hospitalization Resulting From Invasive Pneumococcal Disease and Community-Acquired Pneumonia in Children Aged <60 Months After 13-Valent Pneumococcal Conjugate Vaccine Introduction in Argentina.

BACKGROUND: In January 2012, Argentina included universal pneumococcal vaccination in the routine childhood vaccination program using a 13-valent pneumococcal conjugate vaccine (PCV13). A 2 + 1 schedule (2 doses in the first year of life and a booster dose at 12 months of age) in children aged <2 years and 2-dose catch-up immunization in children aged 13 to 24 months was administered during the first year of vaccine introduction. The purpose of this study was to assess the burdens of invasive pneumococcal disease (IPD) and/or community-acquired pneumonia (CAP) in hospitalized children younger than 5 years during the first 2 years of the program compared to those in the prevaccination period in our setting. METHODS: This was a multicenter, prospective, and descriptive study. Rates of hospitalization resulting from IPD and/or CAP in 5 pediatric reference centers across the country were analyzed (every 10 000 admissions). Clinical, epidemiologic, and microbiological data were recorded. Statistical analysis using Stata 8.0 was performed. RESULTS: A comparison of rates of hospitalization resulting from global IPD and/or CAP in the prevaccine (2009-2011) and postvaccine (2012-2013) periods revealed significant decreases of 50% (P = .003) and 51% (P < .0001), respectively. Significant decreases were also observed in number of hospitalizations resulting from empyema (39%; P = .03) and pneumococcal empyema (67.8%; P = .007); the reduction was not statistically significant for pneumococcal CAP (58%; P = .18). Hospital stays for IPD and/or CAP decreased by 56%. CONCLUSION: Rapid and significant decreases in the rates of hospitalization resulting from IPD and/or CAP during the first 2 years after PCV13 introduction were observed. A longer surveillance period is required to confirm these results and the effectiveness of the vaccination program.