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.

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.

Distinct Immune Phenotypes and Cytokine Profiles in Children with Differing Severity of COVID-19.

Background: Coronavirus disease 2019 (COVID-19) is usually mild and self-limited in children. However, a few Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infections in children may progress to severe disease with respiratory distress or can result in a multisystem inflammatory syndrome (MIS-C) associated with COVID-19. The immune mechanisms for these differential clinical outcomes are largely unknown.

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.

Genetic Susceptibility to Life-threatening Respiratory Syncytial Virus Infection in Previously Healthy Infants.

Background: Genetic background may be an important host determinant of respiratory syncytial virus (RSV) disease severity, but full characterization of susceptibility genes remains unclear. This study aimed to assess the presence of specific single-nucleotide polymorphisms (SNPs) in selected genes codifying for different components of the antiviral innate immune response, to determine their role for developing RSV life-threatening disease (LTD).

Methods: Prospective cohort study including previously healthy full-term infants hospitalized with a first RSV infection during 2017-2018.

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.

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.

[Dengue outbreak in Buenos Aires, Argentina, 2016: Clinical and hematological features in children].

Unlabelled: 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.

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.

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.

Modeling the long-term persistence of hepatitis A antibody after a two-dose vaccination schedule in Argentinean children.

Background: Long-term seroprotection data are essential for decision-making on the need and timing of vaccine boosters. Based on data from longitudinal serological studies, modeling can provide estimates on long-term antibody persistence and inform such decision-making.

Methods: We examined long-term anti-hepatitis A virus (anti-HAV) antibody persistence in Argentinean children ≤15 years after the initial study where they completed a 2-dose course of inactivated hepatitis A vaccine (Avaxim 80U Pediatric, Sanofi Pasteur, Lyon, France).

Pandemic influenza A/H1N1 2009 antibodies in the metropolitan area of Buenos Aires in Argentina.

Objective: To estimate the infection prevalence in Buenos Aires during the outbreak of pandemic influenza A/H1N1 2009 virus (A(H1N1)pdm09).

Methods: A(H1N1)pdm09-specific antibodies were measured by hemagglutination inhibition assay in human serum samples collected 6 months after the outbreak and before the introduction of the A(H1N1)pdm09 vaccine in Argentina. Baseline levels of cross-reactive antibodies to A(H1N1)pdm09 were determined by testing 162 serum samples collected before 2009.

Case characteristics and use of oseltamivir in children and household contacts.

In May 2009, the onset of pandemic influenza A (H1N1) began in Buenos Aires schools and a containment program was implemented. We report the first 191 school-aged cases. Influenza (H1N1) was a mild disease in children.

An epidemiologic surveillance of Shiga-like toxin-producing Escherichia coli infection in Argentinean children: risk factors and serum Shiga-like toxin 2 values.

Background And Aims: Shiga-like toxin (Stx)-producing Escherichia coli (STEC) infection is an ongoing health issue that can lead to serious complications, including hemolytic uremic syndrome (HUS) and death. This study assessed demographic and epidemiologic information of STEC infection among Argentinean children.

Methods: A prospective surveillance of 2435 screened children (age, 0.

Long-term immunity after two doses of inactivated hepatitis A vaccine, in Argentinean children.

We examined long-term anti-hepatitis A virus antibody persistence in Argentinean children 10 years after the initial study in which they received 2 doses of inactivated hepatitis A vaccine (Avaxim 80U). Of the 111 children, 48 from the initial trial were enrolled. Of 48, 47 (97.

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.

Hepatitis A vaccination of Argentinean infants: comparison of two vaccination schedules.

Background: Early immunization to protect infants against hepatitis A (HA) is recommended in intermediate or high endemic areas of the world, but little is known of the effects of maternal antibodies on the immune response. We studied the immunogenicity and reactogenicity of an inactivated HA vaccine administered in two different schedules to 2-month-old infants in an intermediate/high endemic area in Argentina.

Methods: In this double-blind, randomized study 131 infants received either three doses (at 2, 4, 6 months of age [Group A]) or one dose (at 6 months of age [Group B]) of the pediatric inactivated HA vaccine, Avaxim 80, and a booster dose at 15-18 months.

Safety and immunogenicity of a pediatric formulation of inactivated hepatitis A vaccine in Argentinean children.

Background: Children are a reservoir of hepatitis A virus and must be considered as primary targets of any immunization strategy. The safety and immunogenicity were evaluated for a new formulation of an inactivated hepatitis A vaccine, Avaxim 80 units, containing one-half the antigen dose of the adult formulation.

Methods: The safety of two doses of this vaccine given 6 months apart was evaluated in an open study in 537 Argentinean children 12 months to 15 years old.

Shigella and Shiga toxin-producing Escherichia coli causing bloody diarrhea in Latin America.

In Latin America, Shigella and shiga toxin-producing Escherichia coli are the two leading agents in the cause of bloody diarrhea. The already high and increasing antimicrobial resistance of Shigella also is a significant problem. Shiga toxin-producing E.

Perspectives on Shiga-like Toxin Infections in Argentina .

Argentina has the highest frequency of hemolytic uremic syndrome (HUS) in the world (300 cases/year). The risk of HUS in children from 6 to 48 months old is approximately 22/100,000 in Buenos Aires. In Argentina, HUS is the most frequent cause of acute renal damage and the second cause of chronic renal injury in children.

Incomplete hemolytic-uremic syndrome in Argentinean children with bloody diarrhea.

Argentina has an exceptionally high frequency of hemolytic-uremic syndrome (HUS). We sought to define prospectively the role of verocytotoxins (Shiga-like toxins [SLTs]) in 254 Argentinean children with grossly bloody diarrhea during spring and summer. Free fecal SLTs (I/II) and/or DNA probe-positive isolates were found in 99 (39%) of the children.

Tumor necrosis factor concentrations in hemolytic uremic syndrome patients and children with bloody diarrhea in Argentina.

Hemolytic uremic syndrome (HUS) is thought to be a vascular endothelial injury disease. The mechanism of injury is unknown although verocytotoxins (Shiga-like toxins (SLTs)) are known to be associated with it. Recent evidence suggests that in vitro treatment of some endothelial cells with tumor necrosis factor alpha (TNF-alpha) dramatically increases their susceptibility to SLTs.

Ceftibuten and trimethoprim-sulfamethoxazole for treatment of Shigella and enteroinvasive Escherichia coli disease.

In a prospective randomized study at two clinical sites, ceftibuten was compared with trimethoprim-sulfamethoxazole (TMP-SMX), both given orally for a period of 5 days, for the treatment of dysentery. Twenty-two children were found to have bacillary dysentery caused by Shigella and/or enteroinvasive Escherichia coli. All organisms isolated were susceptible to ceftibuten; 6 of 20 Shigella strains and 4 of 5 enteroinvasive E.