Publications by authors named "Mathie Lorrot"

Article Synopsis
  • * Researchers analyzed data from 361 infants with confirmed pertussis, finding that 32 (9%) developed fulminant symptoms, which were more common in neonates, unvaccinated, and premature infants.
  • * Results indicated that B. pertussis strains that produced PRN were associated with higher risks of fulminant pertussis, suggesting the significance of PRN in the severity of the disease.
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  • The human immune system continues to develop for several years after birth, affecting how young children respond to infections, such as SARS-CoV-2.
  • Researchers studied T cell responses in children and adults before, during, and after SARS-CoV-2 infection, revealing that younger children (under 5) had a weaker CD4 T cell response compared to older children and adults with mild disease.
  • Following infection, preschool-age children produced similar neutralizing antibodies to adults but had different T cell characteristics and fewer memory B cells, indicating a gradual maturation of their adaptive immune responses.
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  • Respiratory syncytial virus (RSV) causes bronchiolitis in infants, and the monoclonal antibody nirsevimab was approved in the EU in 2022, leading to a national immunisation campaign in France starting September 2023.
  • A study was conducted in Paris to evaluate nirsevimab's effectiveness in reducing emergency department visits and hospitalisations for bronchiolitis among infants aged 12 months or younger during the RSV season of 2023-24.
  • Out of 2786 infants studied, those who received nirsevimab showed lower rates of emergency visits and hospitalisation for bronchiolitis compared to non-vaccinated infants, but data showed that the majority of those
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  • RSV is a major cause of bronchiolitis, leading to 3 million hospitalizations each year, and nirsevimab is a monoclonal antibody aimed at preventing severe RSV cases in infants.
  • A study compared infants hospitalized for RSV bronchiolitis with those visiting for unrelated reasons, assessing nirsevimab’s effectiveness in preventing hospitalizations in those under 12 months old.
  • Findings showed nirsevimab reduced hospitalization rates for RSV-associated bronchiolitis by 83% and critical care needs by about 70%, indicating it is an effective treatment option for vulnerable infants.
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Resistance of Gram-negative bacteria to the most widely used antibiotics, particularly β-lactams, is now considered as major public health problem. The main resistance mechanisms to β-lactams in Enterobacterales are the production of extended spectrum β-lactamases (ESBL) or carbapenemases, which hydrolyze virtually all β-lactams. However, a substantial proportion of carbapenem-resistant Gram-negative bacilli do not produce carbapenemase but combine overproduction of a cephalosporinase and/or ESBL with very low penem hydrolysis and reduced outer membrane permeability.

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Most osteoarticular infections (OAI) occur via the hematogenous route, affect children under 5 years of age old, and include osteomyelitis, septic arthritis, osteoarthritis and spondylodiscitis. Early diagnosis and prompt treatment are needed to avoid complications. Children with suspected OAI should be hospitalized at the start of therapy.

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Bacterial skin infections are common in children, and frequently do not require systemic antibiotic therapy, particularly for superficial forms. In these cases, washing (with soap and water) and careful rinsing of the lesion are the key points of treatment. A semiotic analysis must precede any therapeutic decision to assess the appropriateness of antibiotic therapy, need for drainage (which may be spontaneous or surgical) and possible existence of symptoms related to toxin production, which are frequent signs of severity.

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RSV is an almost obligatory virus responsible for upper (rhinitis and otitis) and lower (bronchiolitis and asthma attack) respiratory infections in children under 5 years of age. Reinfections are frequent at all ages because immunity is only partial and does not last long. Young children under the age of 1 are the most affected.

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Objectives: Acute bronchiolitis is a major public health issue with high number of infants hospitalised worldwide each year. In France, hospitalisations mostly occur between October and March and peak in December. A reduction of emergency visits for bronchiolitis has been observed at onset of the COVID-19 outbreak.

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Aim: We aimed to investigate the performance of procalcitonin (PCT) assay between 12 and 36 h after onset of fever (PCT H12-H36) to predict invasive bacterial infection (IBI) (ie, meningitis and/or bacteremia) in febrile neonates.

Methods: We retrospectively included all febrile neonates hospitalized in the general pediatric department in a teaching hospital from January 2013 to December 2019. PCT assay ≤ 0.

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SARS-CoV-2 diagnosis is a cornerstone for the management of coronavirus disease 2019 (COVID-19). Numerous studies have assessed saliva performance over nasopharyngeal sampling (NPS), but data in young children are still rare. We explored saliva performance for SARS-CoV-2 detection by RT-PCR according to the time interval from initial symptoms or patient serological status.

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Article Synopsis
  • Non-pharmaceutical interventions (NPIs) against COVID-19, implemented in March 2020, resulted in a significant reduction in hospitalized community-acquired pneumonia (hCAP) cases in children in France.
  • A detailed analysis of 2,972 hCAP cases revealed a 63% drop in monthly cases after NPIs began, with a notable increase in the median age of affected children.
  • The study also found that fewer children had high inflammatory markers and there was a trend towards a decrease in pleural effusion cases during the NPI period, suggesting changes in the pathogens causing hCAP.
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Multisystem inflammatory syndrome in children (MIS-C) is the most severe form associated with SARS-CoV-2 infection in children. To reduce the spread of SARS-CoV-2 at the population level, educational setting closure have been implemented in many countries. However, the direct benefit of school closure on the MIS-C burden remains to be explored.

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Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children is generally milder than in adults, but a proportion of cases result in hyperinflammatory conditions often including myocarditis.

Methods: To better understand these cases, we applied a multiparametric approach to the study of blood cells of 56 children hospitalized with suspicion of SARS-CoV-2 infection. Plasma cytokine and chemokine levels and blood cellular composition were measured, alongside gene expression at the bulk and single-cell levels.

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BackgroundChildren have a low rate of COVID-19 and secondary severe multisystem inflammatory syndrome (MIS) but present a high prevalence of symptomatic seasonal coronavirus infections.AimWe tested if prior infections by seasonal coronaviruses (HCoV) NL63, HKU1, 229E or OC43 as assessed by serology, provide cross-protective immunity against SARS-CoV-2 infection.MethodsWe set a cross-sectional observational multicentric study in pauci- or asymptomatic children hospitalised in Paris during the first wave for reasons other than COVID (hospitalised children (HOS), n = 739) plus children presenting with MIS (n = 36).

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Background: The extent to which very young children contribute to the transmission of SARS-CoV-2 is unclear. We aimed to estimate the seroprevalence of antibodies against SARS-CoV-2 in daycare centres that remained open for key workers' children during a nationwide lockdown in France.

Methods: Children and staff who attended one of 22 daycare centres during a nationwide lockdown in France (between March 15 and May 9, 2020) were included in this cross-sectional, multicentre, seroprevalence study.

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Article Synopsis
  • Acute arthritis is a frequent issue in pediatric emergencies, often attributed to juvenile idiopathic arthritis (JIA), septic arthritis (SA) caused by bacteria like Kingella kingae, or undetermined causes (UA).
  • A study compared young patients under 6 years old with diagnoses of JIA, SA, or UA in terms of clinical characteristics, hospital stays, use of intravenous antibiotics, and surgical interventions after joint aspiration.
  • Findings indicated that patients with JIA were older and had lower white blood cell counts in serum and synovial fluid compared to those with SA, emphasizing the importance of accurate diagnosis for treatment.
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Importance: Multisystem inflammatory syndrome in children (MIS-C) is the most severe pediatric disease associated with severe acute respiratory syndrome coronavirus 2 infection, potentially life-threatening, but the optimal therapeutic strategy remains unknown.

Objective: To compare intravenous immunoglobulins (IVIG) plus methylprednisolone vs IVIG alone as initial therapy in MIS-C.

Design, Setting, And Participants: Retrospective cohort study drawn from a national surveillance system with propensity score-matched analysis.

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Background: Initial reports on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in children suggested that very young age and comorbidities may increase risk of severe evolution, but these findings remained to be confirmed. We aimed to analyze the clinical spectrum of hospitalized pediatric SARS-CoV-2 infection and predictors of severe disease evolution.

Methods: We conducted a French national prospective surveillance of children hospitalized with SARS-CoV-2 infection.

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Aim: This study determined the influence of the COVID-19 pandemic on the occurrence of multisystem inflammatory syndrome in children (MIS-C) and compared the main characteristics of MIS-C and Kawasaki disease (KD).

Methods: We included patients aged up to 18 years of age who were diagnosed with MIS-C or KD in a paediatric university hospital in Paris from 1 January 2018 to 15 July 2020. Clinical, laboratory and imaging characteristics were compared, and new French COVID-19 cases were correlated with MIS-C cases in our hospital.

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Introduction: While drug prescription should be based on established recommendations stemming from clinical trials but in pediatrics, many drugs are used without marketing authorization. Consequently recommendations are often based on clinical experience and the risk of inappropriate prescription (IP) is high. A tool for detecting IP in pediatrics-called POPI (Pediatrics: Omission of Prescriptions and Inappropriate prescriptions)-has been developed in France.

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This case series examines cardiac MRI findings in four children and adolescents admitted to intensive care in April 2020 for multisystem inflammatory syndrome and Kawasaki disease-like features related to coronavirus disease 2019 (COVID-19). Acute myocarditis occurred less than 1 week after onset of fever and gastrointestinal symptoms. Physical examination showed rash and cheilitis or conjunctivitis.

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Nitrous oxide (NO) is widely used as an anesthetic or an analgesic. NO prolonged and recurrent administration is known to affect vitamin B12 metabolism with subsequent clinical consequences. We report herein the case of a 13-year-old girl with sickle cell disease exhibiting severe neurological and biochemical signs of functional vitamin B12 deficiency due to prolonged and repeated exposure to NO.

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