Clinical characteristics of paediatric H1N1 admissions in Birmingham, UK

Bibliometric analysis of publication trends and topics of influenza-related encephalopathy from 2000 to 2022

BACKGROUND

Influenza-related encephalopathy is a rapidly progressive encephalopathy that usually presents during the early phase of influenza infection and primarily manifests as central nervous system dysfunction. This study aimed to analyze the current research status and hotspots of influenza-related encephalopathy since 2000 through bibliometrics analysis.

METHODS

The Web of Science Core Collection (WOSCC) was used to extract global papers on influenza-related encephalopathy from 2000 to 2022. Meanwhile, the VOSviewer and CiteSpace software were used for data processing and result visualization.

RESULTS

A total of 561 published articles were included in the study. Japan was the country that published the most articles, with 205 articles, followed by the United States and China. Okayama University and Tokyo Medical University published the most articles, followed by Nagoya University, Tokyo University, and Juntendo University. Based on the analysis of keywords, four clusters with different research directions were identified: "Prevalence of H1N1 virus and the occurrence of neurological complications in different age groups," "mechanism of brain and central nervous system response after influenza virus infection," "various acute encephalopathy" and "diagnostic indicators of influenza-related encephalopathy."

CONCLUSIONS

The research progress, hotspots, and frontiers on influenza-related encephalopathy after 2000 were described through the visualization of bibliometrics. The findings will lay the groundwork for future studies and provide a reference for influenza-related encephalopathy. Research on influenza-related encephalopathy is basically at a stable stage, and the number of research results is related to outbreaks of the influenza virus.

Trends in Influenza and Related Health Resource Use During 2005-2021 Among Children in Japan

BACKGROUND

To determine the epidemiological trends in pediatric influenza and changes in healthcare resource use from 2005 to 2021 using nationally representative outpatient database in Japan.

METHODS

We conducted a retrospective cohort study consisting of 3.5 million children with 177 million person-months during 2005-2021 using Japan Medical Data Center claims database in Japan. We investigated trends in incidence rates of influenza and changes in healthcare resource use (eg, use of antivirals) over 17 years. Generalized estimation equations were used to investigate the impact of the 2009 influenza pandemic and the coronaviral disease 2019 (COVID-19) pandemic on incidence rates of influenza and related healthcare utilization.

RESULTS

Annual incidence rates of influenza were estimated at 55 cases per 1000 person-years with a 93% relative increase [95% confidence interval (CI): 80%-107%] during the 2009 influenza pandemic and a 99.4% relative reduction (95% CI: 99.3%-99.4%) during the COVID-19 pandemic. Similar patterns were observed for health resource use, total healthcare costs, admission rates and antiviral agent use. Approximately 80% of children with influenza received prescriptions for antivirals. The most prescribed antivirals were oseltamivir, but we observed a temporal increase in zanamivir use during 2007-2009, an increasing trend in laminamivir use during 2010-2017, a temporal increase in baloxavir use in 2018. Symptomatic medications with serious side effects (codeine, salicylate, sedative antihistamine) showed decreasing trends over the study period.

CONCLUSIONS

Influenza incidence and healthcare resource use were largely affected by the 2009 influenza pandemic and the COVID-19 pandemic. Our study indicates improvement of quality in healthcare delivered to children.

Sex differences in susceptibility to influenza A virus infection depend on host genotype

Infection with the respiratory pathogen influenza A virus (IAV) causes significant morbidity and mortality each year. While host genotype is thought to contribute to severity of disease, naturally occurring genetic determinants remain mostly unknown. Moreover, more severe disease is seen in women compared with men, but genetic mechanisms underlying this sex difference remain obscure. Here, using IAV infection in a mouse model of naturally selected genetic diversity, namely C57BL6/J (B6) mice carrying chromosomes (Chr) derived from the wild-derived and genetically divergent PWD/PhJ (PWD) mouse strain (B6.Chr^PWD consomic mice), we examined the effects of genotype and sex on severity of IAV-induced disease. Compared with B6, parental PWD mice were completely protected from IAV-induced disease, a phenotype that was fully recapitulated in the B6.Chr16^PWD strain carrying the PWD-derived allele of Mx1. In contrast, several other consomic strains, including B6.Chr3^PWD and B6.Chr5^PWD, demonstrated greatly increased susceptibility. Notably, B6.Chr5^PWD and B6.ChrX.3^PWD strains, the latter carrying the distal one-third of ChrX from PWD, exhibited increased morbidity and mortality specifically in male but not female mice. Follow up analyses focused on B6 and B6.ChrX.3^PWD strains demonstrated moderately elevated viral load in B6.ChrX3^PWD male, but not female mice. Transcriptional profiling demonstrated genotype- and sex-specific gene expression profiles in the infected lung, with male B6.ChrX.3 mice exhibiting the most significant changes, including upregulation of a proinflammatory gene expression program associated with myeloid cells, and altered sex-biased expression of several X-linked genes that represent positional candidates, including Tlr13 and Slc25a53. Taken together, our results identify novel loci on autosomes and the X chromosome regulating IAV susceptibility and demonstrate that sex differences in IAV susceptibility are genotype-dependent, suggesting that future genetic association studies need to consider sex as a covariate.

Human Susceptibility to Influenza Infection and Severe Disease

Influenza viruses are a persistent threat to global human health. Increased susceptibility to infection and the risk factors associated with progression to severe influenza-related disease are determined by a multitude of viral, host, and environmental conditions. Decades of epidemiologic research have broadly defined high-risk groups, while new genomic association studies have identified specific host factors impacting an individual's response to influenza. Here, we review and highlight both human susceptibility to influenza infection and the conditions that lead to severe influenza disease.

Dynamic Propagation and Impact of Pandemic Influenza A (2009 H1N1) in Children: A Detailed Review

Influenza is a highly contagious respiratory infection caused by the circulating Swine flu virus. According to the World Health Organization (WHO), the unique blending strain of influenza A H1N1 2009 (Swine Flu) is a pandemic affecting several geographical regions, including India. Previous literature indicates that children are "drivers" of influenza pandemics. At present, satisfactory data were not available to accurately estimate the role of children in the spread of influenza (in particular 2009 pandemic influenza). However, the role of children in the spread of pandemics influenza is unclear. Several studies in children have indicated that the immunization program decreased the occurrence of influenza, emphasizing the significance of communities impacted by global immunization programs. This article provides a brief overview on how children are a key contributor to pandemic Influenza A (2009 H1N1) and we would like to draw your attention to the need for a new vaccine for children to improve disease prevention and a positive impact on the community.

Genetic variation in chromosome Y regulates susceptibility to influenza A virus infection

Males of many species, ranging from humans to insects, are more susceptible than females to parasitic, fungal, bacterial, and viral infections. One mechanism that has been proposed to account for this difference is the immunocompetence handicap model, which posits that the greater infectious disease burden in males is due to testosterone, which drives the development of secondary male sex characteristics at the expense of suppressing immunity. However, emerging data suggest that cell-intrinsic (chromosome X and Y) sex-specific factors also may contribute to the sex differences in infectious disease burden. Using a murine model of influenza A virus (IAV) infection and a panel of chromosome Y (ChrY) consomic strains on the C57BL/6J background, we present data showing that genetic variation in ChrY influences IAV pathogenesis in males. Specific ChrY variants increase susceptibility to IAV in males and augment pathogenic immune responses in the lung, including activation of proinflammatory IL-17-producing γδ T cells, without affecting viral replication. In addition, susceptibility to IAV segregates independent of copy number variation in multicopy ChrY gene families that influence susceptibility to other immunopathological phenotypes, including survival after infection with coxsackievirus B3. These results demonstrate a critical role for genetic variation in ChrY in regulating susceptibility to infectious disease.

Quantitative detection of Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae in patients with new influenza A (H1N1)/2009 and influenza A/2010 virus infection

INTRODUCTION

Viral influenza is a seasonal infection associated with significant morbidity and mortality. In the United States more than 35,000 deaths and 200,000 hospitalizations are recorded annually due to influenza. Secondary bacterial infections or co-infections associated with cases of influenza are a leading cause of severe morbidity and mortality, especially among high-risk groups such as the elderly and young children.

AIM

The aim of the present study was the quantitative detection of S. aureus, S. pneumoniae and H. influenzae in a group of patients with seasonal influenza A, influenza A (H1N1) pandemic 2009, and patients with symptoms of respiratory infection, but the negative for H1N1 serving as control group.

METHOD

In total, 625 patients suspected respiratory infection from April 2009 to April 2010 were studied. There were 58 patients with influenza A H1N1 and 567 patients negative for influenza A H1N1. From November 2010 to February 2011, 158 patients with respiratory symptoms were analyzed for seasonal influenza A. There were 25 patients with seasonal influenza A. To check the colonization status among the healthy individuals 62 healthy persons were further investigated. Individual were screened in parallel. The choices of special genes were amplified from clinical specimens using real-time PCR with a cutoff of 10(4) CFU/mL to differentiate colonization from infection in respiratory tract.

RESULTS

S. aureus, S. pneumoniae and H. influenzae were detected in 12%, 26% and 33% of patients with H1N1, while the corresponding figures were 9%, 19%, and 31% for H1N1 negative patients. Among patients with seasonal influenza A 12% S. aureus, 24% S. pneumoniae, and 32% H. influenzae co-infections were detected, while influenza negative control group yielded 5% S. aureus, 11% S. pneumoniae, and 10% H. influenzae, respectively.

CONCLUSION

The results of this study indicated that the serotype of pandemic H1N1 2009 did not increase incidence of secondary infection with S. aureus, S. pneumoniae and H. influenzae. Quantitative detection of secondary bacterial infection by QR-PCR can help us for distinguishing colonization from infection and controlling misuse of antibiotics and bacterial drug resistances.

Secondary infection and clinical aspects after pandemic swine-origin influenza a (H1N1) admission in an Iranian critical care unite

Objective:

A new flu virus (H1N1) swine origin and cause of human infection with acute lung disease was published in the world and led to many patients were admitted in intensive care unit (ICU).

Materials and Methods:

In a prospective descriptive study, all ICU patients in a pulmonary disease specialist hospital between April 2010 and July 2011 with confirmed infection (H1N1) were evaluated. Information including demographic, clinical and microbiology using Statistical Package for Social Sciences (SPSS) software version 16 was studied and classified.

Results:

Of 46 patients hospitalized with confirmed diagnosis of swine flu pneumonia (H1N1), 20 cases (43.7%) admitted in ICU out of which 10 cases were males (50%), the mean age was 36.9 and the range was 21-66 years. Nine patients (45%) had underlying diseases. Most underlying disease was respiratory disease in which four cases (20%) were of asthma and one patient had chronic obstructive pulmonary disease (COPD). No admission of pregnant patient with swine flu was reported in the ICU. Cough and sputum were the most frequent symptoms (19 patients equal 95%). Four patients (20%) were admitted with decreased level of consciousness and five cases (25%) died during hospitalization.

Conclusion:

It seems, swine flu with high mortality and transfer rates is a worldwide health problem. Because of limited treatment regimen, the risk of secondary infection and high need to intensive care in H1N1 pneumonia, environmental control, including vaccination of high risk people and public announcement, make determining role in controlling of this disease.

Comparisons of clinical characteristics between adult patients with 2009 H1N1 influenza and those with seasonal influenza during the 2009 epidemic in Thailand

Clinical presentations of patients with 2009 H1N1 influenza are generally similar to those of patients with seasonal influenza. A cross-sectional study was conducted among adults at an outpatient clinic in a university hospital setting during the 2009 epidemic. Infections in all patients were confirmed by real-time reverse transcription-polymerase chain reaction. There were 269 patients with 2009 H1N1 influenza and 128 patients with seasonal influenza. Compared with patients with seasonal influenza, patients with 2009 H1N1 influenza were more likely to be aged <20 years (25.7% vs. 8.6%, P < 0.001) and to be students (38.7% vs. 22.0%, P = 0.001), or healthcare workers (20.1% vs. 10.9%, P = 0.022); however, they were less likely to have an underlying disease (25.6% vs. 39.8%, P = 0.004) and influenza vaccination (4.2% vs. 12.2%, P = 0.021). There were no differences in the illness duration, vital signs, and symptoms between groups. Patients with seasonal influenza were more likely to be admitted to the intensive care unit (2.4% vs. 0%, P = 0.033) and exhibited a higher mortality rate (2.4% vs. 0%, P = 0.093). A history of contact with a confirmed 2009 H1N1 influenza case (odds ratio [OR] = 12.91, P < 0.001) and age (OR = 1.05 per 10 years younger, P = 0.015) were associated with 2009 H1N1 influenza infections. In conclusion, these results showed differences in characteristics between the patients with 2009 H1N1 influenza and those with seasonal influenza.

Characterisation of acute respiratory infections at a United Kingdom paediatric teaching hospital: observational study assessing the impact of influenza A (2009 pdmH1N1) on predominant viral pathogens

Background

According to the World Health Organisation, influenza A (2009 pdmH1N1) has moved into the post-pandemic phase, but there were still high numbers of infections occurring in the United Kingdom in 2010-11. It is therefore important to examine the burden of acute respiratory infections at a large children’s hospital to determine pathogen prevalence, occurrence of co-infection, prevalence of co-morbidities and diagnostic yield of sampling methods.

Methods

This was a retrospective study of respiratory virus aetiology in acute admissions to a paediatric teaching hospital in the North West of England between 1st April 2010 and 31st March 2011. Respiratory samples were analysed either with a rapid RSV test if the patient had symptoms suggestive of bronchiolitis, followed by multiplex PCR testing for ten respiratory viruses, or with multiplex PCR testing alone if the patient had suspected other ARI. Patient demographics and data regarding severity of illness, presence of co-morbidities and respiratory virus sampling method were retrieved from case notes.

Results

645 patients were admitted during the study period. 82/645 (12.7%) patients were positive for 2009 pdmH1N1, of whom 24 (29.2%) required PICU admission, with 7.3% mortality rate. Viral co-infection occurred in 48/645 (7.4%) patients and was not associated with more severe disease. Co-morbidities were present more frequently in older children, but there was no significant difference in prevalence of co-morbidity between 2009 pdmH1N1 patients and those with other ARI. NPA samples had the highest diagnostic yield with 192/210 (91.4%) samples yielding an organism.

Conclusions

Influenza A (2009 pdmH1N1) is an ongoing cause of occasionally severe disease affecting both healthy children and those with co-morbidities. Surveillance of viral pathogens provides valuable information on patterns of disease.

Distinct differences in clinical manifestation and viral laboratory parameters between children and adults with influenza A(H1N1)pdm09 infection--a retrospective comparative analysis

During the influenza pandemic 2009 children and adults differed in the clinical course of the influenza disease. In following the question arose, if the case definitions used within the national and international organizations are an adequate tool for the clinical diagnosis of influenza in children as well as in adults. Therefore medical charts from 146 children and 229 adults were retrospectively analyzed. In addition, the initial viral loads of all 375 patients and the duration of virus shedding of a subset of 79 patients were also investigated. Children show a wider clinical spectrum including gastro enteric symptoms and also a different spectrum of laboratory parameters like elevated CRP-levels, leucocytosis, and higher viral loads. Further, children show significantly more often complications, for example, myositis that may be underdiagnosed. In patients receiving antiviral-therapy complications occurred significantly less often and the presence of symptoms was significantly shorter compared to the untreated group (2.3 days vs. 6.0 days). In summary, the differences in the clinical picture between children and adults should be taken into consideration for the clinical diagnosis of influenza and also for a future discussion on age specific influenza case definitions.

Elucidation and clinical role of emerging viral respiratory tract infections in children

Acute respiratory viral infections (ARVI's) are the most common infectious disease in humans. With the appearance of molecular techniques the recovery of viruses has dramatically increased. Nowadays virologists can quickly discriminate virological families and related viruses from emerging viruses and consequently identify novel viruses. Many new respiratory viruses have been identified in children in the past 15 years. In this review we shortly discuss novel respiratory viruses and their pathogenic role in pediatric respiratory disease. Advantages and drawbacks of the technique and our current knowledge will be discussed. We will conclude this review with a general discussion on the future role of molecular diagnostic virology in the clinic.

Hospitalized children with influenza A H1N1 (2009) infection: a Spanish multicenter study

OBJECTIVES

Even though the majority of cases of influenza A H1N1 (2009) in children are mild, severe complications have been reported. Our objective was to describe the Influenza A H1N1 (2009) complications in pediatric population in Spain.

METHODS

This was a multicenter descriptive study including patients younger than 14 years attending 15 emergency departments and hospitalized with laboratory-confirmed influenza A H1N1 (2009) infection from August to December 2009. Patients who did not meet any of the admission criteria recommended by the Health Spanish Authorities were excluded. A standardized report form was used to collect information on demographics, risk factors, clinical and microbiological data, treatment, and outcome. Potential risk factors associated with intensive care requirement (assisted ventilation and/or inotropic support) were analyzed.

RESULTS

Three hundred eight patients were included. The hospitalization rate was 20.5 per 100,000 children younger than 14 years. Median age was 48 months; 21% had underlying medical conditions. The most common diagnosis at admission was presumed bacterial pneumonia (42.5%). Oseltamivir was prescribed on admission to 207 children (67.2%) and antibiotics to 199 (64.6%). Bacterial coinfection was confirmed in 29 patients (9.4%). Fifty-four patients (17.5%) were admitted to an intensive care unit, and 6 (1.9%) died. Logistic regression model revealed that confirmed bacterial coinfection was associated with intensive care requirement (odds ratio, 3.3; 95% confidence interval, 1.1-10.0).

CONCLUSIONS

Respiratory manifestations were the main complication described. Although the majority of patients had a favorable evolution, a remarkable morbidity and mortality were observed. Patients with confirmed bacterial coinfection were at high risk of severe illness.

Oseltamivir pharmacokinetics, dosing, and resistance among children aged <2 years with influenza

BACKGROUND

Children <2 years of age are at high risk of influenza-related mortality and morbidity. However, the appropriate dose of oseltamivir for children <2 years of age is unknown.

METHODS

The National Institute of Allergy and Infectious Diseases Collaborative Antiviral Study Group evaluated oseltamivir in infants aged <2 years in an age-de-escalation, adaptive design with a targeted systemic exposure.

RESULTS

From 2006 to 2010, 87 subjects enrolled. An oseltamivir dose of 3.0 mg/kg produced drug exposures within the target range in subjects 0-8 months of age, although there was a greater degree of variability in infants <3 months of age. In subjects 9-11 months of age, a dose of 3.5 mg/kg produced drug exposures within the target range. Six of 10 subjects aged 12-23 months receiving the Food and Drug Administration-approved unit dose for this age group (ie, 30 mg) had oseltamivir carboxylate exposures below the target range. Virus from 3 subjects developed oseltamivir resistance during antiviral treatment.

CONCLUSIONS

The appropriate twice-daily oral oseltamivir dose for infants ≤8 months of age is 3.0 mg/kg, while the dose for infants 9-11 months old is 3.5 mg/kg.

Relação entre morbidade hospitalar e cobertura vacinal contra Influenza A

OBJETIVO: Analisar o perfil dos indivíduos acometidos pelo vírus Influenza A (H1N1), e o impacto vacinal nos grupos prioritários à vacinação. MÉTODOS: Estudo ecológico, observacional, de caráter retrospectivo, com população de indivíduos residentes na cidade de Maringá-PR e submetidos à internação por Influenza A entre 2009 e 2010. RESULTADOS: No ano de 2009, ocorreram 614 internações decorrentes de infecção pelo vírus Influenza A em Maringá-PR. A disponibilização da vacina fez com que o número de acometidos diminuísse para 169 em 2010, ocorrendo impacto vacinal nos seguintes grupos populacionais: gestantes, portadores de doenças crônicas e adultos de 20 a 39 anos. CONCLUSÃO: Identificou-se a necessidade de estender a faixa etária de vacinação para crianças de 2 a 4 anos e preenchimento dos impressos de vacinação dos indivíduos e grupos vacinados com maior rigor.

Pediatric hospitalizations with influenza A infection during the 2009-2010 pandemic in five hospitals in Japan

BACKGROUND

The aim of this study was to identify the clinical characteristics of hospitalized children with the 2009 pandemic influenza virus infection in Japan.

METHODS

We retrospectively reviewed cases of hospitalized children younger than 16 years with laboratory-confirmed influenza A virus infection during the 2009-2010 pandemic season in five hospitals in Japan.

RESULTS

A total of 515 cases were included in the analysis. The median age was 6.3 years (range 0-15), and 216 subjects (41.9%) had one or more underlying medical conditions. There were no fatalities, but 16 patients (3.1%) required intensive care. More than 93% of the subjects received neuraminidase inhibitors, and more than 87% received these medications within 48 h of the onset of symptoms. Approximately 80% of all subjects were admitted to hospital within 48 h of the onset of symptoms.

CONCLUSIONS

There were no fatalities, and the proportion of patients with serious illness was substantially lower than previously reported from other countries. Good access to medical services and proactive treatment may have contributed to the lower disease burden of the 2009 influenza pandemic on Japanese children.

First-year experience of a Brazilian tertiary medical center in supporting severely ill patients using extracorporeal membrane oxygenation

OBJECTIVES

The aim of this manuscript is to describe the first year of our experience using extracorporeal membrane oxygenation support.

METHODS

Ten patients with severe refractory hypoxemia, two with associated severe cardiovascular failure, were supported using venous-venous extracorporeal membrane oxygenation (eight patients) or veno-arterial extracorporeal membrane oxygenation (two patients).

RESULTS

The median age of the patients was 31 yr (range 14-71 yr). Their median simplified acute physiological score three (SAPS3) was 94 (range 84-118), and they had a median expected mortality of 95% (range 87-99%). Community-acquired pneumonia was the most common diagnosis (50%), followed by P. jiroveci pneumonia in two patients with AIDS (20%). Six patients were transferred from other ICUs during extracorporeal membrane oxygenation support, three of whom were transferred between ICUs within the hospital (30%), two by ambulance (20%) and one by helicopter (10%). Only one patient (10%) was anticoagulated with heparin throughout extracorporeal membrane oxygenation support. Eighty percent of patients required continuous venous-venous hemofiltration. Three patients (30%) developed persistent hypoxemia, which was corrected using higher positive end-expiratory pressure, higher inspired oxygen fractions, recruitment maneuvers, and nitric oxide. The median time on extracorporeal membrane oxygenation support was five (range 3-32) days. The median length of the hospital stay was 31 (range 3-97) days. Four patients (40%) survived to 60 days, and they were free from renal replacement therapy and oxygen support.

CONCLUSIONS

The use of extracorporeal membrane oxygenation support in severely ill patients is possible in the presence of a structured team. Efforts must be made to recognize the necessity of extracorporeal respiratory support at an early stage and to prompt activation of the extracorporeal membrane oxygenation team.

Influenza A (H1N1): a rare cause of deafness in two children

OBJECTIVE

We report deafness occurring as an extremely rare complication of influenza A caused by the H1N1 virus ('swine flu'), in two children.

METHODS

Case reports and review of the literature concerning influenza A (H1N1) and acquired viral infection causing deafness.

RESULTS

Two children with normal hearing developed bilateral deafness following influenza A (H1N1). The diagnosis was confirmed using polymerase chain reaction. Both patients were treated with oseltamivir.

CONCLUSION

Following a review of the literature, these two patients appear to be the first reported cases of bilateral deafness following influenza A (H1N1).

Influenza A H1N1/2009 infection in pediatric solid organ transplant recipients

AIM AND METHOD

The aim of this study was to describe the clinical characteristics and outcome of pandemic influenza A H1N1/2009 (pH1N1) infection, in a retrospective cohort of pediatric patients with kidney and/or liver transplant and confirmed pH1N1 infection from June to December 2009, diagnosed in 2 Spanish teaching hospitals.

RESULTS

Forty-nine patients were included. Pneumonia was diagnosed in 4 patients (8.2%), and 3 of them required respiratory support. There were no related deaths.

CONCLUSION

Antiviral treatment within 48 h was associated with a lower likelihood of pneumonia (0/38, 0%) than treatment started after 48 h (4/11, 36.3%) (P < 0.01).

Clinical characteristics of pediatric hospitalizations associated with 2009 pandemic influenza A (H1N1) in Northern Bavaria, Germany

Background

The 2009 pandemic influenza A (H1N1) (PIA) virus infected large parts of the pediatric population with a wide clinical spectrum and an initially unknown complication rate. The aims of our study were to define clinical characteristics and outcome of pandemic influenza A (H1N1) 2009-associated hospitalizations (PIAH) in children <18 years of age. All hospitalized cases of children <18 years of age with laboratory-confirmed pandemic influenza A (H1N1) 2009 in the region of Wuerzburg (Northern Bavaria, Germany) between July 2009 and March 2010 were identified. For these children a medical chart review was performed to determine their clinical characteristics and complications.

Results

Between July 2009 and March 2010, 94 PIAH (62% males) occurred in children <18 years of age, with a median age of 7 years (IQR: 3–12 years). Underlying diseases and predisposing factors were documented in 40 (43%) children; obesity (n = 12, 30%), asthma (n = 10, 25%) and neurologic disorders (n = 8, 20%) were most frequently reported. Sixteen (17%) children received oxygen supplementation; three (3%) children required mechanical ventilation. Six (6%) children were admitted to an intensive care unit, four of them with underlying chronic diseases.

Conclusions

Most PIAH demonstrated a benign course of disease. However, six children (6%) needed treatment at an intensive care unit for severe complications.

Other viral infections in solid organ transplantation

Viral infections are a major cause of morbidity and even mortality in solid organ transplant recipients. This article reviews key aspects of infections in solid organ transplant recipients from respiratory viruses, such as influenza, polyomavirus, erythrovirus B19 and measles.

Neonatal influenza A/H1N1/2009 outbreak in a UK district general hospital

Increasing numbers of cases of neonatal influenza A/H1N1/2009 are being reported in the literature but there are no specific guidelines on outbreak management. We report an outbreak of influenza A/H1N1/2009 in a newborn intensive care unit in a large district general hospital. The index case probably acquired the infection from the mother. Subsequently two other babies were infected, possibly due to the use of continuous positive airway pressure ventilation. The outbreak was brought under control with enhanced surveillance and screening of contacts, isolation of confirmed cases and the use of oseltamivir.

Predictors of mortality in hospitalized children with pandemic H1N1 influenza 2009 in Pune, India

OBJECTIVE

To analyse the factors associated with increased mortality among Indian Children with H1N1.

METHODS

Data were abstracted from available hospital records of children less than 12 y of age, who were admitted to Sassoon General Hospital in Pune, India, with confirmed pandemic 2009 H1N1 influenza infection from August 2009 through January 2010. Logistic regression analysis was used to identify clinical characteristics associated with mortality.

RESULTS

Of 775 pediatric cases admitted with Influenza Like Illness (ILI), 92 (11.8%) had confirmed H1N1 influenza infection. The median age of HIN1 cases was 2.5 y; 13 (14%) had an associated co-morbid condition. Median duration of symptoms was 4 d (interquartile range (IQR), 3-7 d). All 92 H1N1 cases received oseltamivir and empiric antimicrobials on admission. Intensive care unit (ICU) admission was required for 88 (96%) children, and 20 (23%) required mechanical ventilation.Fifteen children (16%) died; mortality was associated with presence of diffuse alveolar infiltrate on admission chest radiography (odds ratio (OR) 45, 95%CI :5.4-370; p < 0.001), use of corticosteroids in ARDS in children who required mechanical ventilation (OR 8.12, 95%CI: 2.44-27.05; p = 0.001), SpO(2) <80% on admission (OR 32.8, 95% CI: 5.8-185.5; p < 0.001) and presence of ARDS (OR 345.3, 95% CI :33.5-3564.1; p < 0.001). Necropsy from all children who died showed 9 (60%) had ARDS pattern and necrotizing pneumonitis, diffuse hemorrhage and interstitial pneumonia (n = 4 each, 27%) with gram positive organisms consistent with severe viral and bacterial co-infection.

CONCLUSIONS

Hypoxia, ARDS and use of corticosteroids in children with ARDS who were mechanically ventilated were the factors associated with increased odds of mortality. Necropsy also suggested bacterial co-infection as a risk factor.

Characterization of 2009 H1N1 pandemic influenza in a population of Dutch children with influenza-like signs and symptoms

Aim:  To determine causative respiratory pathogens and describe epidemiological and clinical characteristics in a paediatric population with influenza‐like illness during the 2009 H1N1‐pandemic.

Methods:  Observational study of 412 children visiting an outpatient clinic of a Dutch teaching hospital.

Results:  From August to December 2009, 412 children were tested at the clinic; 32% proved H1N1‐positive, confirmed by reverse‐transcriptase‐polymerase‐chain‐reaction (RT‐PCR). Pathogens were detected in 65% of samples. Influenza A(H1N1) (n = 132), human rhinovirus (n = 55), respiratory syncytial virus (n = 45) and adenovirus (n = 34) were mostly identified. Co‐infections were seen in 34 children (8.3%). Mean age was 6.8 and 4.2 years in H1N1‐positive and H1N1‐negative cases, respectively (p < 0.01). H1N1‐positive outpatient children reported fever, cough and rhinorrhoea more frequently than their H1N1‐negative counterparts. Of 72 hospitalized children, 31% proved H1N1‐positive; all showed a relatively mild clinical illness. None of the children had been admitted to an intensive care unit or died. Oseltamivir treatment was initiated in 72 children and discontinued in 42 (63%) when RT‐PCR results turned negative.

Conclusion:  The 2009 H1N1‐pandemic showed a mild clinical course in a Dutch paediatric outpatient clinic population. Respiratory pathogens were detected in the majority of children with influenza‐like illness and influenza A(H1N1) virus was identified in one‐third. Testing symptomatic children during an influenza pandemic has effectively limited the use of oseltamivir.

Features associated with severe disease in hospitalized children with 2009 influenza A (H1N1) infection at a university hospital in Riyadh, Saudi Arabia

BACKGROUND AND OBJECTIVES

In 2009, pandemic H1N1 influenza A caused significant morbidity and mortality worldwide; however, available data on disease characteristics and outcome of hospitalized children is limited.

DESIGN AND SETTING

A prospective cohort study of children who required hospitalization because of the influenza A (H1N1) infection at King Khalid University Hospital in Riyadh, Saudi Arabia, over 6 months (July- December, 2009).

PATIENTS AND METHODS

Data was collected using a predesigned form for all admitted pediatric cases (0-12 years) presenting with the influenza-like illness and who tested positive for the novel influenza (H1N1) using reverse transcriptase polymerase chain reaction assay. The clinical course and features associated with the severe disease among such children were described

RESULTS

Out of 1103 children with the influenza-like illness, 375 (34%) were confirmed pediatric cases of influenza A (H1N1), of whom 50 (13.3%) required hospitalization. The median age was 3 years (range, 1 month-12 years). Fever was the most frequent symptom (94%) at admission, followed by cough (86%) and other symptoms including vomiting and diarrhea. The majority (70%) of children had at least one underlying medical condition, with bronchial asthma being the most common (40%). All cases were treated with oseltamivir. Five children (10%) were admitted to the ICU, 4 required mechanical ventilation, and 2 died (4%).

CONCLUSIONS

The majority of children with 2009 H1N1 influenza A-associated hospitalization in this series had an uncomplicated course. Respiratory complications and ICU admissions were more frequent in those with underlying disease, especially asthma and neuromuscular diseases. Efforts need to be focused prior to each influenza season and special emphasis needs to be given to children by immunizing them with H1N1 influenza A vaccination to avoid severe disease and minimize complications.

Critically ill children with pandemic influenza (H1N1) in pediatric intensive care units in Turkey

OBJECTIVES

To outline the epidemiologic features, clinical presentation, clinical courses, and outcomes in critically ill children with pandemic influenza in pediatric intensive care units.

DESIGN

Retrospective, observational, multicenter study.

SETTING

Thirteen tertiary pediatric intensive care units in Turkey.

PATIENTS

Eighty-three children with confirmed infection attributable to pandemic influenza detected by reverse-transcriptase polymerase chain reaction assay between November 1 and December 31, 2009 who were admitted to critical care units.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During a 2-month period, 532 children were hospitalized with pandemic influenza and 83 (15.6%) needed critical care. For the 83 patients requiring critical care, the median age was 42 (range, 2-204) months, with 24 (28.9%) and 48 (57.8%) of patients younger than 2 and 5 yrs, respectively. Twenty (24.1%) patients had no underlying illness, but 63 (75.9%) children had an underlying chronic illness. Indications for admission to the pediatric intensive care unit were respiratory failure in 66 (79.5%), neurologic deterioration in six (7.2%), and gastrointestinal symptoms in five (6.0%) patients. Acute lung injury was diagnosed in 23 (27.7%), acute respiratory distress syndrome was diagnosed in 34 (41%), and 51 (61.4%) patients were mechanically ventilated. Oseltamivir was used in 80 (96%) patients. The mortality rate for children with pandemic influenza 2009 was 30.1% compared to an overall mortality rate of 13.7% (p = .0016) among pediatric intensive care unit patients without pandemic influenza during the study period. Also, the mortality rate was 31.7% in patients with comorbidities and 25.0% in previously healthy children (p = .567). The cause of death was primary pandemic influenza infection in 16 (64%), nosocomial infection in four (16%), and primary disease progression in five (20%) patients. The odds ratio for respiratory failure was 14.7 (95% confidence interval, 1.85-111.11), and odds ratio for mechanical ventilation was 27.7 (95% confidence interval, 0.003-200).

CONCLUSIONS

Severe disease and high mortality rates were seen in children with pandemic influenza. Death attributable to pandemic influenza occurred in all age groups of children with or without underlying illness. Multiple organ dysfunction syndrome is associated with increased mortality, and death is frequently secondary to severe lung infection caused by pandemic influenza.

Epidemiology and clinical presentation of pandemic influenza A (H1N1) among hospitalized children in Kuwait

OBJECTIVE

To describe the epidemiological and clinical characteristics of children hospitalized for the 2009 influenza A H1N1 infection in Kuwait.

MATERIALS AND METHODS

A retrospective chart review of hospitalized children with laboratory-confirmed influenza A H1N1 infection in two hospitals in Kuwait was conducted. Epidemiological characteristics, clinical features, risk factors for severe disease, complications and mortality were analyzed.

RESULTS

The medical records of 197 children hospitalized for the 2009 pandemic H1N1 infection from August 2009 to January 2010 were reviewed. The majority of the children (104; 52.8%) were admitted during the month of October. The median age was 2 years. Most of the admitted children were in two age categories: 64 infants ≤1 year (32%) and 62 schoolchildren >5 years (31%). The most frequent presentations were fever in 193 (98%), cough in 155 (79%) and runny nose in 105 (53%) cases. The majority of the admitted children (109; 55%) had been previously healthy. All children received an antiviral agent (oseltamivir), and antibiotics were administered to 147 (75%). Bacterial co-infections occurred in 3 (1.5%) of all hospitalized children. Six (3%) children were admitted to the intensive care unit, of whom 4 (66%) required artificial ventilation. There was only 1 mortality.

CONCLUSIONS

The pandemic H1N1 infection was associated with a wide spectrum of clinical manifestations. The majority of hospitalized children had previously been healthy. Most of the admitted children had an uncomplicated clinical course.

Pandemic influenza A(H1N1) virus infection in solid organ transplant recipients: impact of viral and non-viral co-infection

Solid organ transplant recipients (SOTR) are at risk of serious influenza-related complications. The impact of respiratory co-infection in SOTR with 2009 pandemic influenza A(H1N1) is unknown. A multicentre prospective study of consecutive cases of pandemic influenza A(H1N1) in SOTR was carried out to assess the clinical characteristics and outcome and the risk factors for co-infection. Overall, 51 patients were included. Median time from transplant was 3.7 years, 5.9% of the cases occurred perioperatively and 7.8% were hospital-acquired. Pneumonia was diagnosed in 15 (29.4%) patients. Ten cases were severe (19.6%): 13.7% were admitted to intensive care units, 5.9% suffered septic shock, 5.9% developed acute graft rejection and 7.8% died. Co-infection was detected in 15 patients (29.4%): eight viral, six bacterial and one fungal. Viral co-infection did not affect the outcome. Patients with non-viral co-infection had a worse outcome: longer hospital stay (26.2 ± 20.7 vs. 5.5 ± 10.2) and higher rate of severe diseases (85.7% vs. 2.3%) and mortality (42.8% vs. 2.3%). Independent risk factors for non-viral co-infection were: diabetes mellitus and septic shock. Other factors associated with severe influenza were: delayed antiviral therapy, diabetes mellitus, time since transplantation <90 days and pneumonia. In conclusion, pandemic influenza A can cause significant direct and indirect effects in SOTR, especially in the early post-transplant period, and should be treated early. Clinicians should be aware of the possibility of non-viral co-infection, mainly in diabetic patients and severe cases. An effort should be made to prevent influenza with immunization of the patient and the environment.

The use of antiviral drugs for influenza: Guidance for practitioners 2012/2013

The present article addresses the use of antiviral drugs in the management of seasonal influenza illness for the 2012/2013 season. It updates the previous document published in 2011 (1). Noteworthy guidance updates since 2011 include the following: Seasonal influenza in 2012/2013 is predicted to be caused by two human influenza A and one influenza B strain, all of which are anticipated to remain generally susceptible to oseltamivir.The predicted strains are A/California/7/2009 (H1N1) pdm09-like, A/Victoria/361/2011 (H3N2)-like and B/Wisconsin/1/2010-like (Yamagata lineage). All are included in the seasonal influenza vaccine and are susceptible to oseltamivir.Swine-variant H3N2v, which has rarely caused infection in humans exposed to infected swine within the past year in the United States, is susceptible to oseltamivir. It is not included in the current seasonal influenza vaccine.It is still considered that initiation of antiviral therapy more than 36 h to 48 h after onset of symptoms is beneficial in patients hospitalized with complicated influenza and severe illness.Oseltamivir continues to be recommended for the treatment of influenza in pregnant women.The use of antiviral drugs among measures to control outbreaks of influenza in closed facilities such as correctional institutions is now included in the present document.

A scoring system for predicting results of influenza rapid test in children: a possible model facing overwhelming pandemic infection

Background

The pandemic novel influenza H1N1 (swine) influenza A virus (H1N1v) infection has caused large-scale community infection in Taiwan. Anxiety developed in the general public and physicians faced a huge challenge in many aspects. We conducted this prospective study to develop a scoring system based on the clinical manifestations for predicting the results of influenza rapid testing, as a surrogate of influenza rapid testing, to lower the anxiety and decrease the burden for the test.

Methods

From September 1, 2009 to October 5, 2009, pediatric patients who received influenza rapid tests were enrolled, and questionnaires were recorded and analyzed in the first 2 weeks. A further scoring system was conducted to predict the results of influenza rapid tests and validated in the next 3 weeks.

Results

Eight hundred and forty-five children were enrolled in our study. In the first phase, data from 506 patients showed that those with age ≥ 5 years, fever ≥ 38°C, contact history of influenza A infection, myalgia, lethargy, sore throat, cough, and headache had a higher risk of positive results (odds ratio: 1.1–2.53). A scoring system was designed, with ≥5 points indicating acceptable sensitivity (69.5%) and specificity (63.6%). Three hundred and thirty-nine patients in the second phase were enrolled to validate the scoring system and the positive and negative predictive values were 52.0% and 73.8%.

Conclusion

The emergence of H1N1v infection is not only an important medical issue, but also a socioeconomic problem. Based on easily available clinical information, we develop a scoring system as a preliminary screening tool for the general public and first-line health care providers to evaluate the possibility of influenza virus infection. Although this study was limited by the sensitivity of rapid tests, this type of model may be a surrogate weapon when faced with overwhelming pandemic infection in the future, especially in areas with scarce medical resources.

Critically ill children during the 2009-2010 influenza pandemic in the United States

BACKGROUND

The 2009 pandemic influenza A (H1N1) (pH1N1) virus continues to circulate worldwide. Determining the roles of chronic conditions and bacterial coinfection in mortality is difficult because of the limited data for children with pH1N1-related critical illness.

METHODS

We identified children (<21 years old) with confirmed or probable pH1N1 admitted to 35 US PICUs from April 15, 2009, through April 15, 2010. We collected data on demographics, baseline health, laboratory results, treatments, and outcomes.

RESULTS

Of 838 children with pH1N1 admitted to a PICU, the median age was 6 years, 58% were male, 70% had ≥1 chronic health condition, and 88.2% received oseltamivir (5.8% started before PICU admission). Most patients had respiratory failure with 564 (67.3%) receiving mechanical ventilation; 162 (19.3%) received vasopressors, and 75 (8.9%) died. Overall, 71 (8.5%) of the patients had a presumed diagnosis of early (within 72 hours after PICU admission) Staphylococcus aureus coinfection of the lung with 48% methicillin-resistant S aureus (MRSA). In multivariable analyses, preexisting neurologic conditions or immunosuppression, encephalitis (1.7% of cases), myocarditis (1.4% of cases), early presumed MRSA lung coinfection, and female gender were mortality risk factors. Among 251 previously healthy children, only early presumed MRSA coinfection of the lung (relative risk: 8 [95% confidence interval: 3.1-20.6]; P < .0001) remained a mortality risk factor.

CONCLUSIONS

Children with preexisting neurologic conditions and immune compromise were at increased risk of pH1N1-associated death after PICU admission. Secondary complications of pH1N1, including myocarditis, encephalitis, and clinical diagnosis of early presumed MRSA coinfection of the lung, were mortality risk factors.

Low adherence to influenza vaccination campaigns: is the H1N1 virus pandemic to be blamed?

Background

Over the last few months, debates about the handling of the influenza virus A (H1N1) pandemic took place, in particular regarding the change of the WHO pandemic definition, economic interests, the dramatic communication style of mass media. The activation of plans to reduce the virus diffusion resulted in an important investment of resources. Were those investments proportionate to the risk? Was the pandemic overrated? The workload of the Pediatric Emergency Room (P.E.R.) at a teaching hospital in Varese (Northern Italy) was investigated in order to evaluate the local diffusion and severity of the new H1N1 influenza epidemic.

Discussion

A 100% increase of the number of P.E.R. visits, particularly for influenza-like illness, was recorded during weeks 42-46 of 2009 (October, 17 to November, 2); the low rate of hospitalization and the mild presentation of the infection gave rise to the conclusion that the pandemic risk was overrated. Mass media communications concerning the new virus created a disproportionate fear in the population that significantly enhanced the burden of cares at the hospital. In the absence of generally implemented measures for etiological diagnosis, the actual incidence of the H1N1 infection could not be estimated. Virus identification, in fact, was limited to children showing severe symptoms after consultancy with an infectious disease specialist. The alarming nature of the communication campaign and the choice to limit etiologic diagnosis to severe cases created a climate of uncertainty which significantly contributed to the massive admissions to the P.E.R..

Summary

The communication strategy adopted by the mass media was an important element during the pandemic: the absence of clarity contributed to the spread of a pandemic phobia that appeared to result more from the sensationalism of the campaign than from infection with the novel influenza A variant of human, avian, swine origin virus. One relevant effect of the media coverage was the extremely low adherence rate to the vaccination campaign for the 2009-2010 and 2010-2011, especially among the high- risk population and health care workers. One positive consequence was, however, the spread of preventive hygiene measures, such as hand washing.

Pandemic A/H1N1v influenza 2009 in hospitalized children: a multicenter Belgian survey

Background

During the 2009 influenza A/H1N1v pandemic, children were identified as a specific "at risk" group. We conducted a multicentric study to describe pattern of influenza A/H1N1v infection among hospitalized children in Brussels, Belgium.

Methods

From July 1, 2009, to January 31, 2010, we collected epidemiological and clinical data of all proven (positive H1N1v PCR) and probable (positive influenza A antigen or culture) pediatric cases of influenza A/H1N1v infections, hospitalized in four tertiary centers.

Results

During the epidemic period, an excess of 18% of pediatric outpatients and emergency department visits was registered. 215 children were hospitalized with proven/probable influenza A/H1N1v infection. Median age was 31 months. 47% had ≥ 1 comorbid conditions. Febrile respiratory illness was the most common presentation. 36% presented with initial gastrointestinal symptoms and 10% with neurological manifestations. 34% had pneumonia. Only 24% of the patients received oseltamivir but 57% received antibiotics. 10% of children were admitted to PICU, seven of whom with ARDS. Case fatality-rate was 5/215 (2%), concerning only children suffering from chronic neurological disorders. Children over 2 years of age showed a higher propensity to be admitted to PICU (16% vs 1%, p = 0.002) and a higher mortality rate (4% vs 0%, p = 0.06). Infants less than 3 months old showed a milder course of infection, with few respiratory and neurological complications.

Conclusion

Although influenza A/H1N1v infections were generally self-limited, pediatric burden of disease was significant. Compared to other countries experiencing different health care systems, our Belgian cohort was younger and received less frequently antiviral therapy; disease course and mortality were however similar.

Supplies and equipment for pediatric emergency mass critical care

INTRODUCTION

Epidemics of acute respiratory disease, such as severe acute respiratory syndrome in 2003, and natural disasters, such as Hurricane Katrina in 2005, have prompted planning in hospitals that offer adult critical care to increase their capacity and equipment inventory for responding to a major demand surge. However, planning at a national, state, or local level to address the particular medical resource needs of children for mass critical care has yet to occur in any coordinated way. This paper presents the consensus opinion of the Task Force regarding supplies and equipment that would be required during a pediatric mass critical care crisis.

METHODS

In May 2008, the Task Force for Mass Critical Care published guidance on provision of mass critical care to adults. Acknowledging that the critical care needs of children during disasters were unaddressed by this effort, a 17-member Steering Committee, assembled by the Oak Ridge Institute for Science and Education with guidance from members of the American Academy of Pediatrics, convened in April 2009 to determine priority topic areas for pediatric emergency mass critical care recommendations.Steering Committee members established subcommittees by topic area and performed literature reviews of MEDLINE and Ovid databases. The Steering Committee produced draft outlines through consensus-based study of the literature and convened October 6-7, 2009, in New York, NY, to review and revise each outline. Eight draft documents were subsequently developed from the revised outlines as well as through searches of MEDLINE updated through March 2010.The Pediatric Emergency Mass Critical Care Task Force, composed of 36 experts from diverse public health, medical, and disaster response fields, convened in Atlanta, GA, on March 29-30, 2010. Feedback on each manuscript was compiled and the Steering Committee revised each document to reflect expert input in addition to the most current medical literature.

TASK FORCE RECOMMENDATIONS

The Task Force endorsed the view that supplies and equipment must be available for a tripling of capacity above the usual peak pediatric intensive care unit capacity for at least 10 days. The recommended size-specific pediatric mass critical care equipment stockpile for two types of patients is presented in terms of equipment needs per ten mass critical care beds, which would serve 26 patients over a 10-day period. Specific recommendations are made regarding ventilator capacity, including the potential use of high-frequency oscillatory ventilation and extracorporeal membrane oxygenation. Other recommendations include inventories for disposable medical equipment, medications, and staffing levels.

Pandemic H1N1 influenza-associated hospitalizations in children in Madrid, Spain

OBJECTIVE

To describe the epidemiological and clinical characteristics of children hospitalized with 2009 pandemic influenza (pH1N1) in Madrid, Spain.

PATIENTS/METHODS

We included patients less than 14 years of age admitted to one of 18 hospitals in Madrid, Spain, between May 1 and November 30, 2009 and diagnosed with pH1N1 by polymerase chain reaction. A retrospective chart review was conducted and data were compared by age, presence of high-risk medical conditions, and pediatric intensive care unit (PICU) admission.

RESULTS

A total of 517 pH1N1 cases were included for final analysis. One hundred and forty-two patients (27·5%) had predisposing underlying illnesses, with immunosuppression (36 children, 7%) and moderate persistent asthma (34, 6·6%) being the most common ones. Patients with underlying medical conditions had longer hospital stays [median 5, interquartile range (IQR) 3-8 days, versus median 4, IQR 3-6, P < 0·001] and required intensive care (20·4% versus 5·9%, P < 0·001) and mechanical ventilation more frequently than previously healthy children. Globally, intensive care was required for 51 patients (10%) and invasive mechanical ventilation for 12 (2%). Pediatric intensive care unit admission was significantly associated with abnormal initial chest X-ray [Odds Ratio (OR) 3·5, 95% confidence interval (CI) 1·5-8·5], underlying neurological condition (OR 3·1, CI 1·2-7·5) and immunosuppression (OR 2·9, 1·2-6·8). Five patients (0·9%) died; two with severe neurological disease, two with leukemia, and one with a malignant solid tumor.

CONCLUSIONS

Children with underlying medical conditions experienced more severe pH1N1 disease. Risk factors for admission to the PICU included underlying neurological conditions, immunosuppression and abnormal initial chest X-ray.

Otolaryngological Complications in Patients Infected with the Influenza A (H1N1) Virus

Objective. To describe bacterial upper respiratory infections in patients with influenza A (H1N1) virus during the 2009 pandemic.

Study Design. Case series with chart review.

Setting. May 17 to July 17, 2009, Clinica Las Condes, Santiago, Chile.

Subjects and Methods. Patients with clinical and/or laboratory diagnosis of influenza A (H1N1) who presented to the emergency department or other medical specialists with bacterial upper respiratory infection requiring antibiotic treatment within 2 months of influenza diagnosis.

Results. A total of 10,048 cases of influenza A (H1N1) were identified by the emergency department. All patients received oseltamivir. Fifty-four patients (0.55%) who presented with bacterial upper respiratory infection within 2 months after the diagnosis of influenza were selected. The median time to presentation with bacterial respiratory infection was 12 days. Median age was 12 years, and 51.8% were male. The most common bacterial upper respiratory infections were acute rhinosinusitis (46.4%; median age, 17 years), acute otitis media (33.9%; median age, 5 years), and pharyngotonsillitis (14.3%; median age, 17 years). Four patients were hospitalized: 3 with streptococcal tonsillitis with prolonged fever and 1 with acute otitis media who later developed pansinusitis and otomastoiditis. There were no deaths in this group of patients.

Conclusion. There were few bacterial upper respiratory infections associated with influenza A (H1N1) (0.55%). The most common infections were acute otitis media in young children and acute rhinosinusitis and pharyngotonsillitis in young adults. These complications were more often seen during the 2 months following the influenza infection than at the time of diagnosis with influenza. Outcome was favorable for all patients.

Severe Necrotizing Pneumonia Complicating Influenza A (H1N1): The Role of Immunologic Interaction

This report describes the successful management of a documented necrotizing pneumonia due to Streptococcus pneumoniae in a child with pandemic influenza A (H1N1). The importance of early recognition of bacterial superinfection in patients with influenza and the immunologic interactive mechanisms between viruses and bacteria in determining respiratory diseases are highlighted. The role of modern molecular techniques in improving diagnostic microbiology sensitivity and informing consequent clinical care is emphasized.

High success and low mortality rates with non-invasive ventilation in influenza A H1N1 patients in a tertiary hospital

Background

In 2009, an outbreak of respiratory illness caused by influenza A H1N1 virus occurred worldwide. Some patients required Intensive Care Unit (ICU) admission. The use of non-invasive ventilation (NIV) in these patients is controversial, as the aerosol dispersion may contaminate the environment and health-care co-workers.

Methods

Describe the respiratory profile, the mortality rate, and the benefit of using NIV in patients with confirmed diagnosis of influenza AH1N1 who were admitted in the ICU during the year 2009.

Results

A total of 1, 401 cases of influenza A H1N1 were confirmed in our hospital by real-time RT-PCR in 2009, and 20 patients were admitted to the ICU. The patients' ages ranged from 18 to 74 years (median of 42). Acute Respiratory Failure (ARF) was present in 70% of patients. The median Acute Physiology and Chronic Health Evaluation II score was 7 (range 7 to 25). Of the 14 patients who developed ARF, 85.7% needed NIV and 14% needed invasive MV at admission. Our success rate (41.6%) with NIV was higher than that described by others. The hospital mortality rate was 2.1%. When influenza A H1N1 arrived in Brazil, the disease was already on endemic alert in other countries. The population was already aware of the symptoms and the health-care system of the treatment. This allowed patients to be properly and promptly treated for influenza A H1N1, while health-care workers took protective measures to avoid contamination.

Conclusion

In our study we found a high success and low mortality rates with non-invasive ventilation in patients with influenza A H1N1.

Administration of the adjuvanted pH1N1 vaccine in egg-allergic children at high risk for influenza A/H1N1 disease

BACKGROUND

In Canada, the pH1N1 influenza vaccine is recommended for children, particularly those less than 5 years of age or with chronic underlying disease. The pH1N1 vaccine, which contains residual allergenic egg white proteins, may pose a risk for vaccination of egg-allergic children.

OBJECTIVE

To describe the outcome of pH1N1 influenza vaccine administration to egg-allergic children at risk for severe H1N1 disease.

DESIGN/METHOD

Prospective observational cohort study. Children identified as at high risk for egg allergy and H1N1 influenza were vaccinated using a two-dose split protocol in a controlled medical setting. Children were given an initial test dose; if no reaction was noted, the remainder of the dose was administered and the children were followed for allergic reactions. Those who tolerated the split dose and required a second dose of vaccine were offered vaccination four weeks later as one injection.

RESULTS

Sixty-two egg-allergic children considered at high risk for H1N1 disease received the adjuvanted pH1N1 vaccine. Egg allergy was diagnosed both clinically by an allergist and using skin and/or serum IgE testing. Within one hour of immunization, 2 children developed hives, 1 had a vasovagal response and 1 had a hypo-responsive episode. Fourteen children received the second H1N1 dose and 1 developed erythema and itching. There were no anaphylactic reactions.

CONCLUSION

Administration of the adjuvanted pH1N1 vaccine in egg-allergic children at risk for severe H1N1 influenza was safe when performed in a two-dose split protocol in a controlled medical setting.

Clinical characteristics of children with 2009 pandemic H1N1 influenza virus infections

BACKGROUND

Further understanding of the clinical manifestations, hospital course and treatment options of the 2009 pandemic H1N1 influenza virus (H1N1) is needed in preparation for future outbreaks.

METHODS

Seventy-three children with polymerase-chain-reaction-confirmed infections with H1N1 treated in a tertiary care medical center in Israel were included in the study. Clinical data were extracted from medical records, and analyzed by hospitalization status or the presence of underlying chronic medical conditions.

RESULTS

Prevalent symptoms were fever, cough and shortness of breath, with additional findings of conjunctivitis, seizures, chills, dizziness, purpuric rash and chest pain. Hospitalized patients were more likely to have shortness of breath (OR 26.7, 95%CI: 3.5-1150), abnormal lung auscultation (OR 11.6, 95%CI: 2.8-67), abnormal X-ray (OR 3.3, 95%CI: 1.1-9.6), and a chronic illness (OR 5.4, 95%CI: 1.8-17), compared with non-hospitalized ones. Disease manifestations were similar between children with or without chronic diseases. Only two (2.7%) children required intensive care, and no deaths were recorded. A high rate (18%) of thrombocytopenia was found. One child had rapid symptom resolution after intravenous immunoglobulin treatment.

CONCLUSION

H1N1 infection follows a mild course, even in the presence of severe underlying diseases. Abnormal respiratory findings and the presence of a chronic disease probably contributed to the decision to hospitalize patients. A rapid resolution of H1N1 symptoms after intravenous immunoglobulin treatment warrants further study, and could be a possible therapeutic option for severe cases.

Immunosuppressed patients with pandemic influenza A 2009 (H1N1) virus infection

The purpose of this paper was to prospectively characterize the clinical manifestations and outcomes of confirmed influenza A 2009 (H1N1) virus infection in immunosuppressed patients with hospital admission and compare them with those of a general population. A multicenter prospective cohort study was carried out. All adult patients admitted to 13 hospitals in Spain with confirmed influenza A 2009 (H1N1) virus infection from June 12, 2009 to November 11, 2009 were included. Risk factors for complicated influenza infection were studied in immunosuppressed patients. Overall, 559 patients were included, of which 56 were immunosuppressed, nine with solid or hematological malignancies, 18 with solid-organ transplant recipients, 13 with corticosteroid therapy, and six with other types of immunosuppression. Clinical findings at diagnosis were similar in both groups. Nineteen immunosuppressed patients had pneumonia (33.9%). Immunosuppressed patients with pandemic influenza had bacterial co-infection more frequently (17.9% vs. 6.4%, p = 0.02), specifically, gram-negative bacilli and Staphylococcus aureus infections. Mortality was higher in immunosuppressed patients (7.1% vs. 1.8%, p < 0.05). The only modifiable risk factor of complicated influenza A 2009 (H1N1) was delayed antiviral therapy. In immunosuppressed patients, influenza A 2009 (H1N1) virus infection has higher mortality than in non-immunosuppressed individuals. Bacterial co-infection is common in complicated cases.

Age-matched comparison of children hospitalized for 2009 pandemic H1N1 influenza with those hospitalized for seasonal H1N1 and H3N2

Background

A wide spectrum of clinical manifestation ranging from deaths to a mild course of disease has been reported in children infected with the 2009 pandemic H1N1 (pH1N1) influenza.

Methodology/Major Findings

We conducted an age-matched control study comparing children hospitalized for pH1N1 with historic controls infected with seasonal H1N1 and H3N2 influenza to correct for the effect of age on disease susceptibility and clinical manifestations. We also compared children with pH1N1 to children concurrently admitted for seasonal influenza during the pandemic period to adjust for differences in health-seeking behavior during the pandemic or other potential bias associated with historic controls. There was no death or intensive care admission. Children with pH1N1 were more likely to have at least one risk condition for influenza, an underlying chronic pulmonary condition, more likely to have asthma exacerbation and to be treated with oseltamivir. There was no difference in other aspects of the clinical course or outcome.

Conclusion

Disease manifestation of children hospitalized for pH1N1 infection was mild in our patient population.