Bronchiolitis-associated hospitalizations among American Indian and Alaska Native children

Epidemiology of RSV Bronchiolitis Among Young Children in Central New York Before and After the Onset of the COVID-19 Pandemic

BACKGROUND

Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of hospitalizations among infants in the United States. Unpredictability in RSV seasonality has occurred following the onset of the coronavirus disease 2019 (COVID-19) pandemic. Local surveillance networks can enhance the ability to appropriately time prophylaxis when exposure risk is highest.

METHODS

A retrospective, cohort study was conducted to describe the epidemiologic patterns of RSV disease among outpatient, emergency department and inpatient encounters in children <5 years in Central New York before and after the onset of the COVID-19 pandemic. Local data were collected from October 2015 to January 2023 and compared to state-level data. Linear regression models were used to identify clinical and sociodemographic differences before and after the pandemic.

RESULTS

Local variation in RSV seasonality was noted prior to the COVID-19 pandemic, however highly atypical circulation patterns appeared in the post-COVID-19 era. Since March 2020, patterns for local and state-defined RSV seasons have remained atypical (local season onset in 2021: week 27 and 2022: week 27; state season onset in 2021: week 31 and 2022: week 38). After adjusting for increases in testing, RSV bronchiolitis cases were not significantly different during pre- and post-pandemic eras. In comparison to the 2021 bronchiolitis season, the 2022 season had a higher proportion of RSV cases despite decreased testing.

CONCLUSIONS

Temporal patterns for RSV have shifted during the COVID-19 pandemic. Local surveillance networks may be advantageous in trending community-level RSV activity to optimize prophylaxis administration. Changes in RSV testing patterns occurred throughout the study period and should be accounted for when describing infant and childhood RSV disease.

ACUTE LOWER RESPIRATORY INFECTION IN GUARANI INDIGENOUS CHILDREN, BRAZIL

Objective:

To describe the clinical profile and treatment of Brazilian Guarani indigenous children aged less than five years hospitalized for acute lower respiratory infection (ALRI), living in villages in the states from Rio de Janeiro to Rio Grande do Sul.

Methods:

Of the 234 children, 23 were excluded (incomplete data). The analysis was conducted in 211 children. Data were extracted from charts by a form. Based on record of wheezing and x-ray findings, ALRI was classified as bacterial, viral and viral-bacterial. A bivariate analysis was conducted using multinomial regression.

Results:

Median age was 11 months. From the total sample, the ALRI cases were classified as viral (40.8%), bacterial (35.1%) and viral-bacterial (24.1%). It was verified that 53.1% of hospitalizations did not have clinical-radiological-laboratorial evidence to justify them. In the multinomial regression analysis, the comparison of bacterial and viral-bacterial showed the likelihood of having a cough was 3.1 times higher in the former (95%CI 1.11-8.70), whereas having chest retractions was 61.0% lower (OR 0.39, 95%CI 0.16-0.92). Comparing viral with viral-bacterial, the likelihood of being male was 2.2 times higher in the viral (95%CI 1.05-4.69), and of having tachypnea 58.0% lower (OR 0.42, 95%CI 0.19-0.92).

Conclusions:

Higher proportion of viral processes was identified, as well as viral-bacterial co-infections. Coughing was a symptom indicative of bacterial infection, whereas chest retractions and tachypnea showed viral-bacterial ALRI. Part of the resolution of non-severe ALRI still occurs at hospital level; therefore, we concluded that health services need to implement their programs in order to improve indigenous primary care.

Identifying Gaps in Respiratory Syncytial Virus Disease Epidemiology in the United States Prior to the Introduction of Vaccines

Respiratory syncytial virus (RSV) causes lower respiratory tract illness frequently. No effective antivirals or vaccines for RSV are approved for use in the United States; however, there are at least 50 vaccines and monoclonal antibody products in development, with those targeting older adults and pregnant women (to protect young infants) in phase 2 and 3 clinical trials. Unanswered questions regarding RSV epidemiology need to be identified and addressed prior to RSV vaccine introduction to guide the measurement of impact and future recommendations. The Centers for Disease Control and Prevention (CDC) convened a technical consultation to gather input from external subject matter experts on their individual perspectives regarding evidence gaps in current RSV epidemiology in the United States, potential studies and surveillance platforms needed to fill these gaps, and prioritizing efforts. Participants articulated their individual views, and CDC staff synthesized individuals' input into this report.

The global burden of respiratory infections in indigenous children and adults: A review

This review article focuses on common lower respiratory infections (LRIs) in indigenous populations in both developed and developing countries, where data is available. Indigenous populations across the world share some commonalities including poorer health and socio-economic disadvantage compared with their non-indigenous counterparts. Generally, acute and chronic respiratory infections are more frequent and more severe in both indigenous children and adults, often resulting in substantial consequences including higher rates of bronchiectasis and poorer outcomes for patients with chronic obstructive pulmonary disease (COPD). Risk factors for the development of respiratory infections require recognition and action. These risk factors include but are not limited to socio-economic factors (e.g. education, household crowding and nutrition), environmental factors (e.g. smoke exposure and poor access to health care) and biological factors. Risk mitigation strategies should be delivered in a culturally appropriate manner and targeted to educate both individuals and communities at risk. Improving the morbidity and mortality of respiratory infections in indigenous people requires provision of best practice care and awareness of the scope of the problem by healthcare practitioners, governing bodies and policy makers.

[A molecular epidemiological study of KI polyomavirus and WU polyomavirus in children with acute respiratory infection in Tianjin, China]

OBJECTIVE

To investigate the relationship of KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) with acute respiratory infection in children in Tianjin, China.

METHODS

A total of 3 730 nasopharyngeal secretions were collected from hospitalized children with acute respiratory infection in Tianjin Children's Hospital from January 2011 to December 2013. Viral nucleic acid was extracted, and virus infection (KIPyV and WUPyV) was determined by PCR. Some KIPyV-positive and WUPyV-positive PCR products were subjected to sequencing. Sequencing results were aligned with the known gene sequences of KIPyV and WUPyV to construct a phylogenetic tree. Amplified VP1 fragments of KIPyV were inserted into the cloning vector (PUCm-T) transformed into E. coli competent cells. Positive clones were identified by PCR and sequencing. The nucleotide sequences were submitted to GenBank. In addition, another seven common respiratory viruses in all samples were detected by direct immunofluorescence assay.

RESULTS

In the 3 730 specimens, the KIPyV-positive rate was 12.14% (453/3 730) and the WUPyV-positive rate was 1.69% (63/3 730). The mean infection rate of KIPyV was significantly higher in June and July, while the mean infection rate of WUPyV peaked in February and March. Most of the KIPyV-positive or WUPyV-positive children were <3 years. The co-infections with KIPyV, WUPyV, and other respiratory viruses were observed in the children. The co-infection rate was 2.31% (86/3 730) and there were nine cases of co-infections with WUPyV and KIPyV. Thirty-five KIPyV-positive and twelve WUPyV-positive PCR products were sequenced and the alignment analysis showed that they had high homology with the known sequences (94%-100% vs 95%-100%). The VP1 gene sequences obtained from two KIPyV strains in this study were recorded in GenBank with the accession numbers of KY465925 and KY465926.

CONCLUSIONS

For some children with acute respiratory infection in Tianjin, China, the acute respiratory infection may be associated with KIPyV and WUPyV infections. KIPyV infection is common in summer, and WUPyV infection in spring. The epidemic strains in Tianjin have a high homology with those in other regions.

Costs associated with infant bronchiolitis in the Baffin region of Nunavut

OBJECTIVE. Although infants living in the north of Canada have been reported to have one of the highest rates of hospital admission for bronchiolitis in the world, the economic effects of this condition have not been reported. Passive immunization against the Respiratory Syncytial Virus, the most common causative agent of infant bronchiolitis, is available.

METHODS

We tabulated transportation, in-hospital care and family accommodation costs for infants of less than 12 months of age residing in the Baffin Region of Nunavut aged who were admitted to Baffin Regional Hospital in Iqaluit, Nunavut, and the Children's Hospital of Eastern Ontario in Ottawa, Ontario, with a primary diagnosis of bronchiolitis or viral pneumonia, over a 36-month period, between April 1999 and March 2002.

RESULTS

One hundred fifty-nine infants were admitted a total of 210 times, with 196 admissions to Baffin Regional Hospital, and 14 to the Children's Hospital of Eastern Ontario, during the study period. The overall, annual, population-based admission rate for the Baffin Region of Nunavut was 197 admissions per thousand infants per year. Total costs were $2,997,373 ($2,357,747 for Baffin Regional Hospital, $639,625 for the Children's Hospital of Eastern Ontario). Overall average costs were $14,273 per admission, $12,029 for infants admitted to Baffin Regional Hospital and $45,688 for infants admitted to the Children's Hospital of Eastern Ontario.

CONCLUSIONS

Infant bronchiolitis in the Baffin Region of Nunavut represents a significant burden on the territorial health care system.

Impact of providing in-home water service on the rates of infectious diseases: results from four communities in Western Alaska

Approximately 20% of rural Alaskan homes lack in-home piped water; residents haul water to their homes. The limited quantity of water impacts the ability to meet basic hygiene needs. We assessed rates of infections impacted by water quality (waterborne, e.g. gastrointestinal infections) and quantity (water-washed, e.g. skin and respiratory infections) in communities transitioning to in-home piped water. Residents of four communities consented to a review of medical records 3 years before and after their community received piped water. We selected health encounters with ICD-9CM codes for respiratory, skin and gastrointestinal infections. We calculated annual illness episodes for each infection category after adjusting for age. We obtained 5,477 person-years of observation from 1032 individuals. There were 9,840 illness episodes with at least one ICD-9CM code of interest; 8,155 (83%) respiratory, 1,666 (17%) skin, 241 (2%) gastrointestinal. Water use increased from an average 1.5 gallons/capita/day (g/c/d) to 25.7 g/c/d. There were significant (P-value < 0.05) declines in respiratory (16, 95% confidence interval (CI): 11-21%), skin (20, 95%CI: 10-30%), and gastrointestinal infections (38, 95%CI: 13-55%). We demonstrated significant declines in respiratory, skin and gastrointestinal infections among individuals who received in-home piped water. This study reinforces the importance of adequate quantities of water for health.

Oxidative stress and inflamatory plasma biomarkers in respiratory syncytial virus bronchiolitis

INTRODUCTION

Oxidative stress (OS) plays a crucial role in the pathogenesis of inflammatory lung diseases.

OBJECTIVES

(i) We determined whether acute bronchiolitis (AB) caused by respiratory syncytial virus (RSV) induced OS; (ii) assessed whether OS biomarkers correlated with the severity of RSV-AB; and (iii) studied whether the levels of interleukins are associated with OS biomarkers.

METHODS

We performed an observational study by comparing healthy infants (Group 1) with RSV-AB infants, classified as Group 2 (pulse oximetry (SpO₂ ) >93%), and Group 3 (SpO₂  ≤ 92%), which needed oxygen therapy. Blood samples were collected to determine the levels of lipid peroxidation (LPO) products (LPO), total glutathione (TG), oxidised glutathione (GSSG), reduced glutathione (GSH), glutathione peroxidase (GPx), interleukins (ILs) IL-10, IL-6, IL-8, interferon-gamma (IFNγ), tumour necrosis factor-alpha (TNFα) and macrophage inflammatory proteins (MIP α and MIP β).

RESULTS

Forty-six RSV-AB infants (47% needed oxygen therapy) and 27 healthy infants were included. The GSH/GSSG ratio was lower in RSV-AB infants than in Group 1 (P<0.001). GSSG and GPx were significantly higher in Group 3. GSSG predicted the need for oxygen therapy with an optimal cut-off point of 15 µM/g for haemoglobin. The GSH/GSSG ratio negatively correlated with IL-6 (P: 0.014), IL-8 (P: 0.014) and IL-10 (P: 0.033). Group 3 exhibited a direct correlation between GPx and IL-10 levels (P: 0.024) and between LPO and MIP β (P: 0.003).

CONCLUSIONS

RSV induced OS in AB. An increase in GSSG correlated with the disease severity in the infants. OS may contribute to the pathogenesis of RSV-AB.

Lung disease in indigenous children

Children in indigenous populations have substantially higher respiratory morbidity than non-indigenous children. Indigenous children have more frequent respiratory infections that are, more severe and, associated with long-term sequelae. Post-infectious sequelae such as chronic suppurative lung disease and bronchiectasis are especially prevalent among indigenous groups and have lifelong impact on lung function. Also, although estimates of asthma prevalence among indigenous children are similar to non-indigenous groups the morbidity of asthma is higher in indigenous children. To reduce the morbidity of respiratory illness, best-practice medicine is essential in addition to improving socio-economic factors, (eg household crowding), tobacco smoke exposure, and access to health care and illness prevention programs that likely contribute to these issues. Although each indigenous group may have unique health beliefs and interfaces with modern health care, a culturally sensitive and community-based comprehensive care system of preventive and long term care can improve outcomes for all these conditions. This article focuses on common respiratory conditions encountered by indigenous children living in affluent countries where data is available.

Bronchiolitis and pneumonia requiring hospitalization in young first nations children in Northern Ontario, Canada

BACKGROUND

High rates of lower respiratory tract infection (LRTI), including bronchiolitis and pneumonia, have been reported in Inuit infants living in arctic Canada. We examined rates of LRTI in First Nations Canadian infants living in the Sioux Lookout Zone, in Northern Ontario.

METHODS

A retrospective review of hospital admissions for LRTI during a 5-year period, in patients <1 year of age was carried out at the Sioux Lookout Meno Ya Win Health Centre, an acute-care hospital that provides secondary care to 31 mainly isolated communities and the town of Sioux Lookout. Admission rates were compared with those in the province of Ontario, as a whole.

RESULTS

One-hundred and seventeen subjects were identified. The annualized rate of admission for nonbacterial LRTI was 44 per 1000 infants <1 year of age per year. This rate was significantly higher than for the whole province (P = 0.011). Admission rates also varied significantly between communities (P < 0.001).Thirteen percent of subjects required transfer to a tertiary care center. A virus was identified in 55% (36/65) of subjects tested for respiratory viruses, and respiratory syncytial virus and parainfluenza virus were identified most often. Of patients who had a blood culture performed, bacteria were found in 10% (6/59) of subjects. Many patients had radiographic evidence of consolidation, consistent with pneumonia.

CONCLUSIONS

Rates of LRTI are significantly elevated in First Nations infants living in the Sioux Lookout Zone. Varying rates between communities suggest that environmental factors may be contributing to rates of LRTI in this population.

Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection

Guidance from the American Academy of Pediatrics (AAP) for the use of palivizumab prophylaxis against respiratory syncytial virus (RSV) was first published in a policy statement in 1998. Guidance initially was based on the result from a single randomized, placebo-controlled clinical trial conducted in 1996-1997 describing an overall reduction in RSV hospitalization rate from 10.6% among placebo recipients to 4.8% among children who received prophylaxis. The results of a second randomized, placebo-controlled trial of children with hemodynamically significant heart disease were published in 2003 and revealed a reduction in RSV hospitalization rate from 9.7% in control subjects to 5.3% among prophylaxis recipients. Because no additional controlled trials regarding efficacy were published, AAP guidance has been updated periodically to reflect the most recent literature regarding children at greatest risk of severe disease. Since the last update in 2012, new data have become available regarding the seasonality of RSV circulation, palivizumab pharmacokinetics, the changing incidence of bronchiolitis hospitalizations, the effects of gestational age and other risk factors on RSV hospitalization rates, the mortality of children hospitalized with RSV infection, and the effect of prophylaxis on wheezing and palivizumab-resistant RSV isolates. These data enable further refinement of AAP guidance to most clearly focus on those children at greatest risk.

Household reporting of childhood respiratory health and air pollution in rural Alaska Native communities

Background

Air pollution is an important contributor to respiratory disease in children.

Objective

To examine associations between household reporting of childhood respiratory conditions and household characteristics related to air pollution in Alaska Native communities.

Design

In-home surveys were administered in 2 rural regions of Alaska. The 12-month prevalence of respiratory conditions was summarized by region and age. Odds ratios (ORs) were calculated to describe associations between respiratory health and household and air quality characteristics.

Results

Household-reported respiratory health data were collected for 561 children in 328 households. In 1 region, 33.6% of children aged <5 years had a recent history of pneumonia and/or bronchitis. Children with these conditions were 2 times more likely to live in a wood-heated home, but these findings were imprecise. Resident concern with mould was associated with elevated prevalence of respiratory infections in children (ORs 1.6–2.5), while reported wheezing was associated with 1 or more smokers living in the household. Reported asthma in 1 region (7.6%) was lower than national prevalence estimates.

Conclusions

Findings suggest that there may be preventable exposures, including wood smoke and mould that affect childhood respiratory disease in these rural areas. Additional research is needed to quantify particulate matter 2.5 microns in aerodynamic diameter or less and mould exposures in these communities, and to objectively evaluate childhood respiratory health.

Increasing trend in the rate of infectious disease hospitalisations among Alaska Native people

OBJECTIVES

To examine the epidemiology of infectious disease (ID) hospitalisations among Alaska Native (AN) people.

METHODS

Hospitalisations with a first-listed ID diagnosis for American Indians and ANs residing in Alaska during 2001-2009 were selected from the Indian Health Service direct and contract health service inpatient data. ID hospitalisations to describe the general US population were selected from the Nationwide Inpatient Sample. Annual and average annual (2007-2009) hospitalization rates were calculated.

RESULTS

During 2007-2009, IDs accounted for 20% of hospitalisations among AN people. The 2007-2009 average annual age-adjusted ID hospitalisation rate (2126/100,000 persons) was higher than that for the general US population (1679/100,000; 95% CI 1639-1720). The ID hospitalisation rate for AN people increased from 2001 to 2009 (17%, p < 0.001). Although the rate during 2001-2009 declined for AN infants (< 1 year of age; p = 0.03), they had the highest 2007-2009 average annual rate (15106/100,000), which was 3 times the rate for general US infants (5215/100,000; 95% CI 4783-5647). The annual rates for the age groups 1-4, 5-19, 40-49, 50-59 and 70-79 years increased (p < 0.05). The highest 2007-2009 age-adjusted average annual ID hospitalisation rates were in the Yukon-Kuskokwim (YK) (3492/100,000) and Kotzebue (3433/100,000) regions; infant rates were 30422/100,000 and 26698/100,000 in these regions, respectively. During 2007-2009, lower respiratory tract infections accounted for 39% of all ID hospitalisations and approximately 50% of ID hospitalisations in YK, Kotzebue and Norton Sound, and 74% of infant ID hospitalisations.

CONCLUSIONS

The ID hospitalisation rate increased for AN people overall. The rate for AN people remained higher than that for the general US population, particularly in infants and in the YK and Kotzebue regions. Prevention measures to reduce ID morbidity among AN people should be increased in high-risk regions and for diseases with high hospitalisation rates.

Respiratory health outcomes 1 year after admission with severe lower respiratory tract infection

Severe lower respiratory infection (LRI) is believed to be one precursor of protracted bacterial bronchitis, chronic moist cough (CMC), and chronic suppurative lung disease. The aim of this study was to determine and to describe the presence of respiratory morbidity in young children 1 year after being hospitalized with a severe LRI. Children aged less than 2 years admitted from August 1, 2007 to December 23, 2007 already enrolled in a prospective epidemiology study (n = 394) were included in this second study only if they had a diagnosis of severe bronchiolitis or of pneumonia with no co-morbidities (n = 237). Funding allowed 164 to be identified chronologically, 131 were able to be contacted, and 94 agreed to be assessed by a paediatrician 1 year post index admission. Demographic information, medical history and a respiratory questionnaire was recorded, examination, pulse oximetry, and chest X-ray (CXR) were performed. The predetermined primary endpoints were; (i) history of CMC for at least 3 months, (ii) the presence of moist cough and/or crackles on examination in clinic, and (iii) an abnormal CXR when seen at a time of stability. Each CXR was read by two pediatric radiologists blind to the individuals' current health. Results showed 30% had a history of CMC, 32% had a moist cough and/or crackles on examination in clinic, and in 62% of those with a CXR it was abnormal. Of the 81 children with a readable follow-up X-ray, 11% had all three abnormal outcomes, and 74% had one or more abnormal outcomes. Three children had developed bronchiectasis on HRCT. The majority of children with a hospital admission at <2 years of age for severe bronchiolitis or pneumonia continued to have respiratory morbidity 1 year later when seen at a time of stability, with a small number already having sustained significant lung disease.

A randomized double-blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 μg/m(3) , 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217-ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9-mm Hg (95% CI: -17, 0.82) decrease in systolic blood pressure, and a 4.5-mm Hg (95% CI: -11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities.

PRACTICAL IMPLICATIONS

Indoor air quality is known to contribute to adverse cardiorespiratory health, but few studies have examined indoor air quality in First Nations communities. Our findings suggest that indoor PM2.5 may contribute to reduced lung function and that portable air filters may help to alleviate these effects by effectively reducing indoor levels of particulate matter.

Global and regional burden of hospital admissions for severe acute lower respiratory infections in young children in 2010: a systematic analysis

BACKGROUND

The annual number of hospital admissions and in-hospital deaths due to severe acute lower respiratory infections (ALRI) in young children worldwide is unknown. We aimed to estimate the incidence of admissions and deaths for such infections in children younger than 5 years in 2010.

METHODS

We estimated the incidence of admissions for severe and very severe ALRI in children younger than 5 years, stratified by age and region, with data from a systematic review of studies published between Jan 1, 1990, and March 31, 2012, and from 28 unpublished population-based studies. We applied these incidence estimates to population estimates for 2010, to calculate the global and regional burden in children admitted with severe ALRI in that year. We estimated in-hospital mortality due to severe and very severe ALRI by combining incidence estimates with case fatality ratios from hospital-based studies.

FINDINGS

We identified 89 eligible studies and estimated that in 2010, 11·9 million (95% CI 10·3-13·9 million) episodes of severe and 3·0 million (2·1-4·2 million) episodes of very severe ALRI resulted in hospital admissions in young children worldwide. Incidence was higher in boys than in girls, the sex disparity being greatest in South Asian studies. On the basis of data from 37 hospital studies reporting case fatality ratios for severe ALRI, we estimated that roughly 265,000 (95% CI 160,000-450,000) in-hospital deaths took place in young children, with 99% of these deaths in developing countries. Therefore, the data suggest that although 62% of children with severe ALRI are treated in hospitals, 81% of deaths happen outside hospitals.

INTERPRETATION

Severe ALRI is a substantial burden on health services worldwide and a major cause of hospital referral and admission in young children. Improved hospital access and reduced inequities, such as those related to sex and rural status, could substantially decrease mortality related to such infection. Community-based management of severe disease could be an important complementary strategy to reduce pneumonia mortality and health inequities.

FUNDING

WHO.

Human genetics and respiratory syncytial virus disease: current findings and future approaches

Infection with respiratory syncytial virus (RSV) can result in a wide spectrum of pulmonary manifestations, from mild upper respiratory symptoms to severe bronchiolitis and pneumonia. Although there are several known risk factors for severe RSV disease, namely, premature birth, chronic lung disease, congenital heart disease, and T cell immunodeficiency, the majority of young children who develop severe RSV disease are otherwise healthy children. Genetic susceptibility to RSV infection is emerging as a complex trait, in which many different host genetic variants contribute to risk for distinct disease manifestations. Initially, host genetic studies focused on severe RSV disease using the candidate gene approach to interrogate common single nucleotide polymorphisms (SNPs). Many studies have reported genetic associations between severe RSV bronchiolitis and SNPs in genes within plausible biological pathways, such as in innate host defense genes (SPA, SPD, TLR4, and VDR), cytokine or chemokine response genes (CCR5, IFN, IL6, IL10, TGFB1), and altered Th1/Th2 immune responses (IL4, IL13). Due to the complexity of RSV susceptibility, genome studies done on a larger scale, such as genome-wide association studies have certainly identified more of the host factors that contribute to the development of severe RSV bronchiolitis or excessive pathology. Furthermore, whole-genome approaches can reveal robust associations between genetic markers and RSV disease susceptibility. Recent introduction of 'exome' genotyping or sequencing, which specifically analyzes the majority of coding variants, should be fruitful in sufficiently large, well-powered studies. The advent of new genomic technologies together with improved computational tools offer the promise of interrogating the host genome in search of genetic factors, rare, uncommon, or common that should give new insights into the underlying biology of susceptibility to or protection from severe RSV infection. Careful assessment of novel pathways and further identification of specific genes could identify new approaches for vaccine development and perhaps lead to effective risk modeling.

[Epidemiology, clinical features and medical interventions in children hospitalized for bronchiolitis]

OBJECTIVES

To describe the epidemiology, clinical characteristics and treatments prescribed in children with bronchiolitis admitted to our hospital.

MATERIAL AND METHODS

Observational, descriptive and prospective study of children younger than 18 months, admitted to Hospital Virgen de la Arrixaca of Murcia (Spain), with the diagnosis of bronchiolitis, during the season of maximum incidence (December 2008-April 2009).

RESULTS

A total of 235 infants were admitted, of whom 78.7% of them were aged 5 months or less. We found a positive correlation between the number of cigarettes smoked by their mothers during pregnancy and the number of hospitalization and oxygen therapy days. Children whose mothers were smokers at the time of their admission needed a greater number of oxygen therapy days. Also infants who were not breastfed needed oxygen therapy during more days. Just under one quarter (23.8%) of them had underlying diseases, with prematurity being the most frequent and a risk factor for the ongoing of oxygen therapy and hospital stay. The use of diagnostic tests, bronchodilators, corticosteroids and antibiotics was high. The onset of high temperature was associated with an increased use of antibiotics in outside and inside the hospital setting. An abnormal chest X-ray or a raised C-reactive protein was associated with a higher use of antibiotics. Respiratory Syncytial virus (RSV) was the main aetiological agent, followed by Rhinovirus, Bocavirus, Adenovirus and Metapneumovirus

CONCLUSIONS

The majority of hospital admissions due to bronchiolitis took place during the first months of life. Infants whose mothers smoked during pregnancy had a worse clinical outcome. Despite the availability of clinical practice guidelines in our area, the use of diagnostic tests and pharmacological treatment was high.

Trends in lower respiratory tract infection hospitalizations among American Indian/Alaska Native children and the general US child population

OBJECTIVE

To describe trends in the rate of hospitalization for lower respiratory tract infection (LRTI) among American Indian/Alaska Native (AI/AN) children and the general US population of children aged <5 years.

STUDY DESIGN

This was a retrospective analysis of trends and hospitalization rates for LRTI-associated hospitalizations in 1998-2008 among AI/AN children aged <5 years using the Indian Health Service direct/contract inpatient data, and also among the general population of US children aged <5 years using the Nationwide Inpatient Sample.

RESULTS

The 2006-2008 LRTI-associated hospitalization rate for AI/AN children aged <5 years (21.8 per 1000/year) was 32% lower than the 1998-1999 rate, and 1.6-fold higher than the general US children rate (13.8 per 1000/year; 95% CI, 12.8-14.8). Higher rates were seen in AI/AN children aged <5 years in the Alaska and the Southwest regions of the United States (41.2 and 28.0 per 1000/year, respectively). In infants, these rates were 136.4 and 82.4 per 1000/year, respectively, exceeding the rate in the general US infant population (37.1 per 1000/year; 95% CI, 34.3-40.0). The greatest disparity in the LRTI-associated hospitalization rate between AI/AN infants and the general US infant population was seen for pneumonia, with a 3-fold higher rate in AI/AN infants (36.2 per 1000/year vs 12.7 per 1000/year; 95% CI, 11.8-13.6).

CONCLUSION

The LRTI-associated hospitalization rate is higher in AI/AN children, particularly infants from Alaska and the American Southwest, compared with the general US child population. Closing this gap will require addressing housing and sanitation inequities and ensuring high immunization rates and access to care.

Pathogenesis of respiratory syncytial virus

While affecting all age groups, respiratory syncytial virus (RSV) infections can be particularly severe in infants, who develop functionally distinct immune responses, as well as in immunocompromised individuals. The extent to which environmental, viral and host factors contribute to the pathogenesis of RSV varies considerably between infected individuals. A correlation between the level of virus replication and pathogenesis has been established, and several viral proteins, in particular NS1 and NS2, modulate the immune response. Host immunity clearly contributes to RSV pathogenesis, and a number of specific cell populations may be involved. Ultimately, whether the response induced by RSV is protective or pathogenic depends on a combination of host factors, young age being one of the most important ones.

WU polyomavirus infection among children in South China

This study aimed at investigating the prevalence and clinical characteristics of children with respiratory infection by WU polyomavirus (WUPyV) in Southern China. Nasopharyngeal aspirate samples were collected from 771 children with acute respiratory tract infection admitted to hospital and 82 samples from healthy subjects for routine examination at the outpatient service at the Second Affiliated Hospital of Shantou University, Medical College from July 2008 to June 2009. WUPyV was detected by the polymerase chain reaction (PCR) and DNA sequencing. All WUPyV-positive specimens were characterized further for nine viruses causing common respiratory infections, including influenza A and B, respiratory syncytial virus (RSV), parainfluenza virus (PIV) 1 and 3, human metapneumovirus, human bocavirus, adenovirus, and rhinovirus by PCR or real time (RT)-PCR. Fifteen out of 771 specimens from patients with acute respiratory tract infection, but none from healthy subjects, were positive for WUPyV and the positivity rate was 2%. Patients with WUPyV infection were between 2 and 48 months of age, and nine of the patients were male while six female. Four out of 15 patients were co-infected with RSV, one with adenovirus or rhinovirus, respectively. Patients with WUPyV infection displayed predominantly cough, moderate fever, and wheezing, and were diagnosed with pneumonia (n = 8), bronchiolitis (n = 4), upper respiratory tract infections (n = 2) and bronchitis (n = 1). One patient developed encephalitis. Therefore, WUPyV infection can cause acute respiratory tract infection with atypical symptoms, including severe complications, in children.

A decade of respiratory syncytial virus epidemiology and prophylaxis: translating evidence into everyday clinical practice

Respiratory syncytial virus (RSV) is a common infection in infancy, with nearly all children affected by two years of age. Approximately 0.5% to 2.0% of all children are hospitalized with lower respiratory tract disease, of which 50% to 90% have bronchiolitis and 5% to 40% have pneumonia. Morbidity and mortality are highest in children with nosocomial infection and in those with underlying medical illnesses such as cardiac and chronic lung disease. Aboriginal children residing in remote northern regions are specifically considered to be at high risk for hospitalization due to RSV infection. Thorough hand washing and health education are the principal strategies in primary prevention. In the absence of a vaccine, palivizumab prophylaxis is currently the best intervention to reduce the burden of illness and RSV-related hospitalization in high-risk children. Health care professionals should provide palivizumab prophylaxis cost effectively in accordance with recommendations issued by pediatric societies and national advisory bodies. The present article reviews the epidemiology of RSV infection and the short- and long-term impact of disease in high-risk infants and special populations. Prevention strategies and treatment are discussed based on the existing scientific evidence, and future challenges in the management of RSV infection are addressed.

Presentations of infants to emergency departments in Alberta, Canada, for bronchiolitis: a large population-based study

OBJECTIVES

Bronchiolitis is the most common lower respiratory tract disease among infants and results in 35 admissions per 1000 infants in Canada. We describe the epidemiology of bronchiolitis presentations to emergency departments (EDs) made by infants (aged ≤2 years) in Alberta, Canada.

METHODS

Provincial administrative databases were used to obtain all ED encounters for bronchiolitis during April 1999 to March 2005. Information included demographics, ED visit timing, and subsequent visits to non-ED settings. Data analysis included summaries and standardized rates.

RESULTS

There were 26,742 ED visits for bronchiolitis made by 18,155 infants. Most (74.9%) had only 1 bronchiolitis-related ED visit; males (60.6% of ED visits, 59.8% of infants) more commonly presented than females. The standardized rates increased from 23.2 to 46.7 per 1000 in 1999/2000 to 2000/2001 and decreased gradually to 38.8 per 1000 in 2004/2005. Of the total visits, 22.6% required hospitalization. In a discharged subset, 10.4% had a repeat ED visit within 7 days. Most infants (63.3%) had yet to have a non-ED follow-up visit by 1 week; median time to the first follow-up was 18 days.

CONCLUSIONS

Bronchiolitis is a common presenting problem in Alberta EDs, and further study of these trends is required to understand variation in presentations. The important findings include different trends in rates for the first 3 years before a gradual decrease, disparities based on age, sex, and socioeconomic/cultural status, and the low rate of early follow-up. Targeted interventions could be implemented to reduce bronchiolitis-related hospitalizations.

Maternal influenza vaccination and effect on influenza virus infection in young infants

OBJECTIVE

To assess the effect of seasonal influenza vaccination during pregnancy on laboratory-confirmed influenza in infants to 6 months of age.

DESIGN

Nonrandomized, prospective, observational cohort study.

SETTING

Navajo and White Mountain Apache Indian reservations, including 6 hospitals on the Navajo reservation and 1 on the White Mountain Apache reservation.

PARTICIPANTS

A total of 1169 mother-infant pairs with mothers who delivered an infant during 1 of 3 influenza seasons.

MAIN EXPOSURE

Maternal seasonal influenza vaccination.

MAIN OUTCOME MEASURES

In infants, laboratory-confirmed influenza, influenza-like illness (ILI), ILI hospitalization, and influenza hemagglutinin inhibition antibody titers.

RESULTS

A total of 1160 mother-infant pairs had serum collected and were included in the analysis. Among infants, 193 (17%) had an ILI hospitalization, 412 (36%) had only an ILI outpatient visit, and 555 (48%) had no ILI episodes. The ILI incidence rate was 7.2 and 6.7 per 1000 person-days for infants born to unvaccinated and vaccinated women, respectively. There was a 41% reduction in the risk of laboratory-confirmed influenza virus infection (relative risk, 0.59; 95% confidence interval, 0.37-0.93) and a 39% reduction in the risk of ILI hospitalization (relative risk, 0.61; 95% confidence interval, 0.45-0.84) for infants born to influenza-vaccinated women compared with infants born to unvaccinated mothers. Infants born to influenza-vaccinated women had significantly higher hemagglutinin inhibition antibody titers at birth and at 2 to 3 months of age than infants of unvaccinated mothers for all 8 influenza virus strains investigated.

CONCLUSIONS

Maternal influenza vaccination was significantly associated with reduced risk of influenza virus infection and hospitalization for an ILI up to 6 months of age and increased influenza antibody titers in infants through 2 to 3 months of age.

Lower respiratory infections in Australian Indigenous children

Despite Australia being one of the wealthiest countries of the world, Australian Indigenous children have a health status and social circumstance comparable to developing countries. Indigenous infants have 10 times the mortality rate for respiratory conditions. The lower respiratory infection (LRI) rate in Australian Indigenous children is at least as high as that of children in developing countries; the frequency of hospitalisations of Indigenous infants is triple that of non-Indigenous Australian infants (201.7 vs. 62.6/1000, respectively). While Indigenous Australian children have many risk factors for LRIs described in developing countries, there is little specific data, and hence, evidence-based intervention points are yet to be identified. Efficacy of conjugate vaccines for common bacterial causes of pneumonia has been less marked in Indigenous children than that documented overseas. Gaps in the management and prevention of disease are glaring. Given the burden of LRI in Indigenous children and the association with long-term respiratory dysfunction, LRIs should be addressed as a matter of priority.

Navajo coal combustion and respiratory health near Shiprock, New Mexico

Indoor air pollution has been identified as a major risk factor for acute and chronic respiratory diseases throughout the world. In the sovereign Navajo Nation, an American Indian reservation located in the Four Corners area of the USA, people burn coal in their homes for heat. To explore whether/how indoor coal combustion might contribute to poor respiratory health of residents, this study examined respiratory health data, identified household risk factors such as fuel and stove type and use, analyzed samples of locally used coal, and measured and characterized fine particulate airborne matter inside selected homes. In twenty-five percent of homes surveyed coal was burned in stoves not designed for that fuel, and indoor air quality was frequently found to be of a level to raise concerns. The average winter 24-hour PM_2.5 concentration in 20 homes was 36.0 μg/m³. This is the first time that PM_2.5 has been quantified and characterized inside Navajo reservation residents' homes.

Lower respiratory tract infections

Acute lower respiratory infections (ALRI) are the major cause of morbidity and mortality in young children worldwide. ALRIs are important indicators of the health disparities that persist between Indigenous and non-Indigenous children in developed countries. Bronchiolitis and pneumonia account for the majority of the ALRI burden. The epidemiology, diagnosis, and management of these diseases in Indigenous children are discussed. In comparison with non-Indigenous children in developing countries they have higher rates of disease, more complications, and their management is influenced by several unique factors including the epidemiology of disease and, in some remote regions, constraints on hospital referral and access to highly trained staff. The prevention of repeat infections and the early detection and management of chronic lung disease is critical to the long-term respiratory and overall health of these children.

Nutritional rickets and vitamin D deficiency--association with the outcomes of childhood very severe pneumonia: a prospective cohort study

BACKGROUND

The association of rickets and vitamin D deficiency (VDD) with pneumonia is well documented, but not with its outcomes.

OBJECTIVES

To investigate whether rickets and VDD predict the outcomes in very severe pneumonia (VSP).

DESIGN

A prospective cohort study conducted at Al-Sabeen hospital in Sana'a, Yemen. A total of 152 children aged 2-59 months with WHO-defined VSP were enrolled, managed, and followed for up to 30 days. Treatment outcome was either successful or failure (antibiotic modification for clinical worsening, death, relapse after 10-day antibiotics, or development of complications). Serum vitamin D (25OHD) was measured in 79 cases. A concentration of <or=30 nmol/L defines VDD.

MAIN OUTCOME MEASURES

Association of rickets with treatment outcome; and VDD with the circulating neutrophils (PMNs), and oxygen saturation% (SpO(2)%), respectively.

RESULTS

Treatment failure occurred in 24 (15.8%), all aged 2-12 months, and 21 (87.5%) were rachitic. Of the 79 subset, 29 had VDD of which 23 (79.3%) had rickets. Treatment failure was significantly higher in the rachitic compared to non-rachitic [20.6% (21/102) vs. 6% (3/50); OR 1.38 (95% CI 1.13-1.69), P = 0.031]. In multivariate regression, rickets significantly predict a reduced successful treatment compared with non-rachitic [79.4% (81/102) vs. 94% (47/50); Adjusted OR 0.41 (95% CI 0.20-0.85); P = 0.02]. VDD was strongly associated with reduced PMNs% [Mean (SD) 37 (17) vs. 47 (17); Adjusted OR 0.71 (95% CI 0.53-0.95), P = 0.02], and reduced SpO(2)% [Mean (SD) 85.9 (7.9) vs. 89.8 (7.1); OR 0.96 (95% CI 0.93-0.99), P = 0.021].

CONCLUSIONS

In VSP, rickets was significantly associated with treatment outcome and VDD significantly predict both reduced circulating PMNs, and Day-5 hypoxemia (SpO(2)%, <88%).

Burden of infant bronchiolitis: data from a hospital network

In France, surveillance of bronchiolitis is based on a pilot network of hospital emergency departments. The study was a 1-year observational study (2007-2008) carried out in a central region of metropolitan France. The hospitalization rate for bronchiolitis was 17.7/1000 children aged <1 year and the estimated prevalence of bronchiolitis ranged from 17.7% to 34.4% in children aged <1 year. Such a network constitutes a valuable tool to estimate the dynamic and the burden of infant bronchiolitis.

Risk factors for lower respiratory tract infection death among infants in the United States, 1999-2004

OBJECTIVE

To describe maternal and birth-related risk factors associated with lower respiratory tract infection (LRTI) deaths among infants.

METHODS

Records for infants with LRTI as a cause of death were examined by using the linked birth/infant death database for 1999-2004. Singleton infants dying with LRTI and a random sample of surviving singleton infants were compared for selected characteristics.

RESULTS

A total of 5420 LRTI-associated infant deaths were documented in the United States during 1999-2004, for an LRTI-associated infant mortality rate of 22.3 per 100,000 live births. Rates varied according to race; the rate for American Indian/Alaska Native (AI/AN) infants was highest (53.2), followed by black (44.1), white (18.7), and Asian/Pacific Islander infants (12.3). Singleton infants with low birth weight (<2500 g) were at increased risk of dying with LRTI after controlling for other characteristics, especially black infants. Both AI/AN and black infants born with a birth weight of > or =2500 g were more likely to have died with LRTI than other infants of the same birth weight. Other risk factors associated with LRTI infant death included male gender, the third or more live birth, an Apgar score of <8, unmarried mother, mother with <12 years of education, mother <25 years of age, and mother using tobacco during pregnancy.

CONCLUSIONS

Low birth weight was associated with markedly increased risk for LRTI-associated death among all of the racial groups. Among infants with a birth weight of > or =2500 g, AI/AN and black infants were at higher risk of LRTI-associated death, even after controlling for maternal and birth-related factors. Additional studies and strategies should focus on the prevention of maternal and birth-related risk factors for postneonatal LRTI and on identifying additional risk factors that contribute to elevated mortality among AI/AN and black infants.

Risk factors and viruses associated with hospitalization due to lower respiratory tract infections in Canadian Inuit children : a case-control study

OBJECTIVES

To examine risk factors for lower respiratory tract infections (LRTI) hospital admission in the Canadian Arctic.

METHODS

This was a case-control study during a 14-month period among children less than 2 years of age. Cases were admitted to the Baffin Regional Hospital in Iqaluit, Nunavut with LRTI. Controls were age matched and came from Iqaluit and 2 communities. Odds ratios (ORs) of hospital admission for LRTI were estimated through multivariate conditional logistic regression modeling for following risk factors: smoking in pregnancy, Inuit race, prematurity, adoption status, breast-feeding, overcrowding, and residing outside of Iqaluit. Viruses in nasophayngeal aspirates were sought at the time of each hospital admission.

RESULTS

There were 101 age-matched cases and controls. The following risk factors were significantly associated with an increased risk of admission for LRTI (adjusted OR): smoking in pregnancy (OR = 4.0; 95% CI: 1.1-14.6), residence outside of Iqaluit (OR = 2.7; 95% CI: 1.0 -7.2), full Inuit race (OR = 3.8; 95% CI: 1.1-12.8), and overcrowding (OR = 2.5, 95% CI: 1.1- 6.1). Non-breast-fed children had a 3.6-fold risk of being admitted for LRTI (95% CI: 1.2-11.5) and non-breast-fed adopted children had a 4.4-fold increased risk (95% CI: 1.1-17.6) when compared with breast-fed, nonadopted children. Prematurity was not associated with an increased risk of admission. Viruses were identified in 88 (72.7%) of admissions, with respiratory syncytial virus being identified in the majority of admissions, 62 (51.2%). Multiple viruses were isolated in 19 (15.7%) admissions.

CONCLUSIONS

Smoking during pregnancy, place of residence, Inuit race, lack of breast-feeding, and overcrowding were all independently associated with increased risk of hospital admission for LRTI among Inuit children less than 2 years of age. Future research on the role of adoption and genetics on the health of Inuit children are required.

Trends in otitis media and myringtomy with tube placement among American Indian/Alaska native children and the US general population of children

BACKGROUND

Otitis media (OM) morbidity in American Indian and Alaska Native (AI/AN) children is historically higher than that in other US children.

METHODS

Outpatient visits and hospitalizations listing OM as a diagnosis and outpatient visits listing myringotomy with insertion of tubes as a procedure among AI/AN children <5 years of age from the Indian Health Service National Patient Information Reporting system for 2003-2005 were analyzed. Outpatient visits and hospitalizations with OM for the general US child population were analyzed using the National Hospital Ambulatory Medical Care and National Ambulatory Medical Care Surveys for 2003-2005, and the 2003 Kids' Inpatient Database, respectively.

RESULTS

The OM-associated outpatient visit rate for AI/AN children <5 years of age (89 per 100 children/yr) for 2003-2005 was less than that reported for 1994-1996 (138); however, the rate increased for Alaska region (158 to 181). The OM outpatient visit and myringotomy with insertion of tubes rates (181 and 2.6 per 100 children/yr, respectively) for AI/AN children in Alaska were higher than rates for children in each of the other IHS regions and rates for US children (63 and 1.8 per 100 children/yr, respectively). The OM outpatient visit rates for AI/AN infants (184), especially in the Alaska region (334), were higher than the rate for US infants (84).

CONCLUSIONS

The OM-associated outpatient visit rate in AI/AN children <5 years of age has decreased but remains higher than that of the US general child population; however, the rate increased in the Alaska region, where a limited decline in invasive pneumococcal disease has been demonstrated. The ongoing disparity in OM outpatient visit rates among AI/AN children, especially Alaska Native children, indicates a need for new prevention measures, including expanded-valency pneumococcal conjugate vaccines, to reduce OM morbidity.

Innovative approaches in public health research: applying life course epidemiology to aboriginal health research

A life course epidemiology approach embraces the complexity of disease risk and acknowledges the long-term effects of physical, social, psychological, and behaviour pathways, operating across an individual's life, a community's generation, and a population's development, on health and well-being. Researchers who adopt a life course epidemiology approach broaden their ability to understand, explain, and prescribe ways to mitigate the effects of chronic diseases and reduce risk factor development and interaction. Although there are many diseases that explicate the importance and usefulness of a life course approach for Aboriginal health research, this commentary focuses on the benefits for understanding chronic respiratory diseases in Aboriginal populations. The hope is that this will expose the benefits of a life course approach for the study of Aboriginal health research and draw attention to the need for well-rounded, high-quality Aboriginal respiratory health research.

Descriptive epidemiological features of bronchiolitis in a population-based cohort

OBJECTIVE

The goal was to investigate the epidemiological features of incident bronchiolitis by using a population-based infant cohort.

METHODS

Outpatient and inpatient health records were used to identify incident bronchiolitis cases among 93,058 singleton infants born in the Georgia Air Basin between 1999 and 2002. Additional health-related databases were linked to provide data on sociodemographic variables, maternal characteristics, and birth outcome measures.

RESULTS

From 1999 to 2002, bronchiolitis accounted for 12,474 incident health care encounters (inpatient or outpatient contacts) during the first year of life (134.2 cases per 1000 person-years). A total of 1588 hospitalized bronchiolitis cases were identified (17.1 cases per 1000 person-years). Adjusted Cox proportional-hazard analyses for both case definitions indicated an increased risk of incident bronchiolitis in the first year of life (follow-up period: 2-12 months) for boys, infants of First Nations status, infants with older siblings, and infants living in neighborhoods with smaller proportions of maternal postsecondary education. The risk also was elevated for infants born to young mothers (<20 years of age) or mothers who did not initiate breastfeeding in the hospital. Infants with low (1500-2400 g) or very low (<1500 g) birth weight and those with congenital anomalies also had increased risk. Maternal smoking during pregnancy increased the risk of hospitalized bronchiolitis.

CONCLUSIONS

This population-based study of the epidemiological features of bronchiolitis provides evidence for intervening with high-risk infants and their families. Clinical and public health interventions are recommended for the modifiable risk factors of maternal breastfeeding and smoking and for modification of vulnerable environments where possible (eg, limiting exposure to other young children), during high-risk periods such as the first few months of life or the winter season.

Young infants can develop protective levels of neutralizing antibody after infection with respiratory syncytial virus

Humoral immunity protects against severe respiratory syncytial virus (RSV) disease, but the range and magnitude of antibody responses in RSV-naive children after RSV infection have not been completely defined. We evaluated RSV-neutralizing antibody and immunoglobulin G responses to RSV F and G glycoproteins in 65 RSV-naive Navajo and White Mountain Apache children aged 0-24 months who were hospitalized with RSV infection. In these children, antibody responses developed against RSV F and G and the central conserved region of RSV G. Twenty-seven of 41 infants <6 months old developed reciprocal log(2) RSV neutralizing antibody titers > or =8.0, which correlate with protection of the lower respiratory tract. Multivariate analysis demonstrated that the level of preexisting neutralizing antibody at infection, not age, was the most important factor influencing this response. RSV can induce substantial neutralizing antibody responses in young infants when the titer of preexisting antibodies is low.

Influenza A and respiratory syncytial virus hospital burden in young children in East London

Epidemiological studies have demonstrated high hospitalization rates attributable to influenza and RSV in children aged 6 months and those aged <12 months, respectively (43 and 92.5/10 000 person-months, respectively). In conclusion, these high paediatric RSV and influenza incidence rates can be used to inform UK policy on childhood influenza immunization and subsequent RSV immunization in the future.

Comparison of nebulized epinephrine to albuterol in bronchiolitis

OBJECTIVES

To compare the effect of nebulized racemic epinephrine to nebulized racemic albuterol on successful discharge from the emergency department (ED).

METHODS

Children up to their 18th month of life presenting to two teaching hospital EDs with a clinical diagnosis of bronchiolitis who were ill enough to warrant treatment but did not need immediate intubation were eligible for this double-blind randomized controlled trial (RCT). Patients received either three doses of racemic albuterol or one dose of racemic epinephrine plus two saline nebulizers. Disposition was decided 2 hours after the first nebulizer. Successful discharge was defined as not requiring additional bronchodilators in the ED after study drug administration and not subsequently admitted within 72 hours. Adjusted relative risks (aRR) were estimated using the modified Poisson regression with successful discharge as the dependent variable and study drug and severity of illness as exposures. Secondary analysis was performed for patients aged less than 12 months and first presentation.

RESULTS

The authors analyzed 703 patients; 352 patients were given albuterol and 351 epinephrine. A total of 173 in the albuterol group and 160 in the epinephrine group were successfully discharged (crude RR = 1.08, 95% confidence interval [CI] = 0.92 to 1.26). When adjusted for severity of illness, patients who received albuterol were significantly more likely than patients receiving epinephrine to be successfully discharged (aRR = 1.18, 95% CI = 1.02 to 1.36). This was also true among those with first presentation and in those less than 12 months of age.

CONCLUSIONS

In children up to the 18th month of life, ED treatment of bronchiolitis with nebulized racemic albuterol led to more successful discharges than nebulized epinephrine.

The role of neutralizing antibodies in protection of American Indian infants against respiratory syncytial virus disease

BACKGROUND

Navajo and White Mountain Apache infants have respiratory syncytial virus (RSV) hospitalization rates 2-5 times that of the general U.S. infant population. To evaluate whether these high rates can be attributable to low concentrations of maternally derived RSV neutralizing antibodies, we conducted a case-control study.

METHODS

Study subjects enrolled in a prospective, hospital-based surveillance study of RSV disease and a group randomized clinical trial of a 7-valent pneumococcal conjugate vaccine. Cord blood specimens were assayed for neutralizing RSV antibody titers. Infants hospitalized with a respiratory illness had a nasal aspirate obtained to determine whether RSV was present. Infants with an RSV respiratory hospitalization were matched by date of birth and geographic location to infants who did not have an RSV hospitalization before 6 months of age.

RESULTS

For every 1 log2 increase in titer of cord blood RSV neutralizing antibodies there was a 30% reduced risk of hospitalization with RSV (OR = 0.69, P = 0.003). However, among infants hospitalized with RSV, there was no association between cord blood RSV neutralizing antibody and the severity of the RSV illness.

CONCLUSIONS

These findings indicate that American Indian infants with high concentrations of maternally derived RSV neutralizing antibodies are protected from RSV hospitalization before 6 months of age. However, these antibodies do not modify the severity of illness once disease has occurred. The basis for elevated rates of RSV disease among American Indian infants cannot be attributed to a failure of maternal RSV neutralizing antibodies to confer protection.

Respiratory infections: pneumonia, lung abscess, and empyema

Pneumonia is an important clinical problem that affects children of all ages. Although effectively treated on an outpatient basis in the majority of cases, some children with respiratory infections still require hospitalization. This may be particularly true for patients with immunocompromise, for whom the lung represents the most common site of infection. Furthermore, respiratory infections represent a significant source of morbidity and mortality in this patient population. This article focuses on the clinical presentation, etiology, and treatment of childhood pneumonia, with special consideration given to the immunocompromised child. Two specific complications of pneumonia, lung abscess and empyema, are discussed.

Respiratory syncytial virus season and hospitalizations in the Alaskan Yukon-Kuskokwim Delta

From 1993 to 1996, Alaska Native infants younger than 1 year of age from the Yukon-Kuskokwim Delta region in Alaska experienced a respiratory syncytial virus (RSV) hospitalization rate 5 times higher than the U.S. general infant population rate. This article describes the trends in hospitalization and prolonged annual season of RSV hospitalizations in Yukon-Kuskokwim children from 1993 to 2004 and discusses factors associated with high rates of RSV hospitalization and the impact of interventions to decrease RSV hospitalizations in this population.

Sex differences in the incidence and severity of respiratory tract infections

Sex is a significant epidemiological factor for several diseases. However, the role of sex in the development and outcome of various infections has not been extensively studied with the notable exception of urinary tract infections. We searched in the PubMed database to identify articles that could provide relevant data regarding sex differences in the incidence and severity of respiratory tract infections (RTIs). We extracted data from 84 relevant studies that provided information regarding sex differences in the incidence and severity of RTIs. Females are more commonly affected with infections of the upper respiratory tract, specifically sinusitis, tonsillitis, and otitis externa. On the other hand, males are more commonly affected with otitis media, croup, and most important, lower RTIs. It is also evident from the reviewed evidence that the course of most RTIs is more severe in males than in females, leading to higher mortality in males, especially in community-acquired pneumonia. In conclusion, the available data suggest that males are more susceptible than females to most types of RTIs in all age groups (adults and children). Overall, it seems that males develop RTIs more frequently than females, except for sinusitis, otitis externa, and probably tonsillitis. Anatomic, lifestyle, behavioural, and socioeconomic differences between males and females may explain the observed findings. The role of sex hormones in the regulation of the immune system may also contribute to the reported sex differences in the incidence and severity of the various types of RTIs, especially in adolescents and adults.

Asthma hospitalizations among American Indian and Alaska Native people and for the general US population

STUDY OBJECTIVES

Asthma is one of the most common chronic diseases in the United States. High rates of asthma hospitalization have been reported for some ethnic minorities; however, asthma hospitalization rates for American Indian/Alaska Native (AI/AN) populations of all ages have not been studied. In this study, we examined and compared hospitalization rates for AI/AN populations and the general population in the United States.

DESIGN

Hospital discharge records with a first-listed diagnosis of asthma were evaluated for AI/AN populations and the US general population of all ages from 1988 to 2002.

RESULTS

The asthma hospitalization rate for AI/AN populations decreased from 17.8/10,000 per year in 1988 to 1990 to 12.9/10,000 per year in 2000 to 2002. The overall age-adjusted rate for 2000 to 2002 was slightly lower than that for the general US population (12.9/10,000 and 16.4/10,000, respectively). However, AI/AN populations living in the Southwest region (17.6/10,000) had the highest asthma hospitalization rate among the Indian Health Service regions and the rate from 2000 to 2002 was similar to that for the general US population. The 2000 to 2002 asthma hospitalization rate for AI/AN populations < 1 year of age (infants) was higher than that in US infants, and the rates for AI/AN age groups > or = 1 year were similar to or lower than those for the general US population.

CONCLUSIONS

While asthma was rarely reported among AI/AN populations before 1975, the average annual age-adjusted asthma hospitalization rate was only slightly lower for AI/AN populations than that for the US general population from 2000 to 2002. Furthermore, the asthma hospitalization rates for AI/AN populations living in the Southwest and East regions were similar to the rate for the general US population. Efforts to further increase asthma awareness and symptom recognition among AI/AN populations should be implemented to help to reduce asthma hospitalizations.

Portrait of outpatient visits and hospitalizations for acute infections in Nunavik preschool children

OBJECTIVE

Inuit children from around the world are burdened by a high rate of infectious diseases. The objective of this study was to evaluate the incidence rate of infections in Inuit preschool children from Nunavik (Northern Québec).

METHODS

The medical chart of 354 children from a previously recruited cohort was reviewed for the first five years of life. All outpatient visits that led to a diagnosis of acute infection and all admissions for acute infections were recorded.

RESULTS

Rates of outpatient visits for acute otitis media (AOM) were 2314, 2300, and 732 events/1000 child-years for children 0-11 months, 12-23 months, and 2-4 years, respectively. Rates of outpatient visits for lower respiratory tract infections (LRTI) were 1385, 930, and 328 events/1000 child-years, respectively. Rates of hospitalization for pneumonia were 198, 119, and 31 events/1000 child-years, respectively.

CONCLUSION

Inuit children from Nunavik have high rates of AOM and LRTI. Such rates were higher than that of other non-native North-American populations previously published. Admission for LRTI is up to 10 times more frequent in Nunavik compared to other Canadian populations.

Decline in respiratory syncytial virus hospitalizations in a region with high hospitalization rates and prolonged season

BACKGROUND

During 1993 to 1996, Alaska Native infants <1 year of age from the Yukon Kuskokwim (YK) Delta in Alaska experienced a respiratory syncytial virus (RSV) hospitalization rate 5 times the U.S. general infant population rate. We describe trends in lower respiratory tract infection (LRTI) and RSV hospitalizations in YK children from 1994 to 2004.

METHODS

We abstracted hospital dates, RSV test results and clinical information from the hospital records for YK children <3 years of age hospitalized between July 1994 and June 2004.

RESULTS

: The RSV hospitalization rate in YK Delta children <1 year of age decreased from 178 per 1000 infants per year (1994-1997) to 104 per 1000 infants per year (2001-2004) (P < 0.001), and the RSV hospitalization rate for premature infants decreased from 317 to 123 per 1000 infants per year (P < 0.001). The risk reduction for RSV hospitalization was greater in premature (relative risk, 0.39) than in term infants (relative risk, 0.60; P = 0.04). The rate of non-RSV LRTI hospitalizations increased from 153 to 215 per 1000 infants per year (P < 0.001). The median RSV season length was 30.5 weeks. Pneumonia was diagnosed in more than half of RSV admissions.

CONCLUSIONS

In YK infants, the RSV hospitalization rate decreased by one-third between 1994 and 2004; however, the overall LRTI hospitalization rate did not change. The median RSV season was twice as long as for the U.S. population. Palivizumab prophylaxis may be responsible for the larger decrease in the RSV hospitalization rate among premature infants; however, the 2001-2004 RSV hospitalization rate among YK infants remained 3 times higher than the U.S. infant rate.

Effect of prenatal exposure to polychlorinated biphenyls on incidence of acute respiratory infections in preschool Inuit children

OBJECTIVE

We set out to assess whether environmental prenatal exposure to polychlorinated biphenyls (PCBs) is associated with incidence of acute respiratory infections in preschool Inuit children.

STUDY DESIGN

We reviewed the medical charts of 343 children from 0 to 5 years of age and evaluated the associations between PCB-153 concentration in umbilical cord plasma and the incidence rates of acute otitis media (AOM) and of upper and lower respiratory tract infections (URTIs and LRTIs, respectively).

RESULTS

The incidence rates of AOM and LRTIs were positively associated with prenatal exposure to PCBs. Compared with children in the first quartile of exposure (least exposed), children in fourth quartile (most exposed) had rate ratios of 1.25 (p<0.001) and 1.40 (p<0.001) for AOM and LRTIs, respectively. There was no association between prenatal PCB exposure and incidence rate of URTIs or hospitalization.

CONCLUSION

Prenatal exposure to PCBs could be responsible for a significant portion of respiratory infections in children of this population.

Risk factors for hospitalization due to respiratory syncytial virus infection among infants in the Basque Country, Spain

This study analysed the role of several risk factors for hospitalization due to community-acquired, respiratory syncytial virus (RSV) infection. The risk factors detected in infants hospitalized for RSV infection in the first 24 months of life were compared with those in the general infant population in our region. There were 361 episodes of hospitalization in 357 infants. Eighty per cent of the infants did not present underlying conditions for severe RSV infection and only 10 (3%) were candidates for palivizumab prophylaxis. In multivariate analysis, birthweight of <2500 g was independently associated with hospitalization for RSV infection and was the most commonly detected medical risk factor. Other risk factors were maternal age at delivery <25 years, birth in the second half of the year, prematurity, suburban residence and congenital heart disease. In conclusion, together with well-known risk factors, we found that low birthweight was an independent factor for severe RSV infection.

Effect of altitude on hospitalizations for respiratory syncytial virus infection

OBJECTIVE

Respiratory syncytial virus (RSV) infection is the foremost cause of serious lower respiratory tract infection in young children and infants. Because higher rates of hospitalization for bronchiolitis and pneumonia have been noted in high-altitude regions, we hypothesized that physiologic responses to altitude would predispose children to more severe illness from RSV infection. This study examined the effect of residential altitude on hospitalizations for RSV infection in Colorado from 1998 through 2002.

METHODS

A geographic information system was used to assemble data for altitude and demographic variables by zip code-tabulation areas. Data then were linked with hospital discharge data for RSV infections. Poisson regression models were developed to explore correlations between hospitalization rates and residential altitude, after adjustment for socioeconomic differences in the underlying population.

RESULTS

RSV-associated hospitalizations averaged 15.9 per 1000 infants who were younger than 1 year and 1.8 per 1000 children who were 1 to 4 years of age per season. A multivariate analysis suggested that the rate of hospitalization for RSV-specific International Classification of Diseases, Ninth Revision, Clinical Modification codes increased 25% among infants who were younger than 1 year and 53% among children who were 1 to 4 years of age for every 1000-m increase in altitude. The risk for RSV-associated hospitalization was highest at elevations above 2500 m.

CONCLUSIONS

High altitude above 2500 m is a modest predictor for RSV-associated hospitalization. Practitioners in these regions should consider additional efforts to educate parents about RSV infection and its prevention and the importance of early treatment.

Validation of a pediatric caregiver diary to measure symptoms of postacute respiratory syncytial virus bronchiolitis

Acute respiratory syncytial virus (RSV)-induced bronchiolitis is often associated with continuing respiratory symptoms following hospitalization. To date, there is no validated objective measure to evaluate symptoms of RSV-induced bronchiolitis. We report on the reliability, validity, and responsiveness of the bronchiolitis caregiver diary (BCD) of symptoms and healthcare utilization associated with postacute RSV. The BCD measures four symptoms (daytime cough, wheeze, trouble breathing, and nighttime cough), healthcare utilization, and rescue medication for worsening of lung symptoms. Data from the 4-week treatment period of the reported prospective, placebo-controlled trial of montelukast for treatment of postacute RSV were used to assess reliability (internal consistency and test-retest), construct validity (cross-sectional and longitudinal correlations), discriminant validity (known-groups analyses), and responsiveness. The primary outcome of this study was the percentage of symptom-free days (SFD). The secondary outcome was a composite symptom score (CSS; average of daytime cough, wheezing, and trouble breathing). Cronbach's alpha of 0.85 indicated that the four symptoms were internally consistent, supporting a unidimensional scale structure. Test-retest reliabilities for the percentage of SFD and CSS were above the recommended cut point of 0.70. Cross-sectional and longitudinal correlations were sizeable and statistically significant, demonstrating construct validity. Hypothesized known-group differences were statistically significant in the appropriate direction. Responsiveness analyses indicated moderate effect sizes for percentage of SFD. In conclusion, the BCD provides a valid, reliable, and responsive tool for the assessment of symptoms of postacute RSV-induced bronchiolitis, capable of measuring moderate effect sizes, and demonstrating responsiveness to therapy.