Risk factors for recurrent wheezing following acute bronchiolitis: a 12-month follow-up

Pulmonary Function and Long-Term Respiratory Symptoms in Children and Adolescents After COVID-19

Background

Persistent respiratory symptoms after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in adults are frequent, and there can be long-term impairment of pulmonary function. To date, only preliminary evidence is available on persistent respiratory sequelae of SARS-CoV-2 in children and adolescents. Our objective was to examine the long-term effects of symptomatic and asymptomatic SARS-CoV-2 infections on pulmonary function in this age group in a single-center, controlled, prospective study.

Methods

Participants with serological or polymerase chain reaction-based evidence of SARS-CoV-2 infection were recruited from a population-based study of seroconversion rates. Multiple-breath washout (MBW), body plethysmography, and diffusion capacity testing were performed for children and adolescents. Participants were interviewed about their symptoms during the acute phase of infection and long-lasting symptoms. Cases were compared with SARS-CoV-2 seronegative controls from the same population-based study with and without history of respiratory infection within 6 months prior to assessment. Primary endpoints were differences in pulmonary function, including diffusion capacity and MBW, between participants with and without evidence of SARS-CoV-2 infection. Secondary endpoints included correlation between lung function and long-lasting symptoms as well as disease severity.

Findings

In total, 73 seropositive children and adolescents (5-18 years) were recruited after an average of 2.6 months (range 0.4-6.0) following SARS-CoV-2 infection. Among 19 patients (27.1%) who complained of persistent or newly emerged symptoms since SARS-CoV-2, 8 (11.4%) reported respiratory symptoms. No significant differences were detected in frequency of abnormal pulmonary function when comparing cases with 45 controls, including 14 (31.1%) with a history of previous infection (SARS-CoV-2: 12, 16.4%; controls: 12, 27.7%; odds ratio 0.54, 95% confidence interval 0.22-1.34). Only two patients with persistent respiratory symptoms showed abnormal pulmonary function. Multivariate analysis revealed reduced forced vital capacity (p = 0.012) in patients with severe SARS-CoV-2 infection.

Interpretation

Pulmonary function is rarely impaired in children and adolescents after SARS-CoV-2 infection, except from those with severe infection, and did not differ between SARS-CoV-2 and other previous infections, suggesting that SARS-CoV-2 is not more likely to cause pulmonary sequelae than other infections. The discrepancy between persisting respiratory symptoms and normal pulmonary function suggests a different underlying pathology such as dysfunctional breathing.

The role of respiratory syncytial virus- and rhinovirus-induced bronchiolitis in recurrent wheeze and asthma-A systematic review and meta-analysis

INTRODUCTION

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. RSV-induced bronchiolitis has been associated with preschool wheeze and asthma in cohort studies where the comparison groups consist of healthy infants. However, recent studies identify rhinovirus (RV)-induced bronchiolitis as a potentially stronger risk factor for recurrent wheeze and asthma.

AIM

This systematic review and meta-analysis aimed to compare the associations of RSV- and RV-induced bronchiolitis with the development of preschool wheeze and childhood asthma.

METHODS

We performed a systematic search of the published literature in five databases by using a MeSH term-based algorithm. Cohort studies that enrolled infants with bronchiolitis were included. The primary outcomes were recurrent wheeze and asthma diagnosis. Wald risk ratios and odds ratios (ORs) were estimated, along with their 95% confidence intervals (CIs). Individual and summary ORs were visualized with forest plots.

RESULTS

There were 38 studies included in the meta-analysis. Meta-analysis of eight studies that had data on the association between infant bronchiolitis and recurrent wheeze showed that the RV-bronchiolitis group were more likely to develop recurrent wheeze than the RSV-bronchiolitis group (OR 4.11; 95% CI 2.24-7.56). Similarly, meta-analysis of the nine studies that had data on asthma development showed that the RV-bronchiolitis group were more likely to develop asthma (OR 2.72; 95% CI 1.48-4.99).

CONCLUSION

This is the first meta-analysis that directly compares between-virus differences in the magnitude of virus-recurrent wheeze and virus-childhood asthma outcomes. RV-induced bronchiolitis was more strongly associated with the risk of developing wheeze and childhood asthma.

Does respiratory syncytial virus lower respiratory illness in early life cause recurrent wheeze of early childhood and asthma? Critical review of the evidence and guidance for future studies from a World Health Organization-sponsored meeting

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) and hospitalization in infants and children globally. Many observational studies have found an association between RSV LRTI in early life and subsequent respiratory morbidity, including recurrent wheeze of early childhood (RWEC) and asthma. Conversely, two randomized placebo-controlled trials of efficacious anti-RSV monoclonal antibodies (mAbs) in heterogenous infant populations found no difference in physician-diagnosed RWEC or asthma by treatment group. If a causal association exists and RSV vaccines and mAbs can prevent a substantial fraction of RWEC/asthma, the full public health value of these interventions would markedly increase. The primary alternative interpretation of the observational data is that RSV LRTI in early life is a marker of an underlying predisposition for the development of RWEC and asthma. If this is the case, RSV vaccines and mAbs would not necessarily be expected to impact these outcomes. To evaluate whether the available evidence supports a causal association between RSV LRTI and RWEC/asthma and to provide guidance for future studies, the World Health Organization convened a meeting of subject matter experts on February 12-13, 2019 in Geneva, Switzerland. After discussing relevant background information and reviewing the current epidemiologic evidence, the group determined that: (i) the evidence is inconclusive in establishing a causal association between RSV LRTI and RWEC/asthma, (ii) the evidence does not establish that RSV mAbs (and, by extension, future vaccines) will have a substantial effect on these outcomes and (iii) regardless of the association with long-term childhood respiratory morbidity, severe acute RSV disease in young children poses a substantial public health burden and should continue to be the primary consideration for policy-setting bodies deliberating on RSV vaccine and mAb recommendations. Nonetheless, the group recognized the public health importance of resolving this question and suggested good practice guidelines for future studies.

Factors Predicting Asthma in Children With Acute Bronchiolitis

OBJECTIVE

The aim of this study was to determine if there is an association between bronchiolitis and future development of asthma in children younger than 2 years.

METHODS

We reviewed the medical records of 1991 patients younger than 2 years presenting to the emergency department from January 2000 to December 2010 who received a clinical diagnosis of acute bronchiolitis. Their demographic information, the number of bronchiolitis episodes, and family history of asthma were recorded. The primary care clinic records of these children were reviewed for a period of 1 year following their presentation to the emergency department to determine if they had received a diagnosis of asthma. A stepwise logistic regression was performed to determine what factors were associated with future asthma development.

RESULTS

We reviewed the medical record of 1991 children with the diagnosis of bronchiolitis for subsequent development of asthma. The following variables were identified as predictors of subsequent asthma: male sex (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.05-1.55), family history of asthma (OR, 1.6; 95% CI, 1.33-1.95), atopy (OR, 1.4; 95% CI, 1.12-1.83), age older than 5 months (OR, 1.4 95% CI, 1.13-1.66), more than 2 episodes of bronchiolitis (OR, 2.4; 95% CI, 1.79-3.07), and allergies (OR1.6; 95% CI, 1.14-2.14).

CONCLUSIONS

In this limited sample, the predictor variables for asthma were male sex, age older than 5 months, more than 2 episodes of bronchiolitis, a history of atopy, and allergies.

Predictors of Inappropriate Use of Diagnostic Tests and Management of Bronchiolitis

Background

The aim of the present study was to determine predictors of inappropriate use of diagnostic tests and management of bronchiolitis in a population of hospitalized infants.

Methods

In an analytical cross-sectional study, we determined independent predictors of the inappropriate use of diagnostic tests and management of bronchiolitis in a population of hospitalized infants. We defined a composite outcome score as the main outcome variable.

Results

Of the 303 included patients, 216 (71.3%) experienced an inappropriate use of diagnostic tests and treatment of bronchiolitis. After controlling for potential confounders, it was found that atopic dermatitis (OR 5.30; CI 95% 1.14–24.79; p = 0.034), length of hospital stay (OR 1.48; CI 95% 1.08–2.03; p = 0.015), and the number of siblings (OR 1.92; CI 95% 1.13–3.26; p = 0.015) were independent predictors of an inappropriate use of diagnostic tests and treatment of the disease.

Conclusions

Inappropriate use of diagnostic tests and treatment of bronchiolitis was a highly prevalent outcome in our population of study. Participants with atopic dermatitis, a longer hospital stay, and a greater number of siblings were at increased risk for inappropriate use of diagnostic tests and management of the disease.

Gender- and age-specific risk factors for wheeze from birth through adolescence

BACKGROUND AND OBJECTIVE

Cross-sectional gender differences in wheeze are well documented, but few studies have examined the gender-specific risk factors for wheeze longitudinally. This study aims to identify gender- and age-specific risk factors for wheeze from birth through adolescence.

METHODS

The incidence of wheeze was ascertained every 6 months through age 14 years in a birth cohort consisting of 499 children with a parental history of atopy. Gender- and age-specific risk factors were identified through generalized estimating equations.

RESULTS

A total of 454 (91.0%) and 351 (70.3%) children were followed past age 7 and 13 years, respectively. Maternal asthma was a risk factor for wheeze in girls (OR = 2.05, 95% CI 1.44-2.91, P < 0.0001) and boys (OR = 1.79, 1.29-2.48, P = 0.0004) and had a similar effect on wheeze throughout the ages. Paternal asthma (OR = 1.83, 1.38-2.57, P = 0.0005) and infant bronchiolitis (OR = 2.15, 1.47-3.14, P < 0.0001) were risk factors for boys only, with similar effects throughout the ages.

CONCLUSION

Using a prospective cohort, we identified gender- and age-specific risk factors for wheeze. The identification of gender-specific early life risk factors may allow for timely interventions and a more personalized approach to the treatment of asthma.

Recurrent wheezing 36 months after bronchiolitis is associated with rhinovirus infections and blood eosinophilia

AIM

Links between respiratory syncytial virus bronchiolitis and asthma are well known, but few studies have dealt with wheezing following bronchiolitis induced by other viruses. We assessed the risk factors for recurrent wheezing in infants hospitalised for acute viral bronchiolitis.

METHODS

We followed 313 infants for three years after they were hospitalised for bronchiolitis, caused by 14 different viruses, to identify risk factors for recurrent wheezing. Parents provided feedback on wheezing episodes during telephone interviews 12 (n = 266), 24 (n = 242) and 36 (n = 230) months after hospitalisation.

RESULTS

The frequency of wheezing episodes diminished during the follow-up period: 137 children (51.7%) at 12 months, 117 (48.3%) at 24 months and 93 (40.4%) at 36 months. The risk of wheeze after three years was OR = 7.2 (95% CI 3.9-13.3) if they had episodes of wheezing during the first year after bronchiolitis, 16.8 (8.7-32.7) if they had episodes of wheezing during the second year and 55.0 (22.7-133.2) if they wheezed during both years. Blood eosinophils >400 cells/μL (OR 7.7; CI 1.4-41.8) and rhinovirus infections (3.1; 1.0-9.4) were the major risk factors for recurrent wheezing.

CONCLUSION

Recurrent wheezing 36 months after infant bronchiolitis was associated with rhinoviruses and blood eosinophilia.

Viral etiology of hospitalized acute lower respiratory infections in children under 5 years of age -- a systematic review and meta-analysis

AIM

To estimate the proportional contribution of influenza viruses (IV), parainfluenza viruses (PIV), adenoviruses (AV), and coronaviruses (CV) to the burden of severe acute lower respiratory infections (ALRI).

METHODS

The review of the literature followed PRISMA guidelines. We included studies of hospitalized children aged 0-4 years with confirmed ALRI published between 1995 and 2011. A total of 51 studies were included in the final review, comprising 56091 hospitalized ALRI episodes.

RESULTS

IV was detected in 3.0% (2.2%-4.0%) of all hospitalized ALRI cases, PIV in 2.7% (1.9%-3.7%), and AV in 5.8% (3.4%-9.1%). CV are technically difficult to culture, and they were detected in 4.8% of all hospitalized ALRI patients in one study. When respiratory syncytial virus (RSV) and less common viruses were included, at least one virus was detected in 50.4% (40.0%-60.7%) of all hospitalized severe ALRI episodes. Moreover, 21.9% (17.7%-26.4%) of these viral ALRI were mixed, including more than one viral pathogen. Among all severe ALRI with confirmed viral etiology, IV accounted for 7.0% (5.5%-8.7%), PIV for 5.8% (4.1%-7.7%), and AV for 8.8% (5.3%-13.0%). CV was found in 10.6% of virus-positive pneumonia patients in one study.

CONCLUSIONS

This article provides the most comprehensive analysis of the contribution of four viral causes to severe ALRI to date. Our results can be used in further cost-effectiveness analyses of vaccine development and implementation for a number of respiratory viruses.

[Consensus conference on acute bronchiolitis (VI): prognosis of acute bronchiolitis. Review of scientific evidence]

We present a review of the evidence on prognosis of acute bronchiolitis, risk factors for severe forms, symptom or severity scores and risk of post-bronchiolitis asthma. Documented risk factors of long stay or PICU admission in hospitalized patients are: bronchopulmonary dysplasia and/or chronic lung disease, prematurity, congenital heart disease and age less than 3 months. Other less well documented risk factors are: tobacco exposure, history of neonatal mechanical ventilation, breastfeeding for less than 4 months, viral co-infection and other chronic diseases. There are several markers of severity: toxic appearance, tachypnea, hypoxia, atelectasis or infiltrate on chest radiograph, increased breathing effort, signs of dehydration, tachycardia and fever. Although we have some predictive models of severity, none has shown sufficient predictive validity to recommend its use in clinical practice. While there are different symptom or severity scores, none has proven to be valid or accurate enough to recommend their preferable application in clinical practice. There seems to be a consistent and strong association between admission due to bronchiolitis and recurrent episodes of wheezing in the first five years of life. However it is unclear whether this association continues in subsequent years, as there are discordant data on the association between bronchiolitis and asthma.

High incidence of recurrent wheeze in children with down syndrome with and without previous respiratory syncytial virus lower respiratory tract infection

BACKGROUND

Respiratory syncytial virus (RSV)-induced lower respiratory tract infection (LRTI) is associated with the subsequent development of recurrent wheeze. In a recent study, we found a high incidence (9.9%) of hospitalization for RSV-induced LRTI among children with Down syndrome (DS), indicating DS as a new risk factor for RSV-induced LRTI. In the current study we aimed to investigate the development of long-term airway morbidity in children with DS after hospitalization for RSV-induced LRTI.

METHODS

A combined retrospective cohort and prospective birth cohort of children with DS with a history of hospitalization for RSV-induced LRTI was studied (n = 53). Three control populations were included: children with DS without hospitalization for RSV-induced LRTI (n = 110), children without DS but with hospitalization for RSV-induced LRTI (n = 48), and healthy siblings of the previous 3 groups mentioned (n = 49). The primary outcome was physician-diagnosed wheeze up to 2 years of age.

RESULTS

The incidence of physician-diagnosed recurrent wheeze in children with DS with a history of hospitalization for RSV-induced LRTI was 36%. Unexpectedly, up to 30% of children with DS without a history of RSV-induced LRTI had physician-diagnosed recurrent wheeze (no significant difference). In children without DS physician-diagnosed wheeze was found more frequently in children hospitalized for RSV-induced LRTI than healthy controls (31% vs. 8%, P = 0.004).

CONCLUSIONS

In this combined retrospective/prospective cohort study RSV-induced LRTI did not significantly contribute to the risk of recurrent wheeze in children with DS. An unexpected finding was that recurrent wheeze was very common among children with DS.

The association between respiratory syncytial virus infection and the development of childhood asthma: a systematic review of the literature

BACKGROUND

The relation between early respiratory syncytial virus (RSV) infection and later emergence of episodes of wheezing/asthma remains a subject of debate. We carried out a systematic review of studies of the association between RSV infection in the first 36 months of life and the subsequent development of asthma/bronchial hyperreactivity.

METHODS

A literature search for original studies on RSV respiratory infection published in English or Spanish over the last 21 years was conducted in the bibliographic databases Medline, Embase, and Indice Médico Español, and in the Cochrane library. Articles were included if they described original studies of confirmed RSV infection in children under 3 years of age, and had defined outcome variables. The methodologic quality of articles included in the review was evaluated according to the Hadorn criteria.

RESULTS

The review included 12 original articles that respond to the research question. The studies evaluated showed that RSV lower respiratory tract infection is associated with an increased risk for subsequent development of asthma/recurrent wheezing, and that this association becomes progressively smaller with increasing age.

CONCLUSION

On the basis of this systematic review of the literature, it can be concluded that a significant association exists between RSV infection in childhood and the long-term development of subsequent episodes of recurrent wheezing or asthma. However, the methodologic quality of the articles evaluated is limited, and hence additional studies are needed, ideally, with specific therapeutic interventions aimed at reducing RSV replication.

Diminished lung function, RSV infection, and respiratory morbidity in prematurely born infants

BACKGROUND

Diminished lung function appears to be a risk factor for respiratory syncytial virus (RSV) infection/bronchiolitis in term born infants.

AIMS

To determine if diminished lung function prior to neonatal unit discharge was associated with subsequent symptomatic RSV lower respiratory tract infection (LRTI) and respiratory morbidity in prematurely born infants.

METHODS

Of 39 infants in a tertiary neonatal intensive care unit (median gestational age 28 weeks, range 23-31), 20 had bronchopulmonary dysplasia. Lung function (compliance and resistance of the respiratory system (C(rs) and R(rs)) and functional residual capacity (FRC)) was measured on the neonatal unit at 36 weeks postmenstrual age (PMA). Following neonatal unit discharge, nasopharyngeal aspirates were obtained on every occasion, at home or in hospital, an infant had an LRTI. RSV was identified by immunofluorescence and/or culture.

RESULTS

The 15 infants who suffered a symptomatic RSV LRTI had a higher mean R(rs) and suffered more wheeze at follow up than the rest of the cohort. Regression analysis showed that a high R(rs) was significantly associated with a symptomatic RSV LRTI; significant factors for cough were a high R(rs) and a symptomatic RSV LRTI, and for wheeze were a high R(rs).

CONCLUSION

Prematurely born infants, who had a symptomatic RSV LRTI and/or respiratory morbidity at follow up, had worse lung function prior to neonatal unit discharge.

Prospective study of healthcare utilisation and respiratory morbidity due to RSV infection in prematurely born infants

BACKGROUND

A study was undertaken to determine the impact of respiratory syncytial virus (RSV) infection, both in hospital and the community, on healthcare utilisation and respiratory morbidity in prematurely born infants and to identify risk factors for symptomatic RSV infection.

METHODS

A hospital and community follow up study was undertaken of 126 infants born before 32 weeks of gestational age. Healthcare utilisation (hospital admissions and general practitioner attendances) in the first year, respiratory morbidity at follow up (wheeze and cough documented by parent completed diary cards), and RSV positive lower respiratory tract infections (LRTIs) were documented. Nasopharyngeal aspirates were obtained for immunofluorescence and culture for RSV whenever the infants had an LRTI, either in the community or in hospital.

RESULTS

Forty two infants had an RSV positive LRTI (RSV group), 50 had an RSV negative LRTI (RSV negative LRTI group), and 32 infants had no LRTI (no LRTI group). Compared with the RSV negative LRTI and the no LRTI groups, the RSV group required more admissions (p=0.392, p<0.001) and days in hospital (p=0.049, p=0.006) and had more cough (p=0.05, p=0.038) and wheeze (p=0.003, p=0.003) at follow up. Significant risk factors for symptomatic RSV LRTI were number of siblings (p=0.035) and maternal smoking in pregnancy (p=0.005), for cough were number of siblings (p=0.002) and RSV LRTI (p=0.02), and for wheeze was RSV LRTI (p=0.019).

CONCLUSION

RSV infection, even if hospital admission is not required, is associated with increased subsequent respiratory morbidity in prematurely born infants.

Contribution of respiratory syncytial virus G antigenicity to vaccine-enhanced illness and the implications for severe disease during primary respiratory syncytial virus infection

BACKGROUND

Immunization of BALB/c mice with vaccinia virus expressing the G glycoprotein (vvG) of respiratory syncytial virus (RSV) or with formalin-inactivated alum-precipitated RSV (FI-RSV) predisposes for severe illness, type 2 cytokine production and pulmonary eosinophilia after challenge with live RSV. This similar disease profile has led to the proposal that the presence of the G glycoprotein in the FI-RSV preparation was the immunologic basis for the vaccine-associated enhancement of disease observed in the failed clinical trials of the 1960s. However, processes of disease pathogenesis observed in FI-RSV- and vvG-immunized mice suggest that FI-RSV and vvG immunizations induce immune responses of different compositions and requirements that converge to produce similar disease outcomes upon live virus challenge.

METHODS

The potential role of RSV G present in FI-RSV preparations in increasing postimmunization disease severity was explored in mice.

RESULTS

The absence of RSV G or its immunodominant epitope during FI-RSV immunization does not reduce disease severity after RSV challenge. Furthermore although depletion of V beta 14+ T cells during RSV challenge modulates disease in G-primed mice, minimal impact on disease in FI-RSV-immunized mice is observed.

CONCLUSION

FI-RSV vaccine-enhanced illness is not attributable to RSV G. Furthermore formulation of a safe and effective RSV vaccine must ensure RSV antigen production, processing and presentation via the endogenous pathways. Thus gene delivery by vector, by DNA or by live attenuated virus are attractive vaccine approaches.