A modern miasma hypothesis and back-to-school asthma exacerbations

Pathogenic Role of Human Rhinovirus Mono-Infection in Pediatric Lower Respiratory Tract Infection

Background and objective Human rhinovirus (HRV) is one of the leading causes of pediatric respiratory tract infection with a prevalence rate of 30-50%, mostly affecting children below five years of age and causing a substantial amount of economic loss. In children, it can alone or as a co-infection, cause a wide range of symptoms from mild to life-threatening ones. With the above background, the current study was carried out to emphasize the role of HRV mono-infection in pediatric acute respiratory tract infections by correlating clinical and molecular laboratory findings. Methods This study was carried out in a tertiary care teaching hospital over a duration of four years (March 2019-October 2023). Children up to 14 years of age visiting the outpatient department or admitted to the ward with diagnoses of acute respiratory tract infections (ARTIs) were included. The clinical and laboratory data were retrieved and analyzed. A nasopharyngeal swab (NPS) or throat swab (TS) was collected and sent to the Microbiology laboratory maintaining the cold chain. Nucleic acid was extracted and subjected to multiplex real-time polymerase chain reaction (RT-PCR). Result Of the 245 samples tested for the respiratory viral pathogen, 52 samples tested positive for HRV, of which 27 had HRV mono-infection. The clinico-demographic details of these 27 patients were studied in detail. The majority of the cases (24/27; 88.8%) were less than five years of age. Fever and shortness of breath were the most consistent symptoms in all. Nineteen (19/27; 62.9%) HRV mono-infection cases had underlying co-morbidities, all requiring respiratory support. The HRV mono-infection cases either developed bronchiolitis, lower respiratory tract infection, or pneumonia. All mono-infection cases had cycle threshold value (Ct) < 25, while the Ct value of HRV was > 30 in co-infection with other viruses. Conclusion Mono-infection of HRV in under-five children with underlying comorbidities and a lesser Ct value indicates severe disease manifestation and should be dealt with more cautiously.

Understanding Rhinovirus Circulation and Impact on Illness

Rhinoviruses (RVs) have been reported as one of the main viral causes for severe respiratory illnesses that may require hospitalization, competing with the burden of other respiratory viruses such as influenza and RSV in terms of severity, economic cost, and resource utilization. With three species and 169 subtypes, RV presents the greatest diversity within the Enterovirus genus, and despite the efforts of the research community to identify clinically relevant subtypes to target therapeutic strategies, the role of species and subtype in the clinical outcomes of RV infection remains unclear. This review aims to collect and organize data relevant to RV illness in order to find patterns and links with species and/or subtype, with a specific focus on species and subtype diversity in clinical studies typing of respiratory samples.

Monitoring epidemiological trends in back to school asthma among preschool and school-aged children using real-time syndromic surveillance in England, 2012-2016

BACKGROUND : Back to school (BTS) asthma has been previously reported in children; however, its epidemiology and associated healthcare burden are unclear. We aimed to describe the timing and magnitude of BTS asthma using surveillance data from different health services in England. METHODS : Asthma morbidity data from emergency department attendances and general practitioner (GP) consultations between April 2012 and December 2016 were used from national syndromic surveillance systems in England. Age-specific and sex-specific rates and time series of asthma peaks relative to school term dates were described. The timing of a BTS excess period and adjusted rates of asthma relative to a baseline period were estimated using cumulative sum control chart plots and negative binomial regression. RESULTS : BTS asthma among children aged below 15 years was most pronounced at the start of the school year in September. This effect was not present among those aged 15 years and above. After controlling for sex and study year, the adjusted daily rate of childhood GP in-hours asthma consultations was 2.5-3 times higher in the BTS excess period, with a significantly higher effect among children aged 0-4 years. A distinct age-specific pattern of sex differences in asthma presentations was present, with a higher burden among males in children and among females aged over 15 years. CONCLUSION: We found evidence of a BTS asthma peak in children using surveillance data across a range of healthcare systems, supporting the need for further preventative work to reduce the impact of BTS asthma in children.

Interventions for autumn exacerbations of asthma in children

BACKGROUND

Asthma exacerbations in school-aged children peak in autumn, shortly after children return to school following the summer holiday. This might reflect a combination of risk factors, including poor treatment adherence, increased allergen and viral exposure, and altered immune tolerance. Since this peak is predictable, interventions targeting modifiable risk factors might reduce exacerbation-associated morbidity and strain upon health resources. The peak occurs in September in the Northern Hemisphere and in February in the Southern Hemisphere.

OBJECTIVES

To assess the effects of pharmacotherapy and behavioural interventions enacted in anticipation of school return during autumn that are designed to reduce asthma exacerbations in children during this period.

SEARCH METHODS

We searched the Cochrane Airways Group Trials Register, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, reference lists of primary studies and existing reviews, and manufacturers' trial registries (Merck, Novartis and Ono Parmaceuticals). We searched databases from their inception to 1 December 2017, and imposed no restriction on language of publication.

SELECTION CRITERIA

We included all randomised controlled trials comparing interventions aimed specifically at reducing autumn exacerbations with usual care, (no systematic change in management in preparation for school return). We included studies providing data on children aged 18 years or younger.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently screened records identified by the search and then extracted data and assessed bias for trials meeting the inclusion criteria. A third review author checked for accuracy and mediated consensus on disagreements. The primary outcome was proportion of children experiencing one or more asthma exacerbations requiring hospitalisation or oral corticosteroids during the autumn period.

MAIN RESULTS

Our searches returned 546 trials, of which five met our inclusion criteria. These studies randomised 14,252 children to receive either an intervention or usual care. All studies were conducted in the Northern Hemisphere. Three interventions used a leukotriene receptor antagonist, one used omalizumab or a boost of inhaled corticosteroids, and the largest study, (12,179 children), used a medication reminder letter. Whilst the risk of bias within individual studies was generally low, we downgraded the evidence quality due to imprecision associated with low participant numbers, poor consistency between studies, and indirect outcome ascertainment.A US study of 513 children with mild/severe asthma and allergic sensitisation was the only study to provide data for our primary outcome. In this study, the proportion of participants experiencing an exacerbation requiring oral corticosteroids or hospital admission in the 90 days after school return was significantly reduced to 11.3% in those receiving omalizumab compared to 21.0% in those receiving placebo (odds ratio 0.48, 95% confidence interval 0.25 to 0.92, moderate-quality evidence). The remaining studies used alternative exacerbation definitions. When data from two leukotriene receptor antagonist studies with comparable outcomes were combined in a random-effects model, there was no evidence of an effect upon exacerbations. There was no evidence that a seasonal medication reminder letter decreased unscheduled contacts for a respiratory diagnosis between September and December.Four studies recorded adverse events. There was no evidence that the proportion of participants experiencing at least one adverse event differed between intervention and usual care groups. Lack of data prevented planned subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

Seasonal omalizumab treatment from four to six weeks before school return might reduce autumn asthma exacerbations. We found no evidence that this strategy is associated with increased adverse effects other than injection site pain, but it is costly. There were no data upon which to judge the effect of this or other seasonal interventions on asthma control, quality of life, or asthma-related death. In future studies definitions of exacerbations should be provided, and standardised where possible. To investigate possible differential effects according to subgroup, participants in future trials should be well characterised with respect to baseline asthma severity and exacerbation history in addition to age and gender.

The school environment and asthma in childhood

In this article, we discuss the relationship between environmental exposures within the school environment and pediatric asthma morbidity. This article will conclude by reviewing novel school based asthma education and therapeutic programs and environmental interventions designed to help mitigate pediatric asthma morbidity.

Absence of back to school peaks in human rhinovirus detections and respiratory symptoms in a cohort of children with asthma

Much of what is known about the seasonality of human rhinovirus (hRV) infections has been learned from the study of acute asthma exacerbations presenting to emergency care, including those among children at the start of the school term. Much less is known about the patterns of hRVs in the community. In this study, viruses and day-to-day symptoms of asthma and colds were monitored twice weekly in 67 children with asthma aged 5-12 years, over a 15 month period in Sydney, Australia. Overall hRV was detected in 314/1232 (25.5%) of nasal wash samples and 142/1231 (11.5%) of exhaled breath samples; of these, 231 and 24 respectively were genotyped. HRVs were detected with similar prevalence rate throughout the year, including no peak in hRV prevalence following return to school. No peaks were seen in asthma and cold symptoms using twice-weekly diary records. However, over the same period in the community, there were peaks in asthma emergency visits both at a large local hospital and in state-wide hospitalizations, following both return to school (February) and in late autumn (May) in children of the same age. This study suggests that hRV infections are common throughout the year among children, and differences in virus prevalence alone may not account for peaks in asthma symptoms.

Bedroom air quality and vacuuming frequency are associated with repeat child asthma hospital admissions

OBJECTIVE

Indoor environment factors have been associated with risk of asthma exacerbations in children but little is known about their role on asthma hospital readmissions. As children in Western societies continually spend more time indoors, understanding the influence of these factors on asthma exacerbation is important. We examined the role of indoor environmental and lifestyle characteristics on child asthma readmissions.

METHODS

A hospital-based case-control study recruited 22 children readmitted for asthma and 22 controls not readmitted for asthma. Logistic regression models were used to examine the association between aeroallergens and fungi in the bedroom and indoor lifestyle characteristics factors for asthma readmissions. To determine the best possible set of predictors among a large set of risk factors, we used random forests (RF) techniques.

RESULTS

Higher levels of airborne Cladosporium and yeast in the child's bedroom increased risk of readmission (OR = 1.68, 95% CI 1.04-2.72 and OR = 1.52, 95% CI 0.99-2.34, respectively). Carpeted floors in the bedroom and synthetic doonas were also associated with increase in asthma readmissions (OR = 4.07, 95% CI 1.03-16.06 and OR = 14.6, 95% CI 1.26-169.4, respectively). In the home, frequent vacuuming using bagged cleaners increased risk of asthma readmission OR = 15.7 (95% CI 2.82-87.2).

CONCLUSIONS

Factors in the child's bedroom play an important role in increasing the risk of asthma hospital readmissions. These findings have major clinical implications as the identified potential risk factors may be modifiable. Further epidemiological studies with larger samples are necessary to evaluate these associations further.

Inappropriate prescribing of inhaled corticosteroids: are they being prescribed for respiratory tract infections? A retrospective cohort study

BACKGROUND

Guidelines recommend regular use of inhaled corticosteroid (ICS)-containing medications for all patients with persistent asthma and those with moderate to severe chronic obstructive pulmonary disease. It is important to identify indicators of inappropriate prescribing.

AIMS

To test the hypothesis that ICS are prescribed for the management of respiratory infections in some patients lacking evidence of chronic airways disease.

METHODS

Medication dispensing data were obtained from the Australian national Pharmaceutical Benefits Scheme (PBS) for concessional patients dispensed any respiratory medications during 2008. We identified people dispensed only one ICS-containing medication and no other respiratory medications in a year, who were therefore unlikely to have chronic airways disease, and calculated the proportion who were co-dispensed oral antibiotics.

RESULTS

In 2008, 43.6% of the 115,763 patients who were dispensed one-off ICS were co-dispensed oral antibiotics. Co-dispensing was seasonal, with a large peak in winter months. The most commonly co-dispensed ICS among adults were moderate/high doses of combination therapy, while lower doses of ICS alone were co-dispensed among children. In this cohort, one-off ICS co-dispensed with oral antibiotics cost the government $2.7 million in 2008.

CONCLUSIONS

In Australia, many people who receive one-off prescriptions for ICS-containing medications do not appear to have airways disease. In this context, the high rate of co-dispensing with antibiotics suggests that ICS are often inappropriately prescribed for the management of symptoms of respiratory infection. Interventions are required to improve the quality of prescribing of ICS and the management of respiratory infections in clinical practice.