A surge in human metapneumovirus paediatric respiratory admissions in Western Australia following the reduction of SARS-CoV-2 non-pharmaceutical interventions.

AIM: Western Australian laboratory data demonstrated a decrease in human metapneumovirus (hMPV) detections through 2020 associated with SARS-CoV-2-related non-pharmaceutical interventions (NPIs), followed by a subsequent surge in metropolitan region in mid-2021. We aimed to assess the impact of the surge in hMPV on paediatric hospital admissions and the contribution of changes in testing. METHODS: All respiratory-coded admissions of children aged <16 years at a tertiary paediatric centre between 2017 and 2021 were matched with respiratory virus testing data. Patients were grouped by age at presentation and by ICD-10 AM codes into bronchiolitis, other acute lower respiratory infection (OALRI), wheeze and upper respiratory tract infection (URTI). For analysis, 2017-2019 was utilised as a baseline period. RESULTS: hMPV-positive admissions in 2021 were more than 2.8 times baseline. The largest increase in incidence was observed in the 1-4 years group (incidence rate ratio (IRR) 3.8; 95% confidence interval (CI): 2.5-5.9) and in OALRI clinical phenotype (IRR 2.8; 95% CI: 1.8-4.2). The proportion of respiratory-coded admissions tested for hMPV in 2021 doubled (32-66.2%, P < 0.001), with the greatest increase in wheeze (12-75% in 2021, P < 0.001). hMPV test percentage positivity in 2021 was higher than in the baseline period (7.6% vs. 10.1% in 2021, P = 0.004). CONCLUSION: The absence and subsequent surge underline the susceptibility of hMPV to NPIs. Increased hMPV-positive admissions in 2021 can be partially attributable to testing, but test-positivity remained high, consistent with a genuine increase. Continued comprehensive testing will help ascertain true burden of hMPV respiratory diseases.

Effect of Early High-Flow Nasal Oxygen vs Standard Oxygen Therapy on Length of Hospital Stay in Hospitalized Children With Acute Hypoxemic Respiratory Failure: The PARIS-2 Randomized Clinical Trial.

Importance: Nasal high-flow oxygen therapy in infants with bronchiolitis and hypoxia has been shown to reduce the requirement to escalate care. The efficacy of high-flow oxygen therapy in children aged 1 to 4 years with acute hypoxemic respiratory failure without bronchiolitis is unknown. Objective: To determine the effect of early high-flow oxygen therapy vs standard oxygen therapy in children with acute hypoxemic respiratory failure. Design, Setting, and Participants: A multicenter, randomized clinical trial was conducted at 14 metropolitan and tertiary hospitals in Australia and New Zealand, including 1567 children aged 1 to 4 years (randomized between December 18, 2017, and March 18, 2020) requiring hospital admission for acute hypoxemic respiratory failure. The last participant follow-up was completed on March 22, 2020. Interventions: Enrolled children were randomly allocated 1:1 to high-flow oxygen therapy (n = 753) or standard oxygen therapy (n = 764). The type of oxygen therapy could not be masked, but the investigators remained blinded until the outcome data were locked. Main Outcomes and Measures: The primary outcome was length of hospital stay with the hypothesis that high-flow oxygen therapy reduces length of stay. There were 9 secondary outcomes, including length of oxygen therapy and admission to the intensive care unit. Children were analyzed according to their randomization group. Results: Of the 1567 children who were randomized, 1517 (97%) were included in the primary analysis (median age, 1.9 years [IQR, 1.4-3.0 years]; 732 [46.7%] were female) and all children completed the trial. The length of hospital stay was significantly longer in the high-flow oxygen group with a median of 1.77 days (IQR, 1.03-2.80 days) vs 1.50 days (IQR, 0.85-2.44 days) in the standard oxygen group (adjusted hazard ratio, 0.83 [95% CI, 0.75-0.92]; P < .001). Of the 9 prespecified secondary outcomes, 4 showed no significant difference. The median length of oxygen therapy was 1.07 days (IQR, 0.50-2.06 days) in the high-flow oxygen group vs 0.75 days (IQR, 0.35-1.61 days) in the standard oxygen therapy group (adjusted hazard ratio, 0.78 [95% CI, 0.70-0.86]). In the high-flow oxygen group, there were 94 admissions (12.5%) to the intensive care unit compared with 53 admissions (6.9%) in the standard oxygen group (adjusted odds ratio, 1.93 [95% CI, 1.35-2.75]). There was only 1 death and it occurred in the high-flow oxygen group. Conclusions and Relevance: Nasal high-flow oxygen used as the initial primary therapy in children aged 1 to 4 years with acute hypoxemic respiratory failure did not significantly reduce the length of hospital stay compared with standard oxygen therapy. Trial Registration: anzctr.org.au Identifier: ACTRN12618000210279.

Influence of weather on incidence of bronchiolitis in Australia and New Zealand.

AIM: We aimed to examine the impact of weather on hospital admissions with bronchiolitis in Australia and New Zealand. METHODS: We collected data for inpatient admissions of infants aged 2-12 months to seven hospitals in four cities in Australia and New Zealand from 2009 until 2011. Correlation of hospital admissions with minimum daily temperature, wind speed, relative humidity and rainfall was examined using linear, Poisson and negative binomial regression analyses as well as general estimated equation models. To account for possible lag between exposure to weather and admission to hospital, analyses were conducted for time lags of 0-4 weeks. RESULTS: During the study period, 3876 patients were admitted to the study hospitals. Hospital admissions showed strong seasonality with peaks in wintertime, onset in autumn and offset in spring. The onset of peak incidence was preceded by a drop in temperature. Minimum temperature was inversely correlated with hospital admissions, whereas wind speed was directly correlated. These correlations were sustained for time lags of up to 4 weeks. Standardised correlation coefficients ranged from -0.14 to -0.54 for minimum temperature and from 0.18 to 0.39 for wind speed. Relative humidity and rainfall showed no correlation with hospital admissions in our study. CONCLUSION: A decrease in temperature and increasing wind speed are associated with increasing incidence of bronchiolitis hospital admissions in Australia and New Zealand.

Unusual 2020 respiratory syncytial virus bronchiolitis season in Western Australia: Not explained by weather.

OBJECTIVE: To describe and explore the relationship between weather and the unusual 2020 bronchiolitis season in Western Australia during the COVID-19 pandemic. METHODS: Correlation of meteorological data and presentations of infants with bronchiolitis through the ED of Perth Children's Hospital. RESULTS: The 2020 bronchiolitis epidemic showed a reversal of the usual seasonal pattern. There were no weather events to account for this phenomenon. CONCLUSIONS: The bronchiolitis outbreak showed no relationship to local weather patterns. State-mandated COVID-19 public health measures appear as the likely rationale.

Examining the interseasonal resurgence of respiratory syncytial virus in Western Australia.

BACKGROUND: Following a relative absence in winter 2020, a large resurgence of respiratory syncytial virus (RSV) detections occurred during the 2020/2021 summer in Western Australia. This seasonal shift was linked to SARS-CoV-2 public health measures. We examine the epidemiology and RSV testing of respiratory-coded admissions, and compare clinical phenotype of RSV-positive admissions between 2019 and 2020. METHOD: At a single tertiary paediatric centre, International Classification of Diseases, 10th edition Australian Modification-coded respiratory admissions longer than 12 hours were combined with laboratory data from 1 January 2019 to 31 December 2020. Data were grouped into bronchiolitis, other acute lower respiratory infection (OALRI) and wheeze, to assess RSV testing practices. For RSV-positive admissions, demographics and clinical features were compared between 2019 and 2020. RESULTS: RSV-positive admissions peaked in early summer 2020, following an absent winter season. Testing was higher in 2020: bronchiolitis, 94.8% vs 89.2% (p=0.01); OALRI, 88.6% vs 82.6% (p=0.02); and wheeze, 62.8% vs 25.5% (p<0.001). The 2020 peak month, December, contributed almost 75% of RSV-positive admissions, 2.5 times the 2019 peak. The median age in 2020 was twice that observed in 2019 (16.4 vs 8.1 months, p<0.001). The proportion of RSV-positive OALRI admissions was greater in 2020 (32.6% vs 24.9%, p=0.01). There were no clinically meaningful differences in length of stay or disease severity. INTERPRETATION: The 2020 RSV season was in summer, with a larger than expected peak. There was an increase in RSV-positive non-bronchiolitis admissions, consistent with infection in older RSV-naïve children. This resurgence raises concern for regions experiencing longer and more stringent SARS-CoV-2 public health measures.

Multicentre, randomised trial to investigate early nasal high-flow therapy in paediatric acute hypoxaemic respiratory failure: a protocol for a randomised controlled trial-a Paediatric Acute respiratory Intervention Study (PARIS 2).

INTRODUCTION: Acute hypoxaemic respiratory failure (AHRF) in children is the most frequent reason for non-elective hospital admission. During the initial phase, AHRF is a clinical syndrome defined for the purpose of this study by an oxygen requirement and caused by pneumonia, lower respiratory tract infections, asthma or bronchiolitis. Up to 20% of these children with AHRF can rapidly deteriorate requiring non-invasive or invasive ventilation. Nasal high-flow (NHF) therapy has been used by clinicians for oxygen therapy outside intensive care settings to prevent escalation of care. A recent randomised trial in infants with bronchiolitis has shown that NHF therapy reduces the need to escalate therapy. No similar data is available in the older children presenting with AHRF. In this study we aim to investigate in children aged 1 to 4 years presenting with AHRF if early NHF therapy compared with standard-oxygen therapy reduces hospital length of stay and if this is cost-effective compared with standard treatment. METHODS AND ANALYSIS: The study design is an open-labelled randomised multicentre trial comparing early NHF and standard-oxygen therapy and will be stratified by sites and into obstructive and non-obstructive groups. Children aged 1 to 4 years (n=1512) presenting with AHRF to one of the participating emergency departments will be randomly allocated to NHF or standard-oxygen therapy once the eligibility criteria have been met (oxygen requirement with transcutaneous saturation <92%/90% (dependant on hospital standard threshold), diagnosis of AHRF, admission to hospital and tachypnoea ≥35 breaths/min). Children in the standard-oxygen group can receive rescue NHF therapy if escalation is required. The primary outcome is hospital length of stay. Secondary outcomes will include length of oxygen therapy, proportion of intensive care admissions, healthcare resource utilisation and associated costs. Analyses will be conducted on an intention-to-treat basis. ETHICS AND DISSEMINATION: Ethics approval has been obtained in Australia (HREC/15/QRCH/159) and New Zealand (HDEC 17/NTA/135). The trial commenced recruitment in December 2017. The study findings will be submitted for publication in a peer-reviewed journal and presented at relevant conferences. Authorship of all publications will be decided by mutual consensus of the research team. TRIAL REGISTRATION NUMBER: ACTRN12618000210279.

Computed tomography for head injuries in children: Change in Australian usage rates over time.

OBJECTIVE: Paediatric head injury is a common presentation to the ED. North American studies demonstrate increasing use of computed tomography (CT) brain scan (CTB) to investigate head injury. No such data exists for Australian EDs. The aim of this study was to describe CTB use in head injury over time in eight Australian EDs. METHODS: Retrospective ED electronic database and medical imaging database audit was undertaken for the years 2001-2010 by International Classification of Diseases (ICD) 9 or 10 code for head injury in children <16 years. EDs and medical imaging departments of eight hospitals in Australia (five tertiary referral and three mixed departments). Data for ED presentations with head injury, and all CTB performed by medical imaging were merged to obtain a data set of CTB performed within 24 h for head injury-related attendances to the ED. Descriptive and comparative analysis of CTB rates was performed. RESULTS: The rate of CTB over the decade was 10.2% (95% confidence interval (CI) 9.9-10.5). The annual rate varied from 9.5% (95% CI 8.2-10.9) to 12.5% (95% CI 11.2-13.9). CTB use did not increase over time. Median year of age at time of CT scan was 4 years, with an interquartile range of 1.5-9.4 years. Overall there was a 9.2% increase in the CTB scan rate for every additional year of age at presentation (95% CI 6.6-12.1; P < 0.001). CONCLUSION: CTB use in head injuries did not increase during the study period, and rates of CTB were less than reported for North America.