Asthma admission among children in Hong Kong during the first year of the COVID-19 pandemic.

BACKGROUND: Multiple nonpharmaceutical interventions (NPIs) had been introduced in Hong Kong during coronavirus disease 2019 (COVID-19) pandemic. The impact on asthma admission, which was closely related to viral infection, was of concern. OBJECTIVE: The study aimed to identify the impact of NPIs on pediatric asthma admissions and their association with respiratory viruses. METHODS: We conducted a retrospective observational study to compare the difference in pediatric asthma hospital admission rates between pre-COVID-19 and COVID-19 periods. Information on demographics, nasopharyngeal specimen results, ventilatory support, intensive care admission, hospital stay duration, asthma control therapy, and previous admission episodes was collected. Weather parameters including temperature, rainfall, humidity, and air quality data that was reflected by the air quality health index were recorded. RESULTS: A total of 1808 pediatric asthma admissions were recorded during the pre-COVID-19 period while there were 62 admissions during COVID-19 period, among which 54 admissions from the pre-COVID-19 period and 4 admissions from COVID-19 period were excluded. Weekly pediatric asthma admissions per total pediatric admissions during COVID-19 was one-third of that during the pre-COVID-19 period (0.3% vs. 0.9%, p < 0.001). During COVID-19 period, a significantly lower percentage of respiratory virus isolates was noted (58.6% vs. 72.6%, p = 0.019). Poisson regression analysis showed that the COVID-19 period (odds ratio [OR] = 0.202, 95% confidence interval  [CI, 0.16-0.26]; p ≤ 0.001), summer vacation period (OR = 0.512, 95% CI [0.43-0.62]; p ≤ 0.001), and humidity (OR = 0.99, 95% CI [0.98-1.00]; p = 0.004) were independent protective factors for asthma admission. CONCLUSIONS: There was a significant reduction in pediatric asthma hospitalizations and respiratory virus isolates in the first year of COVID-19 pandemic in Hong Kong with the implementation of NPIs. Rhinovirus remained the key respiratory virus isolate. Incorporation of appropriate NPIs in long run could reduce virus infection-related pediatric asthma admission.

Longer term follow up of aerobic capacity in children affected by severe acute respiratory syndrome (SARS).

BACKGROUND: A study was undertaken to investigate the aerobic capacity and pulmonary function of children 6 and 15 months after the diagnosis of severe acute respiratory syndrome (SARS). METHODS: Thirty four patients of mean age 14.7 years completed both pulmonary function and maximal aerobic capacity tests at 6 months. All had normal clinical examination and were asymptomatic. Their exercise responses were compared with a group of healthy controls. Complete data were collected on 27 of the original 34 cases at 15 months. RESULTS: Compared with normal controls, the patient group had significantly lower absolute and mass related peak oxygen consumption (peak V o(2) (p<0.01)), higher ventilatory equivalent for oxygen (p<0.01), lower oxygen pulse (p<0.01), and a lower oxygen uptake efficiency slope (p<0.01) at 6 months. This impairment was unexpected and out of proportion with the degree of lung function abnormality. Residual high resolution computed tomography of thorax (HRCT) abnormalities were present in 14 patients. Those with abnormal HRCT findings had significantly lower mass related peak V o(2) than subjects with normal radiology (p<0.01). Absolute and mass related peak V o(2) in the patient group remained impaired at 15 months despite normalisation of lung function in all patients. CONCLUSIONS: The mechanism for the reduced aerobic capacity in children following SARS is not fully understood, but it is probably a consequence of impaired perfusion to the lungs at peak exercise and deconditioning.

Radiological and pulmonary function outcomes of children with SARS.

We examined the radiological and pulmonary function outcomes of children affected with severe acute respiratory syndrome (SARS) at 6 months from diagnosis. Twenty-one female and 26 male Chinese patients (median age, 13.6 years; interquartile range, 9.9-16.0) were studied. In each subject, high-resolution computed tomography (HRCT) of the thorax and pulmonary function were assessed. All children were asymptomatic and had a normal clinical examination. Mild pulmonary abnormalities were detected on HRCT in 16 (34.0%) subjects, including residual ground-glass opacification (n = 5), air trapping (n = 8), and a combination of ground-glass changes and air trapping (n = 3). The need for oxygen supplementation (P = 0.02) and lymphopenia during the course of illness (P = 0.012) were significant risk factors in predicting abnormal HRCT. There were no significant lung function differences between those with and without HRCT abnormalities. Despite complete clinical resolution, a considerable proportion of children affected with SARS had abnormal HRCT findings at 6 months. These abnormalities were more prevalent in those with severe disease. It is important that careful follow-up be carried out to assess the clinical significance and persistence of such abnormalities.