Post-COVID-19 condition in children: epidemiological evidence stratified by acute disease severity.

BACKGROUND: To determine the prevalence of pediatric Post-COVID-19 condition (PPCC), identify risk factors, and assess the quality of life in children with differing severities of acute COVID-19. METHODS: During a prospective longitudinal study with a 1-year follow-up, we compared non-hospitalized (mild) and hospitalized (severe) COVID-19 cases to a negatively tested control group. RESULTS: 579 children were included in this study. Of these, 260 had mild acute disease (median age:8, IQR:6-10), 60 had severe acute disease (median age:1, IQR:0.1-4.0), and 259 tested negative for SARS-CoV-2 (NT) (median age:8, IQR:5-10). At three months, 14.6% of the SARS-CoV-2 positive mild group (RR:6.31 (CI 95%: 2.71-14.67)) and 29.2% of the severe group (RR:12.95 (CI 95%: 5.37-31.23)) reported sequelae, versus 2.3% of the NT group. PPCC prevalence in the mild group decreased from 16.1% at one month to 4.4% at one year. Children with PPCC exhibited lower physical health-related quality of life scores and higher fatigue scores than the NT children. CONCLUSIONS: Severe acute COVID-19 in children leads to a higher PPCC prevalence than in mild cases. PPCC prevalence decreases over time. Risk factors at three months include prior medical history, hospital admission, and persistent fatigue one month after a positive test. IMPACT: We demonstrate children with severe COVID-19 are more likely to develop Post-COVID-19 condition than those with mild or no infections, and highlights the risk factors. Here we have stratified by acute disease severity, prospectively included a negative control group, and have demonstrated the heterogeneity in prevalence when utilizing various recent definitions of post-COVID. Identifying risk factors for pediatric post-COVID and highlighting the heterogeneity in prevalence based on various current definitions for post-COVID should aid in correctly identifying potential pediatric post-COVID cases, aiding in early intervention.

The Impact of Short-Term Exposure to Air Pollution on the Exhaled Breath of Healthy Adults.

Environmental factors, such as air pollution, can affect the composition of exhaled breath, and should be well understood before biomarkers in exhaled breath can be used in clinical practice. Our objective was to investigate whether short-term exposures to air pollution can be detected in the exhaled breath profile of healthy adults. In this study, 20 healthy young adults were exposed 2-4 times to the ambient air near a major airport and two highways. Before and after each 5 h exposure, exhaled breath was analyzed using an electronic nose (eNose) consisting of seven different cross-reactive metal-oxide sensors. The discrimination between pre and post-exposure was investigated with multilevel partial least square discriminant analysis (PLSDA), followed by linear discriminant and receiver operating characteristic (ROC) analysis, for all data (71 visits), and for a training (51 visits) and validation set (20 visits). Using all eNose measurements and the training set, discrimination between pre and post-exposure resulted in an area under the ROC curve of 0.83 (95% CI = 0.76-0.89) and 0.84 (95% CI = 0.75-0.92), whereas it decreased to 0.66 (95% CI = 0.48-0.84) in the validation set. Short-term exposure to high levels of air pollution potentially influences the exhaled breath profiles of healthy adults, however, the effects may be minimal for regular daily exposures.