RE: Enterovirus D68 Respiratory Infections in Vietnamese Children

Dear Editor, the publication on “Clinical Insights and Severity of Enterovirus D68 Respiratory Infections in Vietnamese Children [1]” is hereby discussed. This study is valuable in describing the clinical features and risk of severe respiratory disease in children infected with Enterovirus D68 compared with rhinovirus and other enteroviruses. However, the research methodology has limitations that should be considered. Firstly, the study uses data from a single national surveillance system, Vietnam, which may limit the ability to apply the results in the context of populations in other regions with different epidemic patterns, demographic structures, and healthcare systems. Furthermore, despite a sample size of 1100 patients, only 55 patients had confirmed EVD68 infection, which may limit the statistical power of some comparisons, especially when subcategories are based on comorbidities and asthma.

Another limitation is the use of clinical data from surveillance, which may have data incompleteness or differences in symptom and treatment documentation between healthcare facilities. The study also failed to control for complicating factors that may affect disease severity, such as nutritional status, immune status, vaccination history, or access to healthcare. Additionally, excluding patients with viral coinfections from the analysis, while simplifying interpretation of results, may not accurately reflect the reality of respiratory infections in children, where multiple comorbidities are often clinically present.

Further analysis… The study results indicate that EVD68 is associated with an increased risk of wheezing and pneumonia, although the level of risk varies depending on comorbidity and asthma. The lower incremental risk of wheezing in asthmatic patients compared with nonasthmatic groups may reflect the baseline airway sensitivity of asthmatic patients, who are already prone to wheezing, thus mitigating the additional impact of EVD68 compared with nonasthmatic groups. Furthermore, the similarity in recovery time in the intensive care unit between groups may suggest that although EVD68 increases the risk of severe symptoms, when patients receive advanced care, recovery outcomes may be similar to those of other respiratory viral infections.

Future research directions include multi-country or multi-center studies comparing the pathogenesis of Enterovirus D68 in different epidemiological contexts, as well as the use of larger sample sizes to improve the accuracy of risk estimations in subgroups such as asthmatic patients or those with other comorbidities. Additionally, immunological and virological studies may help explain why EVD68 is more likely to cause severe respiratory symptoms in some children. Long-term follow-up may also help assess the future impact on lung health, such as the development of asthma or postinfectious lung function. This information will be crucial for planning future care and disease surveillance in children.