Post‐Covid Bronchiolitis Severity: More of an Attitude Shift Than a True Change

We read with interest the work by Boccard et al. [1], particularly their sub-analysis of virological data and the clinical course of respiratory syncytial virus (RSV) infection. However, we believe that some aspects warrant clarification. The article discusses the severity of bronchiolitis in the post-COVID period. The authors suggest that post-COVID bronchiolitis is more severe due to an increased length of hospital stay (LOS) and a higher usage of oxygen therapy. However, these two outcomes may not be directly associated with increased severity but rather with a shift in physician attitudes. In our view, other factors, such as the use of noninvasive or invasive ventilatory support and transfers to intensive care units (ICU), may be more directly related to the severity of bronchiolitis. Notably, in Boccard paper's neither the use of ventilatory support nor ICU admissions changed over time, raising questions about whether bronchiolitis indeed had a more severe clinical course [2]. Furthermore, existing studies indicate that the severity of bronchiolitis in the post-pandemic period is more likely a result of changes in physician behavior rather than an alteration in the disease itself. For instance, Ghirardo et al. [3] demonstrated that since the 2020–2021 winter season, there has been an increase in the use of high-flow nasal cannula (HFNC) and continuous positive air pressure (CPAP) for bronchiolitis, yet this has not coincided with an increase in intubation rates. A recent multicenter study conducted across seven Italian pediatric intensive care units (PICUs) reported an increase in intubation rates in the post-pandemic period; however, these rates varied significantly among centers, while the use of noninvasive respiratory support remained stable. Thus, as the authors suggested, organizational, management, and staffing challenges may have influenced this change in ventilation management [4]. Finally, we recommend that data regarding the increased use of oxygen supplementation be presented with more precision. First, did hospital policies on the use of oxygen evolve over the 5 years of the study? Second, the authors provided aggregate data on oxygen supplementation. Did low flow or high flow oxygen supplementation, or both increased in the post COVID period? In conclusion, we emphasize that LOS and the use of oxygen may not fully correlate with disease severity and urge caution in interpreting this data. Stefania Tonetto: conceptualization, writing – original draft. Egidio Barbi: validation, writing – review and editing. The authors declare no conflicts of interest.