SARS-CoV-2 and RSV bronchiolitis outcomes

Background: Severe acute respiratory syndrome related coronavirus (SARS-CoV-2) bronchiolitis has arisen with the SARS-CoV-2 pandemic. There is a paucity of literature on SARS-CoV-2 bronchiolitis. Objective: The purpose of our paper was to review and compare outcomes in bronchiolitis due to severe acute respiratory syndrome related coronavirus 2 (SARS- CoV-2) and Respiratory Syncytial Virus (RSV). We also performed a subgroup analysis of two disrupted RSV seasons during the pandemic. Methods: This was a retrospective study from a US TriNetX database from March 1, 2020-January 1, 2023. Propensity matching was utilized for confounders. Results: There was a total of 3,592 patients (1,796 in each group) after propensity matching. There was an increased risk of oxygen saturation <= 95 % (RR=1.50 95 % CI 1.58-1.94, p = 0.002) and ICU admission (RR=1.44 95 % CI 1.06-1.94, p = 0.02) in those with SARS- CoV-2 but not for oxygen saturation <= 90 % (RR=1.03 95 %CI 0.75-1.42, p = 0.85) or intubation (RR=0.73 95 % CI 0.35-1.47, p = 0.37). There was a decreased risk of a patient with SARS- CoV-2 bronchiolitis being hospitalized (RR=0.65 95 % CI 0.57-0.74, p < 0.0001), respiratory rate >= 60 (RR=0.64 95 % CI 0.48-0.88, p < 0.001) or >= 70 (RR=0.64 95 % CI 0.43-0.96, p = 0.03) when compared to RSV bronchiolitis. Specifically examining SARS- CoV-2 versus RSV bronchiolitis during the delayed RSV seasons, during the first season both infections were not severe, but during the second RSV bronchiolitis season, patients infected with RSV had less risk of ICU admission compared to those infected with SARS- CoV-2. Conclusion: SARS- CoV-2 bronchiolitis patients appeared to have more severe outcomes since the risk of ICU admission was higher for these patients. Also, during the second delayed RSV season, SARS- CoV-2 bronchiolitis was more severe than RSV bronchiolitis.