Background and objective: The clinical relevance of the detection of multiple respiratory viruses in acute bronchiolitis (AB) has not been established. Our goal was to evaluate the effect of viral coinfections on the progression and severity of AB.
Methods: A retrospective observational study was conducted in a tertiary hospital in Spain from September 2012 to March 2020. Infants admitted for AB with at least one respiratory virus identified by molecular diagnostic techniques were included. A comparison was made between single-virus infections and viral coinfections. The evolution and severity of AB were determined based on the days of hospitalization and admission to the pediatric intensive care unit (PICU).
Results: Four hundred forty-five patients were included (58.4% male). The median weight was 5.2 kg (IQR 4.2-6.5), and the median age was 2.5 months (IQR 1.4-4.6). A total of 105 patients (23.6%) were admitted to the PICU. Respiratory syncytial virus (RSV) was the most frequent etiological agent (77.1%). A single virus was detected in 270 patients (60.7%), and viral coinfections were detected in 175 (39.3%), of which 126 (28.3%) had two viruses and 49 (11%) had three or more viruses. Hospital length of stay (LOS) increased in proportion to the number of viruses detected, with a median of 6 days (IQR 4-8) for single infections, 7 days (IQR 4-9) for coinfections with two viruses and 8 days (IQR 5-11) for coinfections with ≥ 3 viruses (p = 0.003). The adjusted Cox regression model showed that the detection of ≥ 3 viruses was an independent risk factor for a longer hospital LOS (HR 0.568, 95% CI 0.410-0.785). No significant association was observed between viral coinfections and the need for PICU admission (OR 1.151; 95% CI 0.737-1.797).
Conclusions: Viral coinfections modified the natural history of AB, prolonging the hospital LOS in proportion to the number of viruses detected without increasing the need for admission to the PICU.
What is KnownThe main etiological agent of acute bronchiolitis (AB) is respiratory syncytial virus (RSV); however, other viruses are frequently detected. All viruses may be the sole etiological cause or may occur in association, and a high prevalence of viral coinfection has been described.To date, there are conflicting results on the role of viral coinfections in the severity of bronchiolitis.What is NewViral coinfections influence the progression of AB. The simultaneous detection of 3 or more respiratory viruses is a risk factor for longer hospital stay.The presence of viral coinfections does not condition a greater need for admission to the PICU.
Keywords: Acute bronchiolitis; Length of stay; Pediatric intensive care unit.; Severity; Viral coinfection.
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