SARS-CoV-2-related bronchiolitis: a multicentre international study

Background Bronchiolitis is the main acute lower respiratory tract infection in infants. Data regarding SARS-CoV-2-related bronchiolitis are limited.Objective To describe the main clinical characteristics of infants with SARS-CoV-2-related bronchiolitis in comparison with infants with bronchiolitis associated with other viruses.Setting, patients, interventions A multicentre retrospective study was conducted in 22 paediatric emergency departments (PED) in Europe and Israel. Infants diagnosed with bronchiolitis, who had a test for SARS-CoV-2 and were kept in clinical observation in the PED or admitted to hospital from 1 May 2021 to 28 February 2022 were considered eligible for participation. Demographic and clinical data, diagnostic tests, treatments and outcomes were collected.Main outcome measures The main outcome was the need for respiratory support in infants testing positive for SARS-CoV-2 compared with infants testing negative.Results 2004 infants with bronchiolitis were enrolled. Of these, 95 (4.7%) tested positive for SARS-CoV-2. Median age, gender, weight, history of prematurity and presence of comorbidities did not differ between the SARS-CoV-2-positive and SARS-CoV-2-negative infants. Human metapneumovirus and respiratory syncytial virus were the viruses most frequently detected in the group of infants negative for SARS-CoV-2. Infants testing positive for SARS-CoV-2 received oxygen supplementation less frequently compared with SARS-CoV-2-negative patients, 37 (39%) vs 1076 (56.4%), p=0.001, OR 0.49 (95% CI 0.32 to 0.75). They received less ventilatory support: 12 (12.6%) high flow nasal cannulae vs 468 (24.5%), p=0.01; 1 (1.0%) continuous positive airway pressure vs 125 (6.6%), p=0.03, OR 0.48 (95% CI 0.27 to 0.85).Conclusions SARS-CoV-2 rarely causes bronchiolitis in infants. SARS-CoV-2-related bronchiolitis mostly has a mild clinical course.