Pediatric RSV-Associated Hospitalizations Before and During the COVID-19 Pandemic
Authors: Bourdeau Malou , Vadlamudi Nirma Khatri , Bastien Nathalie , Embree Joanne , Halperin Scott A. , Jadavji Taj , Kazmi Kescha , Langley Joanne M. , Lebel Marc H. , Le Saux Nicole , Moore Dorothy , Morris Shaun K. , Pernica Jeffrey M. , Robinson Joan , Sadarangani Manish , Bettinger Julie A. , Papenburg Jesse ,   Canadian Immunization Monitoring Program Active (IMPACT) Investigators, Foo Cheryl , Bridger Natalie , Halperin Scott A. , Top Karina A. , Thibeault Roseline , Moore Dorothy , Papenburg Jesse , Lebel Marc H. , Le Saux Nicole , Morris Shaun K. , Kamzi Kescha , Purewal Rupeena , Chawla Rupesh , Jadavji Taj , Burton Catherine , Bettinger Julie A. , Sadarangani Manish , Sauvé Laura , Bullard Jared , Embree Joanne , Pernica Jeffrey 
Published: October 2023

ImportanceRespiratory syncytial virus (RSV) is a leading cause of pediatric hospitalizations.ObjectiveTo describe the epidemiology and burden of RSV-associated hospitalizations among children and adolescents in Canadian tertiary pediatric hospitals from 2017 to 2022, including changes during the COVID-19 pandemic.Design, Setting, and ParticipantsThis cross-sectional study was conducted during 5 RSV seasons (2017-2018 to 2021-2022) at 13 pediatric tertiary care centers from the Canadian Immunization Monitoring Program Active (IMPACT) program. Hospitalized children and adolescents aged 0 to 16 years with laboratory-confirmed RSV infection were included.Main Outcomes and MeasuresThe proportion of all-cause admissions associated with RSV and counts and proportions of RSV hospitalizations with intensive care unit (ICU) admission, prolonged stay (≥7 days), and in-hospital mortality were calculated overall and by season, age group, and region. Seasonality was described using epidemic curves. RSV hospitalizations for 2021-2022 were compared with those in the prepandemic period of 2017-2018 through 2019-2020. Bonferroni corrections were applied to P values to adjust for multiple statistical comparisons.ResultsAmong 11 014 RSV-associated hospitalizations in children and adolescents (6035 hospitalizations among male patients [54.8%]; 5488 hospitalizations among patients aged &amp;lt;6 months [49.8%]), 2594 hospitalizations (23.6%) had admission to the ICU, of which 1576 hospitalizations (60.8%) were among children aged less than 6 months. The median (IQR) hospital stay was 4 (2-6) days. The mean (SD) number of RSV-associated hospitalizations during prepandemic seasons was 2522 (88.8) hospitalizations. There were 58 hospitalizations reported in 2020-2021, followed by 3170 hospitalizations in 2021-2022. The proportion of all-cause hospitalizations associated with RSV increased from a mean of 3.2% (95% CI, 3.1%-3.3%) before the pandemic to 4.5% (95% CI, 4.3%-4.6%) in 2021-2022 (difference, 1.3 percentage points; 95% CI, 1.1-1.5 percentage points; corrected P &amp;lt; .001). A significant increase in RSV-associated hospitalizations was found in 2021-2022 for 3 provinces (difference range, 2.5 percentage points; 95% CI, 1.4-3.6 percentage points for Quebec to 2.9 percentage points; 95% CI, 1.4-3.5 percentage points for Alberta; all corrected P &amp;lt; .001). Age, sex, ICU admission, prolonged length of stay, and case fatality rate did not change in 2021-2022 compared with the prepandemic period. Interregional differences in RSV seasonality were accentuated in 2021-2022, with peaks for 1 province in October, 4 provinces in December, and 3 provinces in April, or May.Conclusions and RelevanceThis study found that the burden of RSV-associated hospitalizations in Canadian pediatric hospitals was substantial, particularly among infants aged less than 6 months, and RSV hospitalizations increased in 2021-2022 compared with the prepandemic period, while severity of illness remained similar. These findings suggest that RSV preventive strategies for infants aged less than 6 months would be associated with decreased RSV disease burden in children.