Comparative analysis of pediatric Respiratory Syncytial Virus epidemiology and clinical severity before and during the COVID-19 pandemic in British Columbia, Canada

Background: The COVID-19 pandemic affected Respiratory Syncytial Virus (RSV) circulation and surveillance, causing logistical complexity for health systems. Our objective was to describe changes in epidemiology and clinical severity of RSV cases in British Columbia (BC), Canada. Methods: Comparative analysis of RSV detections in children <36 months at BC Children's Hospital (BCCH) between September 1 and August 31 of 2017-18, 2018-19, 2019-20, 2020-21 and 2021-22. Results: About one-fifth of children tested RSV positive on average across all periods. The median age of RSV cases was 11.8 [IQR: 3.8 to 22.3] months in 2021-22 versus 6.3 [IQR: 1.9 to 16.7] months in 2017-20 (p<0.001). Increased testing in 2021-22 (n=3,120) compared to 2017-20 (average n=1,222) detected milder infections with lower proportion hospitalized in all age subgroups <6 (26.0%), 6-11 (12.3%), 12-23 (12.2%) and 24-35 (16.0%) months versus 2017-20 (49.3%, 53.5%, 62.6%, 57.5%, respectively) (all p<0.001). Children <6 months consistently comprised most hospitalizations and those born prematurely <29 weeks or with chronic respiratory co-morbidities remained at highest hospitalization risk in 2021-22. Among hospitalized cases, intensive care, respiratory support or supplemental oxygen use did not differ between the 2017-20 and 2021-22 periods. Conclusions: RSV circulation halted during the pandemic, but with the lifting of mitigation measures a subsequent resurgence in children <36 months of age was accompanied by shift toward older (24-35 month) cases in 2021-22, without increased severity. For the 2022-23 season, increased circulation and residual vulnerability in additional birth cohorts spared from RSV infection during the pandemic could have marked cumulative healthcare impact, even with the same proportion hospitalized.

[1]  S. V. van Haren,et al.  Implications of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Pandemic on the Epidemiology of Pediatric Respiratory Syncytial Virus Infection , 2022, Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America.

[2]  S. Madhi,et al.  Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis , 2022, The Lancet.

[3]  F. García-Muñoz Rodrigo,et al.  Effects of public health measures during the SARS-CoV-2 pandemic on the winter respiratory syncytial virus epidemic: An interrupted time series analysis. , 2022, Paediatric and perinatal epidemiology.

[4]  M. Jit,et al.  Determinants of RSV epidemiology following suppression through pandemic contact restrictions , 2021, Epidemics.

[5]  A. Elliot,et al.  The Epidemiology of Respiratory Syncytial Virus in Children Under Five Years-Old During the COVID-19 Pandemic Measured by Laboratory, Clinical and Syndromic Surveillance in England: A Retrospective Observational Study Including the 2020/21 Winter Season , 2022, SSRN Electronic Journal.

[6]  E. Shapiro,et al.  Estimation of the Timing and Intensity of Reemergence of Respiratory Syncytial Virus Following the COVID-19 Pandemic in the US , 2021, JAMA network open.

[7]  S. Mukhi,et al.  Seasonality of Respiratory Viruses at Northern Latitudes , 2021, JAMA network open.

[8]  S. Tsuzuki,et al.  Resurgence of Respiratory Syncytial Virus Infections during COVID-19 Pandemic, Tokyo, Japan , 2021, Emerging infectious diseases.

[9]  C. Delacourt,et al.  Impact of public health measures on the post-COVID-19 respiratory syncytial virus epidemics in France , 2021, European Journal of Clinical Microbiology & Infectious Diseases.

[10]  Wei Hao Lee,et al.  Examining the interseasonal resurgence of respiratory syncytial virus in Western Australia , 2021, Archives of Disease in Childhood.

[11]  J. Langley,et al.  Potential resurgence of respiratory syncytial virus in Canada , 2021, Canadian Medical Association Journal.

[12]  S. de Lusignan,et al.  Low levels of respiratory syncytial virus activity in Europe during the 2020/21 season: what can we expect in the coming summer and autumn/winter? , 2021, Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin.

[13]  J. Avner,et al.  Delayed Seasonal RSV Surge Observed During the COVID-19 Pandemic , 2021, Pediatrics.

[14]  M. van Boven,et al.  Population-based serology reveals risk factors for RSV infection in children younger than 5 years , 2021, Scientific Reports.

[15]  Sang Woo Park,et al.  The impact of COVID-19 nonpharmaceutical interventions on the future dynamics of endemic infections , 2020, Proceedings of the National Academy of Sciences.

[16]  C. Sikazwe,et al.  The impact of COVID-19 public health measures on detections of influenza and respiratory syncytial virus in children during the 2020 Australian winter , 2020, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[17]  P. Klenerman,et al.  Humoral and cellular immunity to RSV in infants, children and adults. , 2018, Vaccine.

[18]  K. Ishii,et al.  Age-Specific Profiles of Antibody Responses against Respiratory Syncytial Virus Infection , 2017, EBioMedicine.

[19]  S. Turvey,et al.  Outcomes of Respiratory Syncytial Virus Immunoprophylaxis in Infants Using an Abbreviated Dosing Regimen of Palivizumab. , 2016, JAMA pediatrics.

[20]  Eneida A. Mendonça,et al.  Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis , 2014, Pediatrics.