This is a summary, written by members of the CITF Secretariat.
Paramo M. V., Abu-Raya B., Reicherz F., Xu R. Y., Bone J. N., Srigley J. A., Solimano A., Goldfarb D. M., Skowronski D. M., Lavoie P. M. Comparative analysis of pediatric Respiratory Syncytial Virus epidemiology and clinical severity before and during the COVID-19 pandemic in British Columbia, Canada. medRxiv. 2022. DOI: 10.1101/2022.11.18.22282477
The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.
In a preprint, not yet peer-reviewed, CITF-funded researcher Dr. Pascal Lavoie (University of British Columbia) and colleagues found that children in British Columbia have been more vulnerable to respiratory syncytial virus (RSV) following a lull while protective measures were in place at the height of the COVID-19 pandemic. The median age of those infected with RSV was higher in 2020-21, compared to 2017-20, however the cases were not more severe.
- Over the past five years (2017-2022), an average of 22% of children under the age of three who were tested for RSVRespiratory virus testing was performed using nucleic acid amplification tests (NAAT). NAATs can use several methods to amplify nucleic acids and detect the virus, including but not limited to polymerase chain reaction (PCR). in BC were positive each year.
- In 2021-2022, the median age for RSV cases was 11.8 months, compared to a median age of 6.3 months in 2017-2020.
- In 2021-2022, more testing was performed (3,120 tests), compared to the annual average between 2017 and 2020 (1,222 tests).
- Increased testing detected a wider range of infections including mild infections. Thus, a lower proportion of children reported to be infected were hospitalized across all age groups than in previous years. The percentage of children who tested positive for RSV and were hospitalized in 2021-2022 for RSV by age were: 26% of children aged under 6 months, 12% of children aged 6-11 months, 12% of children aged 1-2 years, and 16% of children aged 2-3 years (versus 49%, 54%, 63% and 58%, respectively, over the 2017-2020 period).
- Children under 6 months comprised approximately half of all RSV-related hospitalizations annually, with no difference between the 2021-2022 and 2017-2020 periods.
- In 2017-2020, the two characteristics most associated with RSV-related hospitalization were younger age and being male. This was not the case for 2021-2022.
- In 2021-2022, being born prematurely at less than 29 weeks, and having chronic respiratory conditions were associated with a 4.1- and 4.8-fold higher risk of hospitalization, respectively.
For the 2022-23 season, we can expect further increased RSV circulation. Children born during the pandemic are especially vulnerable. Ongoing systematic RSV surveillance, including monitoring of severe outcomes, is therefore essential to prepare and adjust the capacities of the Canadian healthcare system.
This study relied on the comparison of laboratory-confirmed RSV cases detected in children under 36 months of age at British Columbia Children’s Hospital (BCCH), in Vancouver, between September 1 and August 31 of 2017-18, 2018-19, 2019-20, 2020-21 and 2021-22. BCCH is the main pediatric referral center for children up to 17 years of age in British Columbia.