| Autor: |
Charland K; Centre for Public Health Research, University of Montreal, Montreal, QC, Canada., Pierce L; Centre for Public Health Research, University of Montreal, Montreal, QC, Canada., Saucier A; Centre for Public Health Research, University of Montreal, Montreal, QC, Canada., Hamelin MÈ; Research Centre of Quebec-Université Laval, Quebec City, QC, Canada., Barbosa Da Torre M; Centre for Public Health Research, University of Montreal, Montreal, QC, Canada., Carbonneau J; Research Centre of Quebec-Université Laval, Quebec City, QC, Canada., Nguyen CT; Ministère de la santé et des services sociaux, Quebec City, QC, Canada., De Serres G; National Institute of Public Health of Quebec, Quebec City, QC, Canada., Papenburg J; Montreal Children's Hospital of the McGill University Health Centre, Montreal, QC, Canada., Boivin G; Research Centre of Quebec-Université Laval, Quebec City, QC, Canada., Quach C; Departments of Microbiology, Infectious Diseases & Immunology and of Pediatrics, University of Montreal, Montreal, QC, Canada., Zinszer K; Centre for Public Health Research, University of Montreal, Montreal, QC, Canada. |
| Abstrakt: |
Since early 2022, routine testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) based on symptoms and exposure history has largely ceased in Canada. Consequently, seroprevalence studies, particularly longitudinal studies, have become critical for monitoring the rate of incident SARS-CoV-2 infections and the proportion of the population with evidence of immunity. EnCORE is a longitudinal SARS-CoV-2 seroprevalence study comprising five rounds of serology testing from October 2020 to June 2023, in a sample of 2- to 17-year-olds (at baseline), recruited from daycares and schools in four neighbourhoods of Montreal, Canada. We report on SARS-CoV-2 incidence and seroprevalence among the 509 participants in the fifth and final round of the study. Seroprevalence of antibodies from either infection or vaccination was 98% (95 per cent confidence interval [CI]: 97, 99). The infection-acquired seroprevalence was 78% (95% CI: 73-82), and the incidence rate was 113 per 100 person-years (95% CI: 94-132), compared to the seroprevalence of 58% and the incidence rate of 133 per 100 person-years, respectively, in the fourth round of testing (mid-late 2022). Of the 131 participants newly seropositive for infection in Round 4, only 18 were seronegative for infection in Round 5 (median follow-up: 326 days). |
