CHOIR study: Children and Older Teens Immune Response to SARS-CoV-2 in Montreal
With mass vaccination campaigns underway across Canada for 12 years and older, the pandemic has been dramatically altered although important challenges remain. The EnCORE study is a seroprevalence study in schools and daycares in Montreal with funding until December 31, 2021. We propose to continue EnCORE’s core work of seroprevalence monitoring while incorporating immune response measures for a subset of participants. We will continue following EnCORE study participants (n=2,061) for two additional rounds of data collection. The data collection will involve an online questionnaire followed by in-home finger prick blood collection. The blood samples will be analyzed in a laboratory for natural and vaccine-induced immunoglobin G (IgG). Also, we will randomly select 90 participants from 5 to 11 years of age for venous blood draws to further explore cell-mediated immunity (e.g., total antibody levels, neutralization, and T-cell testing). Multivariable statistical analyses will be conducted to estimate the number of children with SARS-CoV-2 antibodies, vaccine coverage, and magnitude of antibody response. This work will positively contribute to existing COVID‑19 research gaps. The seroprevalence estimates will provide a better understanding of the disease dynamics, to identify hotspots and at-risk groups for targeted interventions, until high coverage of COVID‑19 vaccination is obtained in children and in teenagers. Furthermore, having a better understanding of cell-medicated immunity and the potential role of prior immunity to human common coronaviruses, will be a valuable contribution to COVID‑19 immunology, understanding of vaccine responses, need for booster shots, number of doses needed in children, and potentially an explanation of why children are less likely to be seriously sick with COVID-19.