Longitudinal Cohort Analysis of Antibody Responses Neutralization Efficiency and Long-Term Immunity in natural SARS-CoV-2 infection, Vaccination and its robustness against emerging Variants of Concern.

The pandemic of SARS-CoV-2 and it's associated disease (COVID-19) has resulted in millions of deaths and deep socioeconomical impact globally. While countries such as Canada are trying to reach a level of vaccine acquired herd immunity many questions remains on SARS-CoV-2 immunity. To answer those questions, 1,000 individuals from the Ottawa/Gatineau region have been recruited and enrolled in a longitudinal cohort study called Stop the Spread Ottawa https://omc.ohri.ca/SSO/ (SSO) for an initial period of 10 months. During this period, saliva samples have been collected to access the presence of the virus as well as monthly blood draw to test the presence of antibodies using our established high-throughput robotic testing lab. A second phase of SSO will continue to track a subset (n=300) for an additional 34 months making SSO one of the largest and longest study of SARS-CoV-2 immunity in Canada. The samples collected within this study are of extreme value due to the fact that contain baseline samples acquired before SARS-CoV-2 infection and most importantly before Vaccination. These rare samples therefore holds precious research opportunities. Some of the question we aim to answer are the following : How long does immunity last after natural infection and vaccination? Are some groups of participants mount less robust immune responses following vaccination which can lead to breakthrough infection? How does natural infection and vaccination protects against emerging variants (VOC)? Is a vaccine strategy more robust and long lasting than others? Furthermore, using this cohort, post-infection sequelae (I.e. long COVID-19, post-COVID syndrome) and the impact of auto-antibodies will be investigated. Critical information about antibody-mediated immunity will be shared with the scientific community and local/regional/national health authorities which will guide public health measures, vaccination strategy (need for booster) and VOC impact in Canada.