Grant: Op. Gr: Emer. COVID Res. Gaps/Prior- Dif. Impacts on Hist. Excl/Underserved Pops

We have been studying the impact of SARS-CoV-2 infection and vaccination on immunity among a representative sample of about 20,000 Canadian adults, in the Action to Beat Coronavirus in Canada (Ab-C) study, since early in the pandemic. Ab-C Risk will recruit an additional 1,000 Canadians belonging to higher risk demographic and ethnic groups. The Ab-C cohort was recruited in collaboration with the Angus Reid Institute, which will continue to lead in surveying participants periodically about COVID-related experiences, including infection, clinical signs and symptoms, exposures, PCR testing for the virus (including variants of concern), and vaccination. Ab-C relies on participants to self-collect finger prick blood samples on special paper, and send them to Unity Health for analysis for SARS-CoV-2 antibodies. Three rounds of surveys and blood samples have been completed. A fourth and fifth round, planned into 2022, will include the new Ab-C Risk cohort. The main Ab-C Risk research questions are: 1. What are the levels of SARS-CoV-2 vaccine-induced and natural immunity among VIPs compared with other groups? 2. How does persistence of SARS-CoV-2 antibodies among VIPs compare with other groups? 3. Can we identify age-specific predictors of maintained and declining SARS-CoV-2 antibodies among VIPs compared with others? After each Phase, Ab-C publishes for a professional audience in high-impact journals, and for the public in a variety of forms, including Ab-C newsletters and interviews with the Canadian press. We plan to add video releases to be widely distributed to planners and others working with VIPs. The Ab-C team, from six Canadian research institutions and the Angus Reid Institute, combines experience in large-scale population epidemiology, demography and biostatistics, laboratory science, clinical infectious disease, Indigenous health, health economics and priority setting, health equity, IT, communications, and knowledge translation.