Researchers moved at an incredibly fast pace to develop vaccines against the SARS-CoV-2 virus, and within a year of the World Health Organization declaring the pandemic, nearly 200 million vaccine doses had been distributed worldwide. The global demand for vaccines, however, meant that some countries, including Canada, opted to extend the time between doses beyond vaccine manufacturers’ recommendations. 

The Objective

Our study seeks to evaluate the level of protection individuals have after two doses of SARS-CoV-2 vaccines with this extended dosing schedule. Additionally, the study seeks to determine how a previous exposure to common cold viruses affect individual’s response to SARS-CoV-2 vaccines and why some individuals do not develop adequate protection (non-responders) even when receiving vaccines on a recommended schedule. These results will help increase our understanding of the factors that contribute to overall vaccine immune response in Canadians and may provide new avenues to improve vaccine efficacy in non-responders. 

Who is participating? 

Participants include a group of healthcare workers in British Columbia and builds on data being collected in two other CITF-funded studies: one which follows paramedics in British Columbia and Ontario (CORSIP), the other which follows teachers in British Columbia (BCCHR Tracking COVID-19 for Safer Schools). 

What does the study involve? 

By analyzing participant blood samples, our team is producing comparative data on the immune response and protection resulting from vaccine schedules by measuring participant’s antibody levels at 2 and 4 weeks after each vaccine dose, as well as 3 and 12 months post-vaccination. 

Our study will also evaluate if an individual’s pre-existing T cells or antibodies against SARS-CoV-2 and other common circulating coronaviruses (cCoVs), have an effect on COVID-19 vaccine immune response.