Effect of Delayed SARS-CoV-2 Vaccine Dose Interval on B Cell Maturation and Antibody Development

The research currently being done is looking at how a delayed dose interval of a SARS-CoV-2 mRNA vaccine impacts the maturation of B cells and the antibodies that those B cells produce compared to antibodies and B cells from participants with a shorter dose interval. During the early days of the SARS-CoV-2 pandemic, Canada implemented a dose sparing strategy with their vaccines, by which the dose interval was extended from 3-4 weeks, to 9-10 weeks. This decision was met with criticism from other countries and institutions with claims of a lack of research into how a delayed dose interval would benefit Canadians. Now that the vaccine program is nearly in its third year, enough time has passed for an in-depth look as to why a delayed dose interval may be more beneficial than a standard dose interval. Participants with either a long or standard dose interval have had blood taken from before their first SAR-CoV-2 mRNA vaccine, and then after each subsequent dose. The peripheral blood mononuclear cells are isolated and frozen for further study. These cells are thawed and stained with fluorescent probes to detect B cell phenotypes. The levels of mature B cells and their subsets can then be compared between delayed and standard dose intervals of vaccination. Some cells from each time-point are separated before the staining and activated to turn into antibody-secreting plasma cells, and those antibodies are used to determine the neutralization capabilities of different SARS-CoV-2 variants using an MSD immunoassay.