This is a summary written by members of the CITF Secretariat of Canadian Blood Services’ end of October 2022 report of data gathered from blood donations. The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

Despite 100% of blood donors having vaccine-induced antibodies, infection-acquired seroprevalence continued to rise by the end of October 2022, to 67.3%, up from 63.2% at the end of September. This reflects the continued circulation of Omicron subvariants. Additionally, young donors (17-24 years of age) had the highest seroprevalence (81.7%) compared to all other age groups, despite having high spike antibody concentrations, indicative of prior vaccination. These latest results are from Canadian Blood Services.

Key findings:

  • There was a modest week-to-week change in infection-acquired seroprevalence during October from 66.4% in the first week to 68.5% in the last week.
  • Seroprevalence rates increased in October compared to September in all provinces. However, the increase was not statistically significant in Manitoba, New Brunswick, Prince Edward Island, and Newfoundland.
  • Racialized groups continued to have a higher seroprevalence rate (75.3%) compared to white donors (65.3%),
  • The most materially deprived populations continued to have higher seroprevalence than the least materially deprived populations– 69.6% vs. 66.0%.
  • Spike (vaccine-induced) antibodies were present in 100% of blood donors with concentrations remaining consistently high, particularly among younger donors.


The latest report builds on the mid-October 2022 report and includes samples from 31,451 unique donors over the age of 17 who donated blood between October 1st and 31st, 2022, in all of Canada, excluding Quebec and the Territories.

It should be noted that individuals who choose to donate blood are generally in good health and are more likely to live in populous urban areas. Percentages were adjusted for test characteristics and population distribution.

Explore our interactive webpage updated every month, featuring the latest aggregated data gathered by the Canadian Blood Services and Héma-Québec on SARS-CoV-2 seroprevalence in Canada.