This is a summary written by members of the CITF Secretariat of Canadian Blood Services’ November 2023 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.

The latest CITF-funded report from Canadian Blood Services suggests that seroprevalence due to infection was 83% in November 2023, up slightly from 81.6% in October 2023. This increase was not statistically significant. Consistent with previous reports, the percentage of younger donors (ages 17-24) who had infection-acquired SARS-CoV-2 antibodies was 92.5% by November 30, 2023, slightly higher than the 91.8% observed in October 2023. Self-declared black, Indigenous, and racialized donors continued to have higher seroprevalence due to infection compared to self-declared white donors.

Key findings:

  • Infection-acquired seroprevalence was 82.97% by November 30th, 2023, up slightly from the 81.62% observed by October 31, 2023. There was a week-to-week variation over November from 83.28% to 82.81% to 82.89% to 82.92%.
  • Consistent with the previous survey, donors aged 17-24 years old continued to have the highest seroprevalence due to infection of all age groups at 92.46% by the end of November, increasing slightly from the 91.79% observed in October 2023.
  • As in previous Canadian Blood Services surveys, self-declared racialized donors continued to have higher infection-acquired seroprevalence (87.73%) compared to self-declared white donors (81.64%). Infection-acquired seroprevalence observed in both populations was similar to what was observed in October 2023 (86.78% vs. 80.15%).
  • Infection-acquired seroprevalence among the most and least materially deprived donors (based on postal code) was similar in November 2023 (82.27% vs. 82.35%). This was consistent with what was observed in October (82.03% vs. 82.27%).
  • All blood donors had antibodies against the spike protein, indicating active immune responses due to either vaccination or infection. Interestingly, those who tested positive for antibodies against the nucleocapsid protein continued to have higher concentrations of spike antibodies compared to those who only had spike antibodies.


The latest report builds on the October 2023 report and includes samples from 32,035 unique donors over the age of 17 who donated blood between November 1 and November 30, 2023, across Canada, excluding Quebec and the Territories.

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.