This is a summary written by members of the CITF Secretariat of Canadian Blood Services’ December 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 82.68% in December 2023, in line with the 82.97% found in November 2023. Consistent with previous reports, the percentage of younger donors (ages 17-24) who had infection-acquired seroprevalence was the highest of all donor age groups. It was 92.01% by December 31st, 2023, down very slightly from 92.46% at the end of November 2023. Self-declared Black, Indigenous, and racialized donors continued to have higher seroprevalence due to infection than self-declared white donors.

Key findings:

  • Infection-acquired seroprevalence by December 31st, 2023, was 82.68%, similar to the 82.97% observed by November 30th, 2023. There was a week-to-week variation over December from 81.92% to 82.83% to 82.76% to 83.22%.
  • Consistent with the previous survey, donors who were 17-24 years old continued to have the highest seroprevalence due to infection of all age groups at 92.01% by the end of December, similar to the 92.46% observed in November 2023.
  • As in previous surveys, self-declared racialized donors continued to have higher infection-acquired seroprevalence (87.19%) than self-declared white donors (81.47%). Infection-acquired seroprevalence observed in both populations was similar to what was observed in November 2023 (87.73% vs. 81.64%).
  • Infection-acquired seroprevalence among the most and least materially deprived donors (based on postal code of residence) was similar in December 2023 (82.72% vs. 82.75%), consistent with what was observed in November (82.27% vs. 82.35%).
  • All blood donors had antibodies against the spike protein, indicating that all donors have active immune responses due to either vaccination or infection. Interestingly, those who tested positive for antibodies against the infection-acquired nucleocapsid protein continued to have higher concentrations of spike antibodies compared to those who only had spike antibodies.

Conclusion

The latest report builds on the November 2023 report and includes samples from 31,962 unique donors over the age of 17 who donated blood between December 1 and December 31, 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.