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

Canadian Blood Services data suggest that 73.5% of donors had infection-acquired antibodies by the end of 2022. This was slightly higher than the 71% estimated at the end of November. The seroprevalence rate increased in all age groups in December compared to November. However, the 17-24 age group continued to see the biggest jump, with about 87% seropositivity due to infections.

Key findings:

  • There was a gradual week-to-week increase over the month of December, from 71.6% to 73% to 73.8% to 75.3%.
  • Seroprevalence rates increased in December compared to November in all provinces.
  • Self-declared racialized donors continued to have higher seroprevalence compared with donors identifying as white: 80% of racialized donors had infection-acquired antibodies compared to 72% of white donors.
  • The difference in infection-acquired seroprevalence observed between the most and least materially deprived populations were not statistically significant: seroprevalence was 75.4% among the most deprived and 73.3% among the least.
  • Infection-acquired seroprevalence observed for the most socially deprived populations and the least socially deprived populations was 72.1% and 75%, respectively.
  • Anti-spike antibodies were present in all blood donors. This was predominantly driven by vaccination.

Conclusion

The latest report builds on the mid-December 2022 report and includes samples from 32,698 unique donors over the age of 17 who donated blood between December 1st and 31st across 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.