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

According to Canadian Blood Services, the infection-acquired antibody rate increased moderately from 65.4% in the last week of September to 66.3% by mid-October, consistent with the continued circulation of Omicron subvariants. Seroprevalence due to infection surpassed 80% among young donors (17-24 years of age) and 70% among the most materially deprived.

Key findings:

  • There was a slight increase in infection-acquired seroprevalence over the 15-day reporting period, from 65.4% in the last week of September to 66.3% by mid-October.
  • Donors aged 17-24 had the highest infection-acquired seroprevalence rate compared to other age groups, climbing to 81.1%, in the week of October 8-15. Seroprevalence in the other age groups was – 25-39: 74.8%, 40-59: 68.6%, and 60+: 50.1% in the same timeframe.
  • Most materially deprived population continued to have higher seroprevalence when compared to the least materially deprived populations– 72.2% vs 64.6% in the week of October 1-7, to 70.8% vs 63.9% in the week of October 8-15.
  • Racialized groups continued to have higher infection-acquired seroprevalence compared with white donors: 70.5% vs. 64.6% in the week of October 1-7, and 73.3% vs. 63.9% during October 8-15.Compared to the last week of September, the infection-acquired seroprevalence rate increased in all provinces except Saskatchewan, Manitoba, New Brunswick, and Prince Edward Island where few samples were tested.
  • Spike antibodies, suggesting vaccination, were present in 100% of blood donors. Spike antibody concentrations have remained consistently high, particularly among younger donors.


The latest report builds on the September 2022 report and includes samples from 15,612 unique donors over the age of 17 who donated blood between October 1st and 15th, 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.