This is a summary written by members of the CITF Secretariat of Canadian Blood Services’ June 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 the 80% mark in estimated infection-acquired seroprevalence among Canadian adults was reached by June 30, 2023. The report, which summarises results of samples from adult blood donors, found that 80.0% had anti-nucleocapsid antibodies, up very slightly from the 79.6% found by May 31. The percentage of younger donors (ages 17-24) who had infection-acquired seroprevalence surpassed 90% by the end of June. Self-declared Indigenous and racialized donors continued to have higher seroprevalence due to infection than did self-declared white donors.

Key findings:

  • Infection-acquired seroprevalence was 80.0% by June 30, 2023, up only slightly from the 79.6% found by May 30th. There was some week-to-week variation over the course of the month of June from 80.2% to 80.9% to 79.1% to 79.8%.
  • Donors aged 17-24 years old continued to have the highest seroprevalence due to infection among all age groups at 90.2%.
  • As in previous Canadian Blood Services surveys, self-declared racialized donors continued to have higher infection-acquired seroprevalence (85.7%) compared to self-declared white donors (78.4%).
  • The most materially deprived donors (based on postal code) continued to have higher infection-acquired seroprevalence than the least materially deprived individuals (81.9% vs 78.7%), as was seen in May (81.2% vs 78.6%).
  • 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 nucleocapsid protein tended to have higher concentrations of spike antibodies compared to those who only had spike antibodies.

Conclusion

The latest report builds on the May 2023 report and includes samples from 31,790 unique donors over the age of 17 who donated blood between June 1st and June 30th, 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.