This is a summary written by members of the CITF Secretariat of Canadian Blood Services’ mid-February 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.
In its latest CITF-funded seroprevalence report, Canadian Blood Services suggest that 77.3% of blood donors had infection-acquired antibodies by mid-February. This estimate was similar to the 76.7% estimate recorded in January 2023. The youngest donors, aged 17 to 24, continued to have higher seropositivity due to infection compared to other age groups. Self-declared racialized donors continued to have higher seroprevalence due to infection than white donors.
- There was no statistically significant change over the 14-day reporting period from the last week in January (78.52%) to the first week in February (78.34%) and the second week of February (77.31%).
- Continuing the trend of the past few months, donors aged 17-24 years had the highest seroprevalence rate (86.8%) compared to other age groups in the second week of February. Seroprevalence due to infection in other age groups was: 25-39 – 83.7%; 40-59 – 78.5%; and 60+ – 66%.
- Self-declared racialized groups continued to have higher seroprevalence compared to self-declared white donors- 83.3% vs 75.7% in the week of February 8-14.
- The difference in infection-acquired seroprevalence observed between the most and least materially deprived populations closed to around 2.5%; seroprevalence was 79% among the most deprived and 76.4% among the least by mid-February.
- Anti-spike antibodies were present in all blood donors. This may be related to a combination of vaccination and breakthrough infections. Anti-spike concentrations, indicative of vaccination, have increased since the summer of 2022, however, in January, they started to decline, particularly in older age groups, which maybe due to waning. The same trends continue through February.
The latest report builds on the January 2023 report and includes samples from 15,445 unique donors over the age of 17 who donated blood between February 1st and February 14th, 2023, 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.