This is a summary written by members of the CITF Secretariat of Canadian Blood Services’ end of November 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.
Among Canadian Blood donors, the infection-acquired seroprevalence continued to rise in the month of November 2022, to 71%, up from 67.4%, at the end of October. This reflects the continued circulation of Omicron subvariants. Young donors (17-24 years of age) continued having the highest seroprevalence (84.6%) compared to all other age groups. These latest results are from Canadian Blood Services.
- infection-acquired seroprevalence showed a modest increase, from 69.9% in the first week of November to 71% by the end of the month.
- As seen in previous surveys, donors aged 17-24 had the highest infection-acquired seroprevalence (84.6%) compared to other age groups, notwithstanding the fact that the seroprevalence rate increased in all age groups compared to October.
- Seroprevalence rates due to infection increased in November compared to October in all provinces, though the increase was not statistically significant in Saskatchewan, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland. This could be due to the low sample size.
- Racialized groups continued to have a higher seroprevalence rate (78.7%) than self-declared white donors (68.6%).
- The most materially deprived populations continued to have higher seroprevalence than the least materially deprived populations: 73.1% versus 69.4%, respectively.
- Spike (vaccine-induced) antibodies were present in 100% of blood donors. Additionally, concentrations of spike antibodies remained high in all age groups. This was predominantly due by vaccination.
The latest report builds on the mid-November 2022 report and includes samples from 31,080 unique donors over the age of 17 who donated blood between November 1st and 30th 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.