Results from the latest Canadian Blood Services (CBS) / COVID-19 Immunity Task Force (CITF) collaborative nine-province seroprevalence study show that Canada still remains far from herd immunity. The table below presents the estimated seroprevalence rates for Canada and the provinces served by CBS for the periods May-July, October, and November 2020, as well as for January 2021. In Quebec, the serosurvey by Héma-Québec sampled once in 2020 during the first wave.

  Table 1: Rate of antibody detection in Blood Donors in Canada

  Values % (95% confidence Interval) Values % (95% confidence Interval) Values % (95% confidence Interval) Values % (95% confidence Interval)
Dates May-July October November January
Canada 0.70% (0.63-0.77) 0.88% (0.73-1.04) 1.51% (1.31-1.71) 1.99% (1.84-2.15)
British Columbia 0.56% (0.41-0.70) 0.86% (0.50-1.23) 1.51% (1.04-1.97) 1.48% (1.16-1.81)
Alberta 0.48% (0.33-0.62) 0.76% (0.38-1.14) 1.79% (1.24-2.34) 3.41% (2.89-3.94)
Saskatchewan 0.53% (0.23-0.83) 0.17% (0.00-0.59) 4.17% (2.57-5.77) 2.46% (1.59-3.33)
Manitoba 0.59% (0.30-0.88) 2.96% (1.70-4.23) 8.56% (6.51-10.62) 3.92% (2.92-4.93)
Ontario 0.88% (0.78-0.99) 0.87% (0.65-1.08) 0.77% (0.56-0.97) 1.82% (1.61-2.04)
Quebec* 1.06% (0.82-1.30)      
New Brunswick 0.23% (0.00-0.49) 0.17% (0.00-0.66) 0.49% (0.00-1.20) 0.27% (0.00-0.66)
Nova Scotia 0.69% (0.33-1.05) 0.98% (0.11-1.85) 0.19% (0.00-0.65) 0.56% (0.09-1.03)
Prince Edward Island 0.04% (0.00-0.42) 0% 0% 0%
Newfoundland 0.44% (0.04-0.84) 0.06% (0.00-0.52) 0.95% (0.00-2.09) 0.42% (0.00-0.97)

*A Héma-Québec study revealed this seroprevalence in Quebec, with blood samples collected between May 25 and July 9.