Influenza and COVID-19 vaccination in Canadian blood donors: A comparison across pre- and post-pandemic periods.

Objective: Seasonal vaccinations reduce donor illness and appointment cancellations and ensure plasma products have antibodies to vaccine-directed strains. We aimed to describe donor influenza and COVID-19 vaccination history and compare this with the general population.

Methods: Two online donor surveys were carried out in 2021 and 2024. Donors were asked about demographics, influenza (2019/2020, 2020/2021 and 2023/2024 seasons) and COVID-19 (ever and 2023/2024 season) vaccination and reasons for vaccination choices. General population vaccination statistics were extracted from public reports. Percentages of donors receiving vaccination were calculated with 95% confidence intervals. Multiple logistic regression models were fitted with demographics as independent variables.

Results: In survey 1, 4582 (30.4% response rate) donors completed a questionnaire; in survey 2, 6376 (21% response rate). More donors under age 65 received the influenza vaccine compared with the general population under age 65 (58% vs. 30% in 2019/2020, 63% vs. 28% in 2023/2024, p < 0.0001) and aged 65+ (81% vs. 70% in 2019/2020, 90% vs. 73% in 2023/2024, p < 0.0001). Fewer donors and the general population received the COVID-19 vaccine in 2023/2024 (under 65 45% vs. 39%; 65+ 76% vs. 67%, p < 0.0001). Most said they were vaccinated to prevent infection and protect others.

Conclusions: Seasonal vaccination rates are higher in older donors, consistent with public health recommendations. Blood donors are more likely to be vaccinated against seasonal influenza than the general population, but post-pandemic uptake of the COVID-19 booster vaccine was low, more similar to the general population.