Vaccine‐incentivized blood donation: A survey of public perceptions in Canada

Canadian blood donations declined during the start of the COVID‐19 pandemic. Conversely, vaccine demand outpaced supply during the initial stages of the COVID‐19 vaccine rollout in Canada. This study investigates public perceptions regarding vaccine‐incentivized blood donation, among COVID‐19 and future pandemics, in Canada.


INTRODUCTION Blood donation products
Only 4% of Canadians regularly donate blood products even though approximately 52% say they or their family members have needed blood products for medical or surgical treatment, and an estimated 47.7% of Canadians are eligible donors [1,2]. In Canada, blood donations are tightly regulated by Héma-Québec (www.hema-quebec. qc.ca) in the province of Quebec and by Canadian Blood Services (www.blood.ca) everywhere else. Canadians may begin donating blood at age 18 in Quebec and age 17 across the rest of Canada [3,4]. Various safeguards and protocols exist to regulate blood product quality and donor safety including health-related factors that preclude some Canadians from donating blood. These factors include sexual history, body weight and haemoglobin levels.
The start of the COVID-19 pandemic widened the gap between blood product supply and demand. In particular, blood transfusion use rose among COVID-19 patients and amplified pre-pandemic blood product requirements [5]. Many COVID-19 patients with acute respiratory distress syndrome required the provision of extracorporeal membrane oxygenation services, frequently necessitating blood transfusions-2-5 units of packed red blood cells and 3-9 units of platelet concentrate daily for haemoglobin maintenance and haemostasis [6].

COVID-19 vaccinations
There was a global shortage of COVID-19 vaccinations in the first 2 years of this pandemic [11]. Equitable COVID-19 vaccine distribution remains an area of debate [12]. Canadian provinces and territories used individualized prioritization strategies with eligibility largely based on age, health risk factors and likelihood of COVID-19 exposure [13]. However, despite the high demand for blood products within hospitals and for vaccines among the general public during the third wave of the COVID-19 pandemic, blood donors were not prioritized for vaccination.
To our knowledge, no study has investigated public perception on prioritized vaccine access for blood donation. We set out to determine the Canadian public's perception of the acceptability of using vaccine prioritization as a strategy to increase blood donation.

Survey design
A working group (K.S., L.A.E. and K.T.) constructed a 19-question, electronic survey in English, assessing perceptions on COVID-19 vaccineincentivized blood donation (Appendix S1). Participants were asked demographic questions, whether they would donate blood to be vaccinated ahead of others in their respective cohort(s) during the COVID-19 and/or future pandemics, and to rank their position on two statements using a five-point Likert scale with answers ranging from 'strongly disagree' to 'strongly agree'. An optional short-answer question encouraged personal comments and concerns with this proposal. The general public (i.e., non-HCP) was defined as individuals aged 17-65 who are not frontline healthcare workers or long-term care home residents. The survey targeted all people living in Canada aged 17 and older but also allowed for non-Canadian recruitment. Institutional ethics approval was obtained from the University of Toronto Health Sciences Research Ethics Board.

Survey dissemination
A target sample size of 665 participants was determined using a sample size calculator (www.calculator.net) with a confidence level of 99%, a margin of error of 5% and an estimated Canadian population size of 38,250,000 with 47.7% as eligible donors. The survey was administered through the Google Forms Web-based platform (Google, Mountain View, CA, USA) for a period of 6 weeks from June to July 2021 during the third wave of the COVID-19 pandemic in Canada. The survey was distributed in person with authors encouraging civilians in the metropolitan cities of Toronto, Montreal, Vancouver, London and Niagara to physically scan QR codes that redirected them to the survey. The questionnaire was also distributed broadly online with authors posting survey links via social media platforms including Facebook, Instagram and Twitter. There were no participation incentives.
Participants were asked to complete the survey only once; respondent names were not collected to maintain anonymity. Participation was voluntary and informed consent was obtained for all respondents.

Statistical analysis
Data were analysed using descriptive statistics. All statistical analyses were performed using Microsoft Excel (Microsoft, Redmond, WA, USA).
Statistical significance, with Bonferroni correction for four tests, was set at p < 0.0125. The survey included mandatory and optional questions but could only be submitted if all mandatory questions were answered.
Survey responses were analysed cumulatively and divided categorically based on demographic factors, blood donor status, donating during the pandemic and healthcare setting status. Blood donor status was dependent on the respondent having ever donated blood even if currently ineligible. Healthcare setting status (i.e., HCP) was dependent on the respondent currently being a healthcare worker or working or living in a healthcare institution such as hospitals and long-term care homes. All optional short-answer question responses were read and prominent themes were addressed.
A randomized resampling of the overall results was performed to determine if observed patterns were maintained when responses were categorized proportionally to better reflect the Canadian population. Randomization categories were donation during pandemic, donor eligibility, location, age, sex and race. All respondent answers were assigned a random number, using Microsoft Excel algorithms, within each sub-category (e.g., locations of Alberta, Ontario and Quebec).

Respondent demographics
A total of 787 respondents participated with representation from all sexes, ages, races, locations of residence within Canada and work T A B L E 1 Demographic composition of survey responses.  Figure 2 and Table 2), whereas HCP respondents were more likely to be fully vaccinated at the time of being surveyed than non-HCP (95% vs. 84%, respectively), no participants felt they would be required to wait more than 6 months to receive their second dose of the COVID-19 primary vaccination series ( Figure S1).

Blood donors versus non-donors
Among all respondents, 511 (65%) participants were currently eligible to donate blood products, 247 (31%) had donated blood on at least one occasion and 48 (6%) had donated blood since the beginning of COVID-19 lockdowns ( Figure 1).

Category randomization
Category randomization was performed to demonstrate the generalizability of the overall patterns once corrected to reflect the Canadian demographic population ( Table 3). The patterns for the percentage of

DISCUSSION
This survey considered Canadian's thoughts on vaccine-incentivized blood donation. The focus was within each participant's vaccine allocation cohort such that, for example, a healthy 50-year-old patient who donates blood products would be compared with another healthy 50-year-old patient who does not. We report that many Canadian demographic groups positively viewed incentivized vaccination, particularly more positively than ineligible donors did.

COVID-19 vaccinations
Canada effectively used province-and territory-specific, multi-tiered, prioritization systems to domestically distribute its purchased supply of vaccines [13]. However, this distribution was not without its hic- vaccinations.
Previous studies have investigated the positive and negative effects of incentivized blood donation. Remuneration incentivization benefits included increased recruitment of first-time donors and overall blood donation rates [23]. Evidence from nearly 14,000 American Red Cross blood drives demonstrated a positive effect on participation that was even more pronounced as the economic value of incentives increased [24]. Non-remuneration strategies have also been successful. A recent field experiment used a registry of volunteer donors to increase donations during critical shortage episodes, highlighting the effectiveness of crowding-in in volunteers with purely altruistic motives and those with a preference for commitment [25].
However, research has also demonstrated the detrimental effects of soft incentivization on blood donation. Social recognition has been shown to be less effective when offered to citizens who prioritize altruism over image motivation [26,27].
The World Health Organization has repeatedly recommended against incentivized blood donation; however, whether economic incentives positively or negatively impact blood donation has remained a subject of debate [24,28]. Vaccination was a primary concern for Canadians during and following the third wave of the  People have been found to donate blood more than once after they have completed their first donation and become familiar with the process and its positive impact on society [28]. Our study similarly demonstrated that previous blood donors were statistically significantly more likely to consider donating blood for prioritized vaccines compared with respondents that had never previously donated. This finding suggests that vaccine-incentivized blood donation may bring back recurrent blood donors. In the interim, it is evident that more work must be done to appeal to those who have not yet donated.
Public vaccination sites, where Canadians queued for hours during the third and fourth waves of COVID-19, may present as great locations to educate the public on the process and impact of their blood donations.

Concerns regarding blood donation for vaccine prioritization
It has been hypothesized that paying blood donors would be economically inefficient due to diminished blood quality [30]. Many of our survey respondents feared that incentives would entice high-risk individuals to donate blood in an unsafe manner. During the COVID-19 pandemic, the most relevant risk would be blood-borne infections, active COVID-19 and baseline anaemia. However, research analysing nearly 100,000 donors has demonstrated that economic incentives can have positive effects on blood donations without creating adverse selection in the safety and usability of donated products [24].
Although the literature is limited, research has also demonstrated the benefit of non-monetary incentivization over financial options [30,31]. Notably, incentivized vaccination would only allow respondents a single non-monetary vaccine reward that they would nonetheless be eligible to receive thereby theoretically being less attractive to risky blood donation.
Importantly, the Canadian healthcare system is built upon principles of universality and accessibility [24]. A common theme among survey respondents was inequitable donor eligibility leading to disparities in vaccine distribution, particularly among men who have sex with men. Some respondents were concerned about the stigmatization that could ensue from such restrictive vaccine prioritization policies. Fortunately, in September 2022 Canadian Blood Services removed criteria specific to men and implemented broad, high-risk, sexual behaviour-based screening for all donors, regardless of gender or sexual orientation [32]. However, this nevertheless remains a discriminatory barrier, particularly among people who may wish to donate blood products but are excluded due to their sexual practices.
An incentivized donation policy could diminish Canadian's trust in the medical system through thoughts of a discriminatory 'two-tiered' approach against ineligible blood donors.
Furthermore, our study also highlighted concerns that the same barriers preventing certain populations from accessing vaccines and blood donations may be reflected in those who could access this theoretical incentive. Canadian blood donors likely mimic American donors who are, on average, White and in their 40s [33]. In contrast, we know that racialized Canadians were the most impacted by the pandemic [34]. This calls for strong interdisciplinary educational efforts and policies to ensure this non-monetary incentive would be an asset to the healthcare system rather than a burden on those already marginalized by the pandemic.
Allocating a portion of vaccines for incentives also reduces gen-

Conclusion
There is a marked imbalance between eligible Canadian blood donors and those who donate blood products. We surveyed the Canadian general population during the third wave of the COVID-19 pandemic on their sentiments towards a theoretical policy of providing cohortspecific vaccine-based incentives for blood donation as a solution to rising demands of blood products and vaccinations during the COVID-19 and future pandemics. We report that respondents were more likely to appreciate vaccine-incentivized blood donation policies compared with ineligible donors. Further research is needed to determine whether such attitudes would translate to increased blood donations and, if they do, to determine the tools and resources required to effectively and equitably establish such an incentivized structure while ensuring it is as accessible as, if not more than, vaccination sites to mitigate any geographic or socioeconomic disparities that may arise. Critical analysis of distribution and management would be needed to avoid disadvantaging those who are ineligible to donate blood or have religious or personal concerns. As well, it would be critical to ensure that Canadians do not feel coerced into donating blood.
Ideally, future studies will trial vaccine-based incentive approaches to determine patterns in blood donations. Overall, this comprehensive study will likely prove beneficial in re-opening the conversation about the dearth of blood donors in Canada.