Research is essential in improving health outcomes and discovering new ways to treat and prevent various diseases. In serological research studies, we collect and analyze blood serum to detect antibodies, antigens, or other disease markers. This is useful in determining the disease status in an individual, past exposure to infectious disease pathogens, immune response following vaccination or other disease progression markers. Serological studies are also useful in diagnosing non-infectious diseases such as autoimmune-related conditions, blood and genetic disorders. While blood specimens are routinely collected from patients attending clinics and hospitals, such populations are highly selected and may not be representative of the entire population, and specimen collected from them may not always be adequate to answer population-level research questions. This makes blood specimens collected from the community a valuable resource to public health researchers. However, not everyone is willing to participate in such research, particularly when it involves invasive procedures such as blood draws.
According to the research code of ethics, participation in research and research procedures should be voluntary. A participant has the right not to participate or withdraw consent at any time without providing a reason. Refusal to participate in a given research project may become a major issue if several people turn down participation, potentially leading to a selection bias where recruited participants are not representative of the entire target population. Results from such a may give wrong parameter estimates or may not be sufficient to draw generalizable conclusions. Thus, it is always imperative for researchers to minimize refusals and when they occur try to understand the reasons why potential participants refuse to take part in serological studies.
The Kenya Multisite Integrated Surveillance of SARS-COV-2 and other Pathogens (KEMIS) project, conducted between October 2020 and June 2024, was aimed at estimating the proportion of people who had antibodies against SARS-CoV-2. The study comprised of a series of four cross-sectional surveys within the Nairobi Urban Health and Demographic Surveillance System (NUHDSS) and involved approximately 3400 households drawn from Korogocho and Viwandani informal settlements where APHRC runs the Nairobi Urban Health and Demographic Surveillance System (NUHDSS). Similar surveys were separately conducted in Kilifi and Kisumu. Research activities involved conducting interviews and collecting blood samples from children and adults. These activities were preceded by intense community sensitization through local administration, community mass media and sustained community engagement throughout the survey period.
Overall, we achieved high response rates of 88%, 82%, 87%, and 91% in the four rounds of data collection from random samples selected at different times i.e. March to May 2021, March to June 2022, September to December 2022, and July to October 2023 respectively. While, by many standards, these participation rates in the two communities were impressive, there are valuable lessons to learn from the 12%, 18%, 13% and 9% respectively, of those randomly selected who declined participation citing a variety of reasons. In the section below we discuss, the reasons participants gave for not consenting to providing a blood sample.
Hematophobia
Slightly over half of the participants who declined consent did so for fear of seeing blood, also known as hematophobia. For these individuals the sight of blood makes them feel anxious, uncomfortable, or even panicked. People with hematophobia may faint at the sight of blood, experience nausea, or have severe anxiety.
Fear of pain
For some participants, fear of pain associated with blood draws or other medical procedures posed another substantial barrier to participation. Previous painful experiences, whether from blood draws or unsuccessful attempts, often leave individuals with a strong aversion to similar procedures in the future. Pain can be a deeply personal experience, and the anticipation of it can be just as distressing as the actual event.
Superstitions and mistrust
Superstitions and mistrust around blood collection were other key reasons for declined consent in the KEMIS project. In many communities, cultural and religious beliefs contribute to the perception that blood has spiritual or supernatural significance. Participants often fear that their blood could be used for personal gain or even harm through supernatural means. This fear is sometimes coupled with a deeper mistrust of research purposes and the intentions behind collecting biological samples. As one 49-year-old female participant explained, “I will talk to you, but I’m not comfortable with giving my blood … I worry about how my blood will be used or if it could cause any harm to my family. That’s why I have decided not to participate.” This reflects not only a fear of the physical act of blood collection but also a concern about how the blood might be used, underscoring the role mistrust plays in refusal.
Fear of blood drawing leading to symptoms of reduced blood in the body
The fear of blood drawing, particularly the concern about potential symptoms of reduced blood volume in the body, emerged as a reason for declined consent, especially among parents considering participation for their children. Many parents expressed worries about the physical impact of blood draws, and this fear was compounded by the reality that residents of slum areas may already be facing health challenges due to poor dietary conditions, leading to concerns about the ability to replenish lost blood. Some adults also voiced similar fears, reflecting a broader anxiety about the implications of participating in medical procedures when their health and well-being are already precarious.
Lack of interest in research
Many people do not appreciate the value of participating in research activities. This disinterest can arise from various factors, such as a perceived irrelevance of the research, lack of awareness about its goals, busy personal schedules, or even negative attitudes toward research involving blood sample collection. Individuals may not feel compelled to participate if they do not see how the research personally benefits them or how it impacts public health. Additionally, some people are simply unaware of the research process or misunderstand its purpose.
Parental or guardian refusal for children
As good research practice dictates, in studies involving minors, the consent of a parent or guardian is necessary for participation. Some individuals under 18 years of age did not participate in the KEMIS study because their parents or guardians refused to consent. The refusal was due to several reasons, ranging from safety concerns to the lack of good understanding of the research study.
Even with the knowledge that the invasive procedures used cause minimal harm, some parents or guardians still felt uncomfortable allowing their children to participate in the study. Others also perceived that with blood samples drawn, tests may be conducted beyond what is required for research and were concerned about the use and sharing of their children’s data.
Research fatigue
One more reason for refusal stemmed from research fatigue which manifested as a negative attitude toward the African Population and Health Research Center (APHRC). Participants who have been repeatedly engaged over long periods may become disillusioned with the process since the NUHDSS routinely collects data from the same population. A female participant aged 36 expressed this sentiment, saying, “You APHRC have been asking us the same questions since I was a girl. Now I’m married, and you’re still asking the same things.”
This negativity may not always arise from direct negative experiences with the institution, but rather from a lack of understanding about the broader impact of research on the community. Participants may feel fatigued or disengaged if they perceive the research as repetitive or disconnected from meaningful outcomes. Additionally, some individuals may misunderstand the intent of research organizations, believing that their efforts are driven purely by profit or that the studies will not benefit the community. This misconception can create doubt about the purpose of the research, further discouraging participation.
Cultural, gender and power dynamics in decision-making
In some instances, women require the consent of their husbands or other male figures, such as fathers, before agreeing to participate. This is often the case in patriarchal societies where men are traditionally seen as the decision-makers for the family. While women may consent to participate in research involving non-invasive procedures without seeking permission from their husbands/fathers, studies that involve blood draws are deemed more serious and may require the husband/father to give a green light. As a result, if the husband or father is unavailable or unwilling to provide consent, the woman or child may be unable to participate in the research, even if they are personally willing to do so.
Approaches to overcoming the challenges
To address these issues, we found that a multi-faceted approach works best. First and foremost, clear communication is essential. In KEMIS, we provided participants with detailed explanations about the process of blood collection, including the amount of blood required, the purpose of the study, and the safety measures in place to protect participants. This helped alleviate anxieties about pain or health risks.
Second, creating a supportive environment played a key role. By offering calming techniques, ensuring the presence of experienced healthcare professionals, and allowing participants to voice their concerns openly, we fostered trust and reduced discomfort. In cases where individuals feared the sight of blood (hematophobia), we offered distractions and reassurances to help ease their anxiety.
Another major factor was addressing mistrust and superstitions surrounding blood collection. In some communities, cultural beliefs lead to fears that blood may be used for harmful purposes. To counter this, we worked closely with local leaders and used platforms like community forums and radio to clarify the objectives of the research, emphasizing its public health benefits and the strict ethical guidelines surrounding sample use.
Moreover, alleviating fears about blood loss was crucial, especially for parents concerned about their children’s health. We reassured them by explaining the minimal amount of blood needed to ease their concerns about replenishing lost blood.
Finally, engaging the community was key to tackling disinterest and parental refusal. We involved local leaders and respected individuals in sensitization efforts, which helped demystify the research process and build trust. For parents offering open dialogue where they could ask questions and voice concerns created an environment of transparency and mutual respect.
By integrating these strategies—clear communication, supportive environments, trust-building, addressing fears, and ongoing community engagement—we successfully navigated the various reasons for refusal and achieved high participation rates. Future researchers can adopt similar approaches, ensuring that participants feel respected, informed, and comfortable throughout the research process.
Conclusion
Every research process will likely face different challenges that may affect the timely completion and the integrity of the data. When participants decline to take part in a study, it can be a serious issue, especially when the achieved sample size is not sufficient to allow the drawing of inferences about the larger population. Also important is the risk of particular groups inadvertently being unrepresented in the study sample, a problem we refer to as a selection bias. Biased participation can potentially make findings and conclusions from studies invalid and need to be always guarded against by researchers. The most common reasons highlighted above can be addressed if effective community engagement is held before and during the study. These engagements should involve individuals known to the community and ensure the information about the research is easily accessible and understood by the target population. The KEMIS study team employed these approaches and successfully implemented four survey rounds of the study in the NUHDSS and we believe that these insights can be useful for similar research studies in future.
*Collins Omenda contributed to the drafting of this article.