Applying a Small Procedure Prior to Injection/Vaccination Reduces Pain in Children

In this proposed study, we aim to apply a minor procedure prior to a treatment that induces pain (e.g., injection / vaccination) to help manage pediatric pain.

The proposed study builds on the well-known placebo effect, which occurs when individuals experience improvements in their conditions (e.g., pain relief) after using an inert substance (e.g., a placebo analgesic). This effect is primarily attributed to expectations about the placebo's effectiveness. We extend this line of research by demonstrating that, under certain circumstances, merely possessing a placebo can also lead to pain relief. This possession-based placebo analgesic effect arises from a sense of ownership, which enhances expectation that the owned placebo can provide benefits to the self. In this study, we will expand the scope of the possession-based placebo effect by examining its applicability in a real-life situation - we expect that by providing children an ownership of a first-aid bandage before their vaccination will improve their pain experiences.

Focusing on children's pain is critical for several reasons. First, pain is a common experience for children, who are often less mature and independent than adults in assessing and managing it. This makes them a vulnerable population that requires improved pain management interventions. Unfortunately, pain recognition and treatment in children are still inadequate (Birnie et al., 2014). Second, most past placebo analgesic studies have focused on adults, leading to significant knowledge gaps regarding its implications for children (Weimer et al., 2013). This knowledge gap is attributed to historical ethical and legal ambiguities that hindered randomized controlled trials involving children, resulting in their exclusion from research (Yan \& Munir, 2004). Third, research targeting children is essential to understand their unique circumstances and deliver appropriate benefits (Dresser, 1996). The U.S.

Department of Health and Human Services and the Food and Drug Administration (2001) have emphasized the need to broaden research participation among children. A recent motion by the Hong Kong Legislative Council on "Promoting the Development of Children's Healthcare Services" (2024) further highlights this commitment. Finally, age-related factors may influence individual's pain outcomes or responses. Children are more susceptible to the placebo effect than adults (Park et al., 2022), this may be due to the stronger influence of parental (compared to professional) expectations on children's pain perceptions (Gniß et al., 2020). Thus, caution is needed when generalizing adult findings to children (Weimer et al., 2013). Investigating the pain in children is crucial for developing tailored interventions for the pediatric population. This project could let healthcare practitioners and physicians learn about the possibility of tailoring, forming, or optimizing their medical intervention strategies to enhance positive pain outcomes and novel pain management. For instance, practitioners, clinicians, and dentists could consider tailoring their therapeutic interaction and treatment by incorporating an appropriate possession procedure to reduce undesired negative pain outcomes.