Reference:
Iriarte, I., & Phoenix, S. (2021). Understanding relative risk reduction (RRR) and absolute risk reduction (ARR) in vaccine trials. PANDA. https://www.pandata.org/understanding-relative-risk-reduction-and-absolute-risk-reduction-in-vaccine-trials/
Summary:
The article discusses the critical distinctions between Relative Risk Reduction (RRR) and Absolute Risk Reduction (ARR) in the context of vaccine trials, particularly those for COVID-19. RRR compares the efficacy of one intervention against another without considering the overall probability of outcomes, potentially misleading the interpretation of results. In contrast, ARR provides a clearer picture by measuring the actual difference in risk between groups, which is crucial for evaluating the real-world impact of medical interventions. The authors illustrate these concepts through examples, such as the Pfizer vaccine trial, where RRR was reported at 95%, yet ARR revealed a modest reduction in risk. They caution against over-reliance on RRR, advocating for a comprehensive understanding of both metrics to inform public health decisions effectively. The article concludes that while RRR and ARR are essential indicators of vaccine efficacy, their interpretation must consider broader epidemiological contexts and individual risk factors.