Scaffolding Problem-Based Learning in Postgraduate Immunology: A Pyramidal Mind-Mapping Approach to Teaching Complex Immune Mechanisms in COVID-19

Problem-based learning (PBL) is an effective strategy for developing higher-order cognitive skills in biomedical education; however, structured exposure is often introduced late in postgraduate immunology curricula, leaving students insufficiently prepared for complex, independent learning tasks. Teaching immunity to COVID-19 presents additional challenges due to the need to integrate innate, adaptive, and cytokine-mediated immune pathways. The objective of this study was to quantitatively evaluate the effect of a pyramidal PBL intervention using structured mind mapping on academic performance, conceptual organization, and learner engagement among postgraduate immunology students. The intervention group (n = 18) replaced a scheduled didactic lecture with an intergroup pyramidal PBL activity involving domain-specific mind mapping, iterative peer and facilitator feedback, and whole-class synthesis, while a comparable control cohort (n = 20) received conventional lecture-based instruction. Knowledge retention was assessed using a delayed summative examination administered two weeks post-intervention, and student perceptions were measured using a structured Likert-scale questionnaire. The intervention group achieved significantly higher examination scores than controls (mean ± SD: 73.5 ± 4.4 vs. 66.2 ± 6.5), with a mean difference of 7.3 percentage points (95% CI: 3.8-10.7; p < 0.001) and a large effect size (Cohen's d = 1.30). Questionnaire findings demonstrated high acceptability and perceived effectiveness, with most participants reporting improved conceptual understanding, communication skills, and engagement with complex immunological content. These findings indicate that pyramidal mind-mapping-based PBL produces educationally meaningful improvements in learning outcomes and supports earlier scaffolding of problem-based learning within postgraduate immunology curricula.