Supplementary file 1_Healthcare system disruption across WHO-declared PHEICs: a 4S comparative case analysis.docx

Two reviewers independently assigned indicator-level codes, with disagreements resolved by consensus; indicators classified as Not Reported were combined with Not Activated. Activated indicators were summed within domains (range 0–3), and each observed configuration was assigned to one of four profiles using a fixed hierarchical rule sequence.</p>Results<p>All eight events activated at least one indicator, and external workforce mobilization (S1) and diagnostic bottleneck (T3) were documented in every event.

COVID-19 was the only event activating all 12 indicators (systemic convergence). The two Ebola virus disease events shared an identical configuration of complete Staff, Stuff, and Systems activation with Space limited to temporary or repurposed facilities (workforce-cascade). H1N1 influenza, poliomyelitis, and mpox clade I formed the residual partial multi-domain category and did not share a common domain signature.

Zika virus disease and mpox clade II met the limited-domain rule, with no Space-domain activation.</p>Conclusion<p>Public Health Emergencies of International Concern designation was not sufficient to identify a common pattern of documented health-system disruption. The typology is a provisional descriptive partition rather than a severity ranking, causal model, or predictive tool, and its residual category is heterogeneous by construction.

Profiles are conditional on the documentary evidence base and the settings it represents; baseline health-system capacity was not incorporated, so the same pathogen could plausibly yield a different configuration elsewhere. The framework may offer a common vocabulary for discussing domain-specific preparedness needs under the revised International Health Regulations and the developing WHO Pandemic Agreement, but external validation is required.</p>