The GHS Index also measures domains not explicitly captured in other health security assessment tools, such as health system readiness and preparedness for global catastrophic biological risks (GCBRs). The Johns Hopkins Center for Health Security defines GCBRs as ‘events in which biological agents—whether naturally emerging or reemerging, deliberately created and released or laboratory engineered and escaped—could lead to sudden, extraordinary, widespread disaster beyond the collective capability of national and international governments and the private sector to control.’22 While the JEE’s biosafety and biosecurity indicators are undoubtedly vital metrics of GCBR preparedness, some health system capacities not sufficiently captured in the tool—such as abilities to test, approve and dispense new medical countermeasures—are also essential to GCBR prevention and mitigation. The GHS Index goes above and beyond the JEE in this regard, featuring a dedicated category focusing exclusively on health system capacities required to mitigate epidemic threats. This was the lowest-scoring category across all countries in the GHS Index: 131 countries ranked in the lowest tier of scores, highlighting critical vulnerabilities in global capacities to care for sick patients and protect health workers during public health emergencies, including GCBRs.1 A comprehensive list of GHS Index indicators measuring GCBR preparedness is provided in the inaugural report.1