Systems in depth
One section per system: its state at evidence close, its exposures and what the operational series will watch.
Contents
- ·Edition home
- ·Executive summary
- 1Health threats cross every line
- 2Key findings
- 3Systems and sectors at baseline
- 4Risks and capability
- 5High-consequence outbreak that overlaps reduced financing and thin surveillance
- 6Readings from the other desks
- 7The 2027 agenda
- 8Systems in depth
- AMethodology
- BData appendix
- CReferences and record
- ·Complete edition, for print
8.1Common causes
One cause can strike many places at once: an animal reservoir, a resistant organism, a broken water system or a vector. The shared cause matters more than the disease.
1 in 6
bacterial infections resistant, 20236
| Instance | Mechanism in action | Evidence | Status |
|---|---|---|---|
| Animal origin | over 60% of emerging diseases reported globally come from animals | 13 | Reported |
| Vector-borne spread | dengue cases reached 14.6 million in 2024, a record for a twelve-month period | 11 | Reported |
| Drug resistance | resistance rose in over 40% of monitored combinations, 2018 to 2023 | 6 | Reported |
| Water and sanitation failure | cholera: 451,499 cases and 7,870 deaths in 47 countries in 2025 | 10 | Reported |
Pathways in this mechanism
- BIO → HLT spillover
- WAT → HLT cholera
- FOO → HLT food safety
Evidence to bind in 2027
- common-cause tagging of outbreaks
- frequency of concurrent causes
Related editions
- GLB Global Systems
- SR-02 Critical Infrastructure and Lifeline Systems
- SR-03 Global Supply Chains, Trade and Chokepoints
- SR-07 Food–Water–Energy Security
- GS-04 Health and One Health
- GS-03 Food and Agrifood Systems
8.2Domino effects
A failure in one place removes protection in the next. Outbreaks cross health zones, provinces and borders, and immunity gaps turn small outbreaks into large ones.
| Instance | Mechanism in action | Evidence | Status |
|---|---|---|---|
| Spread inside a country | seven provinces and 63 of 167 health zones by 27 September 2026 | 47 | Reported |
| Spread across borders | Uganda had 20 confirmed cases and one imported case was reported in France by early July | 2647 | Reported |
| Immunity gaps | 13.5 million zero-dose children; 95,000 measles deaths in 2024 | 89 | Reported |
| Missing countermeasures | no licensed vaccine or specific treatment for Bundibugyo virus | 47 | Reported |
Pathways in this mechanism
- HLT → HLT outbreak spread
- HLT → TRD restrictions
- FIN → HLT response funding
Evidence to bind in 2027
- timing of spread between zones
- health worker infection data
Related editions
- GLB Global Systems
- SR-02 Critical Infrastructure and Lifeline Systems
- SR-03 Global Supply Chains, Trade and Chokepoints
- SR-07 Food–Water–Energy Security
- GS-04 Health and One Health
- GS-03 Food and Agrifood Systems
8.3Inter-systemic feedbacks
Health depends on money and data, and outbreaks press back on both. Lower financing weakens surveillance, and larger outbreaks draw down emergency funds.
| Instance | Mechanism in action | Evidence | Status |
|---|---|---|---|
| Financing to outbreak | aid for health USD 39 billion in 2025, 51% below the 2021 peak | 22 | Reported |
| Outbreak to emergency funding | an additional USD 3.4 million from the WHO Contingency Fund for Emergencies by 20 May 2026, a total of USD 3.9 million | 24 | Reported |
| Funding gap in endemic disease | tuberculosis: USD 22 billion needed a year; USD 4.8 billion domestic and USD 1.1 billion international in low- and middle-income countries | 12 | Reported |
| Surveillance reach | 48% of countries did not report resistance data in 2023 | 6 | Reported |
Pathways in this mechanism
- FIN → HLT financing
- HLT → FIN emergency spending
- DAT → HLT surveillance data
Evidence to bind in 2027
- preparedness financing outside aid
- effect of funding cuts on surveillance
Related editions
- GLB Global Systems
- SR-02 Critical Infrastructure and Lifeline Systems
- SR-03 Global Supply Chains, Trade and Chokepoints
- SR-07 Food–Water–Energy Security
- GS-04 Health and One Health
- GS-03 Food and Agrifood Systems
8.4Shared vulnerabilities
Different threats share the same weak points: missing countermeasures, resistant organisms, thin laboratory oversight and a narrow donor base.
| Instance | Mechanism in action | Evidence | Status |
|---|---|---|---|
| Missing countermeasures | no licensed vaccine or specific treatment for Bundibugyo virus disease | 47 | Reported |
| Common resistance | over 40% of E. coli and over 55% of K. pneumoniae resist third-generation cephalosporins | 6 | Reported |
| High-containment laboratories | 51 operating level-4 laboratories and 18 planned or under construction in a 2023 tracker | 33 | Reported |
| Donor concentration | US financing for health fell 67% in 2025 | 22 | Reported |
Pathways in this mechanism
- HLT → HLT shared tools
- FIN → HLT donor base
- INF ↔ HLT laboratories
Evidence to bind in 2027
- laboratory oversight data
- dependence on a few donors and suppliers
Related editions
- GLB Global Systems
- SR-02 Critical Infrastructure and Lifeline Systems
- SR-03 Global Supply Chains, Trade and Chokepoints
- SR-07 Food–Water–Energy Security
- GS-04 Health and One Health
- GS-03 Food and Agrifood Systems
8.5Thresholds and tipping
A system can absorb stress until a threshold is crossed. Alert levels, outbreak-end rules and resistance targets mark such thresholds for health security.
| Instance | Mechanism in action | Evidence | Status |
|---|---|---|---|
| Pandemic emergency tier | the Director-General found that the Ebola emergency was not a pandemic emergency | 24 | Reported |
| Outbreak end rule | a 42-day countdown after the last patient left care in the 2025 Kasai outbreak | 23 | Reported |
| Emergency exit | the mpox emergency ended on 5 September 2025 after sustained decline | 5 | Reported |
| Resistance target | a 10% cut in bacterial resistance-associated deaths by 2030 | 7 | Reported |
Pathways in this mechanism
- HLT → HLT alert thresholds
- FIN → HLT response funding
- BIO → HLT spillover thresholds
Evidence to bind in 2027
- thresholds for compound outbreaks
- surveillance coverage needed to detect early
Related editions
- GLB Global Systems
- SR-02 Critical Infrastructure and Lifeline Systems
- SR-03 Global Supply Chains, Trade and Chokepoints
- SR-07 Food–Water–Energy Security
- GS-04 Health and One Health
- GS-03 Food and Agrifood Systems
Notes
Numbers are the edition’s reference numbers, so a note reads the same in every chapter. The full list, with every source and its licence, is in Annex C. Annex C, references
- 13WHO (ed.), One Health, fact sheet (Quadripartite; over 60% of emerging infectious diseases reported globally come from animals). World Health Organization, Geneva. Observation year 2025. Accessed 2026-11-03.back
- 11WHO (ed.), Dengue and severe dengue, fact sheet of 21 August 2025 (more than 14.6 million cases in 2024). World Health Organization, Geneva. Observation year 2024. Accessed 2026-11-03.back
- 6WHO (ed.), WHO warns of widespread resistance to common antibiotics worldwide, news release of 13 October 2025 on the Global antibiotic resistance surveillance report 2025 (data year 2023; 104 reporting countries). World Health Organization, Geneva. Observation year 2023. Accessed 2026-11-03.back
- 10WHO (ed.), Cholera, fact sheet (451,499 cases and 7,870 deaths reported from 47 countries in 2025). World Health Organization, Geneva. Observation year 2025. Accessed 2026-11-03.back
- 47ECDC (ed.), Ebola disease outbreak caused by Bundibugyo virus, Democratic Republic of the Congo, update of 30 September 2026 (cases up to 27 September 2026: 8,116 confirmed and 3,924 deaths; seven provinces; 63 of 167 health zones; Uganda 20 confirmed cases). European Centre for Disease Prevention and Control, Stockholm. Observation year 2026. Accessed 2026-11-03.back
- 8WHO (ed.), Immunisation coverage, fact sheet (WUENIC estimates for 2025, released 15 July 2026). World Health Organization, Geneva. Observation year 2025. Accessed 2026-11-03.back
- 26WHO (ed.), Disease Outbreak News 2026-DON612, 3 July 2026 (1,481 confirmed cases and 454 deaths; one imported case in France). World Health Organization, Geneva. Observation year 2026. Accessed 2026-11-03.back
- 9WHO (ed.), Measles, fact sheet (95,000 deaths in 2024; coverage in 2025; page dated 15 July 2026). World Health Organization, Geneva. Observation year 2024. Accessed 2026-11-03.back
- 22IHME (ed.), Financing Global Health 2025, news release of 15 July 2025 (development assistance for health USD 39 billion in 2025; USD 80 billion peak in 2021; US financing down 67%), read through a syndicated release. Institute for Health Metrics and Evaluation, Seattle. Observation year 2025. Accessed 2026-11-03.back
- 12WHO (ed.), Tuberculosis, fact sheet (10.7 million people fell ill and 1.23 million died in 2024; funding figures). World Health Organization, Geneva. Observation year 2024. Accessed 2026-11-03.back
- 24WHO (ed.), WHO Director-General’s opening remarks at the media briefing on Ebola outbreak in DRC and Uganda, 20 May 2026 (Bundibugyo virus; not a pandemic emergency; Contingency Fund for Emergencies). World Health Organization, Geneva. Observation year 2026. Accessed 2026-11-03.back
- 4WHO (ed.), Amended International Health Regulations enter into force, news release of 19 September 2025 (11 of 196 States Parties rejected; pandemic emergency level; National IHR Authorities). World Health Organization, Geneva. Observation year 2025. Accessed 2026-11-03.back
- 33UNVERIFIED, not opened: King’s College London and George Mason University, Global BioLabs Report 2023 (51 operating level-4 laboratories in 27 countries and 18 planned or under construction), taken from search-result summaries; the document text was not readable. Observation year 2023. Accessed 2026-11-03.back
- 23STAT (ed.), Congo’s last Ebola patient is discharged, article of 20 October 2025 (Kasai province outbreak declared 4 September 2025; 64 cases, 43 deaths; 42-day countdown). STAT, Boston. Observation year 2025. Accessed 2026-11-03.back
- 7WHO (ed.), Antimicrobial resistance, fact sheet (more than 4.7 million deaths associated with bacterial resistance in 2021; 10% reduction target by 2030). World Health Organization, Geneva. Observation year 2021. Accessed 2026-11-03.back
- 5WHO (ed.), Fifth meeting of the International Health Regulations (2005) Emergency Committee regarding the upsurge of mpox 2024, statement published 30 October 2025 (Director-General determination of 5 September 2025). World Health Organization, Geneva. Observation year 2025. Accessed 2026-11-03.back