Likelihood, two years: 2Unlikely; to end-2028
Likelihood, ten years: 3Possible; to end-2036
Systemic impact: 4Severe; global
National impact: 4Severe; typical highly exposed nation
Onset pace: Weeks
Duration (acute phase): 1 year (acute phase; further waves in the second year)
Warning time: Days (international spread precedes reliable detection)
Scope: Global
Recovery horizon: Years
Capability load: Hard 1/3Soft 3/3Economic 2/3; domains loaded High
Concurrency: Standalone; triggers 5 · triggered by 4
Confidence · movement: medium; new

Rated at Standard Severe. Event reach: global event (Rated for a pathogen that meets every Standard Severe condition together. A milder pandemic is more likely than these bands indicate.). Source of scores: model-panel-v0.5.

Load test: results by nation

03Narrative

Dateline: March 2031

The first clusters of severe pneumonia were reported in late September 2029. By the time a reliable diagnostic test was in general use in mid-October, the virus had been sequenced from patients in 34 countries on five continents. Containment at the border was no longer available to any government. Early estimates put the infection fatality ratio at 0.5 per cent and the estimate held through the winter.

Hospitals in the first affected cities reached the limit of their staffed beds in week six. At the national peaks, demand for hospital care ran at twice staffed capacity in the most exposed nations. The binding constraint was staff, then oxygen. Beds and equipment could be added in weeks; trained nurses could not, and 15 per cent of the workforce was absent at the peak through illness, isolation or care for dependants. Health ministries adopted allocation rules for intensive care that most had drafted and few had exercised. Elective surgery, cancer screening and routine immunisation were suspended for months. Maternity services were kept open by redeploying staff from other wards.

More than 20 governments restricted exports of protective equipment, medicines and vaccine inputs within the first two months. Nations with regional manufacturing and advance purchase agreements received their first vaccine deliveries in month five, in quantities sufficient only for health workers. Supply at scale began in June 2030, nine months after the first reports, and reached most low-income nations in 2031.

Absence spread from hospitals to food distribution, freight, water treatment and power operations. No essential network failed outright, but most ran on reduced rosters and deferred maintenance. Schools closed for four months on average, and pupils without a device or a connection at home did not return at the same rate as others. Global output fell 4 per cent in 2030. Governments borrowed to support incomes, and several that had entered the pandemic with high debt and low reserves sought emergency lending within the year.

Public communication determined how long measures held. Where authorities published their data, stated what was unknown and explained allocation decisions, compliance lasted through the second wave. Where guidance changed without explanation, or contradicted what hospital staff were saying in public, false claims about the origin of the virus and the safety of the vaccine reached a majority of adults and vaccine uptake stalled below 60 per cent.

By the end of the first year about 30 per cent of the world's population had been infected and more than 12 million people had died. The nations with the smallest losses were not those with the most hospital beds in their plans. They were those that could staff the beds, keep ordinary care and essential production running and retain public belief in what the authorities said.

The dateline is illustrative, not a forecast. The narrative is hypothetical; the historical anchors below are real events.

04Summary

A novel respiratory pathogen spreads internationally before reliable detection and containment. It infects 30 per cent of the population during the first year, with an infection fatality ratio of 0.5 per cent before effective countermeasures, implying deaths of about 0.15 per cent of the population. Peak hospital demand reaches twice available staffed capacity in highly exposed nations. Effective vaccines are unavailable at scale for nine months and workplace absence reaches 15 per cent at the peak. Governments must sustain ordinary care, essential production and credible communication while allocating scarce treatment. The scenario tests staffed health capacity, access to countermeasures and public trust, not bed counts or written plans.

05Historical anchors

Event	Date	What happened	Calibrates
COVID-19	2020–2022	WHO declared a pandemic on 11 March 2020. Global GDP fell by about 3 per cent in 2020 and WHO estimated 14.9 million excess deaths across 2020 and 2021. Hospitals in the first affected regions exceeded intensive care capacity within weeks. By April 2020 the WTO counted about 80 countries and customs territories restricting exports of medical goods. The first vaccines were authorised in December 2020, about 11 months after the genome was published.	The Standard Severe path: onset in weeks, hospital overload, export restrictions and a vaccine interval of about a year. This scenario assumes a higher infection share and more deaths in the first year.
1918 influenza	1918–1919	An H1N1 influenza virus infected an estimated one third of the world's population in successive waves. Deaths are commonly put at about 50 million, with published estimates ranging widely, and mortality was unusually high among adults aged 20 to 40. No vaccine or antiviral treatment existed.	The upper bound. The infection share matches the 30 per cent assumed here; the fatality ratio was several times higher, which sets Standard Extreme.
Vaccine export restrictions	2021	India suspended most exports of COVID-19 vaccines from late March 2021 during its second wave, interrupting supply to COVAX, which had relied on the Serum Institute of India for a large share of its early doses. The European Union introduced an export authorisation mechanism in January 2021 and Italy used it in March 2021 to block a shipment of about 250,000 doses to Australia. COVAX delivered fewer than half of the 2 billion doses it had targeted for 2021.	The order of access to countermeasures. Producers serve domestic demand first, so nations without manufacturing wait beyond the nine months assumed here.
Exercise Cygnus	October 2016	A three-day UK government exercise simulated the peak of an influenza pandemic. Its report concluded that the UK's plans, policies and capability were not sufficient to cope with the demands of a severe pandemic, and identified surge capacity in health and social care as a weakness. The report was not published until 2020.	The gap between written plans and staffed capacity, and the cost of leaving exercise findings unaddressed and undisclosed.
H5N1 in US dairy cattle	2024–2025	Highly pathogenic avian influenza H5N1 was confirmed in US dairy cattle in March 2024 and spread to herds in more than a dozen states. Dozens of human cases followed, mostly among farm workers, and the first US death was reported in January 2025. No sustained human-to-human transmission was detected.	The warning signal behind the likelihood bands: a virus with pandemic potential circulating in mammals in close contact with people, under uneven surveillance.
Lloyd's human pandemic scenario	December 2024	Lloyd's modelled a human pandemic with a five-year probability-weighted global loss of US$13.6 trillion and a loss of up to 6.4 per cent of global GDP in its extreme variant.	Systemic impact. Level 4 lies between the weighted estimate and the extreme variant.

06Parameters

Shown at their preset values. Parameters are not adjustable in this release and nothing on this page is computed from them. Custom settings run (Phase B) but are labelled 'non-standard run' and excluded from comparisons.

Common variables at Standard Severe · read-only

1. Severity: major
severe (Standard Severe)
extreme
2. Duration (acute phase): 30 days
90 days
1 year (Standard Severe)
3 years
5 years
Standard Severe: 1 year (acute phase; further waves in the second year)
3. Onset pace: days
weeks (Standard Severe)
months
years
4. Warning time: none
days (Standard Severe)
months
Standard Severe: days (international spread precedes reliable detection)
5. Scope: national
regional
global (Standard Severe)
6. Origin: natural (Standard Severe)
accidental
adversarial (great power / neighbour / non-state)
negotiated
7. External support: full
partial
none (Standard Severe)
Standard Severe: none (every nation is affected at once)
8. Concurrency: standalone (Standard Severe)
plus one named scenario
plus two
9. Policy response assumed: none (pure exposure)
current plans executed (Standard Severe)
best practice
10. Recovery horizon: months
years (Standard Severe)
structural

Scenario-specific parameters · read-only

Parameter	Default	Range or options	Note
Population infected in the first year	30 per cent	15 to 50	With the fatality ratio this gives first-year deaths of about 0.15 per cent of the population.
Infection fatality ratio before effective countermeasures	0.5 per cent	0.1 to 2.5	A population average. The age profile is not specified.
Peak hospital demand relative to staffed capacity	2 times	1.2 to 4	Applies to highly exposed nations. Staffed capacity counts beds with the trained staff to operate them.
Time to effective vaccine at scale	9 months	3 to 24	Measured from first reports to supply sufficient for general use in producing nations. Nations without manufacturing or purchase agreements wait longer.
Peak workplace absence	15 per cent	8 to 30	Illness, isolation and care for dependants combined.
Duration of school closure	4 months	1 to 10	A GINC assumption used for the education channel. The panel did not specify it.
Basic reproduction number	2.5	1.5 to 5	Carried from the first-pass record. Consistent with 30 per cent infected in the first year only where measures and behaviour reduce transmission.

07Transmission channels

1
A novel respiratory pathogen spreads internationally through air travel before a reliable diagnostic test is in general use, so containment at the border fails.
2
Infections reach 30 per cent of the population in the first year. Hospital demand rises to twice staffed capacity and treatment is allocated by rule.
3
Ordinary care is displaced: elective treatment, screening, maternity services and routine immunisation are reduced, adding deaths and illness beyond those caused by the pathogen.
4
Workplace absence peaks at 15 per cent, reducing rosters in health, food distribution, freight, utilities and public administration.
5
Producer governments restrict exports of protective equipment, medicines and vaccine inputs. Nations without regional manufacturing or purchase agreements wait longest.
6
Schools and contact-intensive businesses close. Output and tax receipts fall and governments borrow to support incomes.
7
Unexplained changes in guidance and false health claims reduce compliance and vaccine uptake, which lengthens the acute phase.
8
After vaccines arrive at scale from month nine, losses persist in learning, treatment backlogs, long-term illness, public debt and trust.

08Capability loading

High: capability band shifts expected under current plans. Medium: band shifts under 'none' policy response only. Low: strain without band shift. Loads are judgement-based until the Atlas connects. Domains link to the Atlas.

Domain	Load	Channel
Hard
Defence and security	Medium	Military medical, logistics and engineering support to civil authorities; reduced force readiness through illness; biosecurity assessment.
Strategic infrastructure	Medium	Essential networks run on reduced rosters; hospital estate, oxygen supply and digital capacity face peak demand.
Critical technology	High	Diagnostics, genomic surveillance, vaccine platforms and therapeutics manufacturing determine the time to countermeasures.
Soft
Government effectiveness	High	Crisis command, procurement, treatment allocation rules, data publication and continuity of ordinary public services.
Human capital	High	Hospital demand at twice staffed capacity; deaths, long-term illness, displaced ordinary care and lost schooling.
Influence and cohesion	High	Credibility of official communication, compliance with measures, false health claims and international cooperation on supply.
Economic
Macro-financial	High	Output loss, falling revenue, income support and higher sovereign borrowing; funding stress for states with weak buffers.
Industry, trade and supply	High	Export restrictions on medical goods, concentrated pharmaceutical inputs, freight disruption and labour shortage in production.
Energy and resources	Low	Demand falls with mobility; operators maintain supply on reduced rosters.

09Stakeholders

Government: Exposure
Staffed hospital capacity, access to countermeasures, continuity of essential services and the credibility of official communication.
Actions
Plan surge on the staff available, not on bed counts, and exercise treatment allocation rules before they are needed
Secure countermeasure supply through regional manufacturing, advance purchase agreements and stocks of oxygen and protective equipment
Publish data and state what is unknown from the first week, with one accountable source of public health guidance
Watch
WHO Disease Outbreak News and declarations under the International Health Regulations
Occupancy of staffed beds and absence among health workers
Export restrictions on medical goods and vaccine inputs
Technology: Exposure
Operation of digital infrastructure at 15 per cent absence, demand for remote work and learning, exchange of health data and the spread of false health claims on platforms.
Actions
Test continuity of network and data centre operations at 15 per cent staff absence
Make surveillance, laboratory and hospital data systems interoperable before an outbreak
Agree with health authorities how verified guidance is carried and how false health claims are handled
Watch
Time taken to share genomic sequences on public databases
Network load and outage reports during restrictions
Circulation of false claims about vaccines and treatments
Investors: Exposure
Sovereign debt of nations with weak fiscal buffers, travel and hospitality, commercial property, life and health insurance and supply chains for medical goods.
Actions
Run portfolios against a 12-month pandemic with 15 per cent peak absence and no vaccine at scale for nine months
Assess sovereign exposure by fiscal headroom and reserve cover, not by pre-event health rankings
Check portfolio companies for dependence on single-source pharmaceutical inputs and for tested absence plans
Watch
Sovereign spreads and requests for IMF emergency financing
Vaccine trial results and manufacturing capacity announcements
Mobility and workplace absence data
Public: Exposure
Health, access to ordinary care, income, schooling and care for dependants. Exposure is highest for older people, people with chronic illness and households without savings or connectivity.
Actions
Keep a household plan for illness, isolation and the care of dependants
Follow official health guidance and check claims against published data
Local government and civil society should identify in advance the people who will need food, medicines and learning support delivered
Watch
Official guidance and pressure on local hospitals
School closure and reopening decisions
Vaccine eligibility and delivery schedules

10Regional exposure

Region	Exposure	Rationale
North America	High	High air connectivity and chronic illness prevalence; a strong countermeasure industry is offset by low trust in health authorities and fragmented delivery.
Europe	High	Old populations, dense travel links and health workforce shortages; staffed capacity is exceeded early in the first affected cities.
China	High	Dense cities and a large older population; strong manufacturing and control capacity, with a high economic cost from prolonged restrictions.
Indo-Pacific	High	Dense trade and travel hubs; several states have strong outbreak response, while island and lower-income members depend on imported countermeasures.
South Asia	High	Dense populations with limited staffed beds and oxygen supply; a large vaccine manufacturing base that is subject to export restriction.
Gulf and Middle East	Medium	Young populations and fiscal resources in the Gulf; exposure through migrant worker housing, mass gatherings and conflict-affected health systems.
Africa	High	The fewest health workers per head and late vaccine access; young populations lower fatality, but ordinary care and immunisation are displaced.
Latin America and Caribbean	High	Large informal workforces cannot isolate without income; unequal access to care and limited fiscal room for prolonged support.
Russia and Eurasia	High	Older populations with high chronic illness, uneven regional health capacity and low vaccine confidence.

11Early-warning indicators

Indicator	Source	Threshold
Outbreak notifications and public health emergency declarations	WHO Disease Outbreak News	Sustained human-to-human transmission of a novel respiratory pathogen reported in two or more WHO regions
Avian and swine influenza in mammals and human spillover cases (Includes H5N1 herd and human case counts.)	World Organisation for Animal Health (WAHIS) and WHO	Clusters of human cases with no recorded animal contact
Time from sample collection to public release of genomic sequences	GISAID	—
Density of doctors, nurses and midwives	WHO Global Health Observatory (National Health Workforce Accounts)	Below 44.5 per 10,000 population, the WHO reference density
Core capacity scores under the International Health Regulations (COVID-19 outcomes did not follow pre-event capacity rankings; read with trust and workforce measures.)	WHO States Parties Self-Assessment Annual Reporting and Joint External Evaluations	—
Vaccine manufacturing capacity by region	WHO Global Vaccine Market Report	—
Export restrictions on medical goods and vaccine inputs	WTO trade monitoring reports and Global Trade Alert	New restrictions by three or more major producers within one month
Public trust in government and health authorities	Wellcome Global Monitor and OECD Survey on Drivers of Trust in Public Institutions	—

12Compounds

Triggers: S02 Global funding seizure · Output loss and emergency borrowing reprice sovereign debt where buffers are weak.
S05 Legitimacy rupture · Contested emergency measures and postponed votes weaken the lawful authority of governments.
S01 Trade bloc rupture · Export restrictions on medical goods harden into lasting trade barriers.
S11 Debt service reset · A pandemic prompted the 2020 suspension of debt service and could prompt a deeper treatment
S18 Public service leap · Emergency transfers during a pandemic force a state to build delivery systems
Triggered by: S03 Regional war spillover · War and displacement remove surveillance and care, so an emerging pathogen spreads before detection.
S05 Legitimacy rupture · A state without effective government detects and reports an outbreak late.
S06 Breadbasket failure · Food scarcity raises vulnerability to infection and increases contact with wildlife and livestock.
S17 Automated discovery step · Only if dual-use access controls fail; a tail risk, not the central case
Amplified by: S04 Hybrid coercion · Power and telecommunications loss during peak hospital demand; hostile information operations against health guidance.
S07 Core disaster · A disaster in the economic core removes hospital capacity and forces crowded shelter.
Amplifying trends: Pathogen emergence pressureHealth workforce scarcityHealth system demand imbalancePharmaceutical input concentrationConspiracy movements & science denialGlobal health governancePublic communication in crisis
Key trends: Global health governanceCritical Health workforce scarcityVery high Health system demand imbalanceVery high Adaptable vaccine platformsVery high Pathogen emergence pressureVery high
From GINC Trends: the trends rated Very high or Critical for this scenario, of 250. All S10 trend scores.

13Rating rationale

Rating	Band or level	Why
Likelihood, two years	2Unlikely	The full definition was last met in 1918 and COVID-19 came close: one clear case and one near case in a century. The event requires three conditions together: international spread before reliable detection, a fatality ratio of 0.5 per cent and no vaccine at scale for nine months. Faster sequencing and adaptable vaccine platforms make that combination less frequent than pandemics in general. All three panel members placed it at 0.2 to 1 per cent.
Likelihood, ten years	3Possible	Five influenza or coronavirus pandemics have occurred since 1918. Only the first clearly met this infection share and fatality ratio together, with COVID-19 close. Applying the joint conditions over ten years gives 1 to 5 per cent. Circulation of H5N1 in mammals and rising contact between people, livestock and wildlife argue for the upper end of the band. Two panel members rated the event Possible and one Likely.
Systemic impact	4Severe	COVID-19 reduced global GDP by about 3 per cent in 2020 against forecast growth above 3 per cent, and losses persisted. Lloyd's puts the five-year weighted loss from a human pandemic at US$13.6 trillion and its extreme variant at up to 6.4 per cent of global GDP. A pathogen with more first-year deaths than COVID-19 and 15 per cent peak absence falls between the two, at 2.5 to 5 per cent of five-year global output.
National impact	4Severe	In a highly exposed nation about 0.15 per cent of the population dies in the first year and hospital demand reaches twice staffed capacity, so ordinary care is rationed for months. Human welfare and essential services both reach Severe. The rating stops short of Catastrophic because the acute phase is bounded at about a year, physical assets are undamaged and most capability returns within years once vaccines are available at scale.
Confidence	medium	The epidemiological parameters are bounded by 1918 and COVID-19. The likelihood bands depend on how the joint conditions are counted, and one panel member rated both impacts a level higher.

Source of scores: model-panel-v0.5. Confidence refers to the rating, not the scenario. Calibration sources are listed with the anchors above and on the scenario methodology page.

14Open questions

Contested assumptions for the panel to resolve.

Whether the two-year band should be Possible: counting COVID-19 as a full instance of the definition would give an annual rate near 2 per cent, above the range the panel adopted.
Whether the fatality ratio of 0.5 per cent should carry an age profile, since the same average places different loads on ageing and young nations.
Whether an accidental or deliberate release should be a separate scenario, since origin changes warning, attribution and the security response.
How this record should be read with S20, which tests a comparable outbreak met by shared surveillance and a vaccine within 100 days.

15Commentary

No signed commentary in this build.

16Version and citation

Version: 0.5.0 · active · severe-pandemic
Change log: 0.5.0 · 9 October 2026 · Rebuilt in the second pass from Pandemic with a novel pathogen: infection share, fatality ratio, hospital demand, vaccine interval and absence fixed as parameters; likelihood and impact each lowered one band; border closure removed from the definition.
Full change log

Rating history

One row per edition. Each edition page is frozen at release; corrections are published as errata.

Edition	Rank	L2y	L10y	Systemic	National	Confidence	Edition view
2027	7	2Unlikely	3Possible	4Severe	4Severe	medium	Open

Versions

Version	Date	Change
0.5.0	9 October 2026	Rebuilt in the second pass from Pandemic with a novel pathogen: infection share, fatality ratio, hospital demand, vaccine interval and absence fixed as parameters; likelihood and impact each lowered one band; border closure removed from the definition.

Citation and downloads

Cite as

GINC (2027). Scenario S10 A novel respiratory pathogen exceeds health surge capacity, Scenario Library v0.5. scenarios.ginc.org/scenarios/severe-pandemic

Content and data are published under CC BY 4.0.

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