Flag of the World Health Organization. Image: United States Mission Geneva, licensed under CC BY 2.0.
The International Health Regulations (IHR) are the legal instrument that organizes health cooperation when a public health event no longer fits within one country’s borders. Implementation remains with national governments, which control hospitals, quarantines, laboratories and borders. The IHR role is narrower: they make surveillance and notification to the World Health Organization (WHO) part of a legal circuit, while technical recommendations help governments assess and coordinate responses to international risks.
This design explains why the IHR appear in almost every discussion of international pandemic governance. The COVID-19 emergency showed that a notification rule works when detection, data, technical scrutiny and political incentives point in the same direction. The amendments approved in 2024 tried to respond to that fracture with a new category of "pandemic emergency," greater attention to equity and financing, and national authorities responsible for coordinating domestic implementation of the regulations.
Summary
- The IHR bind States Parties to respond to the international spread of disease through measures proportionate to the public health risk.
- WHO can declare a Public Health Emergency of International Concern, known as a PHEIC, although its temporary recommendations do not replace national decisions.
- The core IHR obligations connect epidemiological surveillance, notification to WHO, official verification and basic capacities in health systems and points of entry.
- The 2024 amendments, in force for most States Parties since September 19, 2025, created the pandemic emergency category and strengthened language on equity, financing and national authorities.
- The 2025 Pandemic Agreement is separate from the IHR. It addresses prevention, production, access and benefit-sharing, and full signature and ratification still depended on completion of the PABS annex.
From Sanitary Regulations to a Global Regime
International health cooperation predates WHO. In the nineteenth century, outbreaks of cholera, plague and yellow fever crossed maritime routes and forced governments to choose between health protection and commercial disruption. The International Sanitary Conference held in Paris in 1851 already dealt with that problem: quarantines protected ports, yet they could also block international traffic without a common standard. The tension between disease control and the movement of people and goods still runs through the regime.
In the twentieth century, cooperation became institutionalized. Sanitary bodies in the Americas, Paris and the League of Nations created routines for epidemiological information and border measures to move in comparable form. After the Second World War, WHO brought this field together in a universal specialized agency. The first international sanitary rules of 1951 were later turned into the International Health Regulations, initially centered on a small number of classic quarantinable diseases.
The 2005 revision changed the logic. Instead of listing only specific diseases, the IHR began to cover "events" that could represent a risk of international spread, whatever their cause or origin. The regulations replaced a closed list with an operational question: can the event affect other states and require coordination? That change gave the IHR flexibility for new pathogens, laboratory accidents, chemical events and situations in which early information is incomplete.
The 2005 regulations entered into force on June 15, 2007. They apply to 196 States Parties, including all WHO members, and bind those governments subject to the rejections or reservations provided by the system itself. Their stated function is to contain the international spread of disease in a way that is proportionate to the public health risk and avoids unnecessary interference with international traffic and trade. That formula limits the regime’s two classic failures: omission in the face of risk and excessive restrictions without sufficient health justification.
How the IHR Work
The IHR operate through a chain of national obligations and international decisions. Each State Party must develop core capacities to detect, assess, notify and respond to public health events. These capacities connect surveillance, laboratories, risk communication and points of entry to one purpose: making the early signal reach the government and WHO before international spread is already consolidated.
The IHR National Focal Point is the permanent channel between the government and WHO. It must be available every day and allow rapid communication when an event may have international relevance. With the 2024 amendments, the text also requires a National IHR Authority, responsible for coordinating domestic implementation of the regulations. The difference matters: the focal point communicates, and the national authority organizes the internal system that makes that communication credible.
Notification to WHO starts before complete scientific certainty. The IHR decision instrument asks states to weigh severity, unusual character, likely international spread and effects on travel or trade. If those criteria point to a possible international impact, the event should be notified. The design reduces the political delay that appears when governments wait for perfect confirmation before acknowledging a risk.
WHO can request verification when it receives information from sources outside the official channel, such as scientific networks, media reports or other governments. This possibility was an important innovation of the 2005 revision. It recognizes that epidemiological information travels through technical and public networks before formal diplomacy receives it. The affected state remains central: it must validate the information received and speed up a shared risk assessment, including when it needs to correct or contextualize the initial report.
PHEIC: the IHR’s Highest Alert
A Public Health Emergency of International Concern, usually called a PHEIC, is the main political trigger of the IHR. It is defined as an extraordinary event that constitutes a public health risk to other states through international spread and may require a coordinated international response. The WHO director-general makes the declaration after assessing available data through scientific principles and the advice of an Emergency Committee.
The Emergency Committee acts as an advisory body. It advises the director-general on whether a PHEIC exists and on temporary recommendations. Those recommendations connect surveillance, public health measures and international movement around one test: the response should be proportionate to risk and supported by a strong epidemiological justification. This function helps harmonize responses and discourages travel or trade restrictions adopted as a political reflex.
The legal limit is decisive. Temporary recommendations guide governments. Decisions on lockdowns, vaccination mandates, borders, national laws and hospitals remain under domestic authority. The IHR create duties of cooperation, information and capacity, and concrete implementation remains with the national authorities that apply public health measures. This distinction became more visible after COVID-19, when domestic controversies began to confuse international coordination with supranational executive authority.
A PHEIC has real weight even with national implementation. It changes ministerial priorities, affects financing flows, guides humanitarian agencies and signals risk to transport and health authorities. The force of the instrument lies less in formal coercion than in its ability to align political attention, technical knowledge and administrative action.
Zika, COVID-19 and the Problem of Trust
Earlier PHEICs show how the IHR combine incomplete science and urgent political decision. During the zika outbreak associated with congenital malformations in 2016, Brazil was at the center of the emergency. WHO convened a committee, declared a PHEIC and worked with Brazilian authorities and institutions such as Fiocruz to investigate the relationship between infection and neurological harms. The episode showed that serious uncertainty about health consequences can also sustain an international emergency, beyond immediate lethality.
COVID-19 exposed a broader problem. WHO declared a PHEIC on January 30, 2020 and characterized the situation as a pandemic in March. Many governments were slow to adjust surveillance, hospitals, stockpiles, public communication and mobility rules. Others adopted broad and poorly coordinated restrictions. The IHR supplied the legal vocabulary for warning and response, and the effectiveness of the alert depended on material capacity, political trust and equitable access to medical products.
That gap explains why the later reform had two fronts. The IHR revision clarified categories, strengthened national authorities and made equity more explicit. The Pandemic Agreement negotiations moved the debate toward prevention, preparedness and access to medical products. The IHR govern the alert and response circuit. The agreement seeks to reorganize part of the political economy that decides who receives technology, inputs and products during a crisis.
The institutional lesson was hard. When the first reporting country receives only reputational cost, silence becomes a rational incentive. When solidarity arrives without financing, the promise loses administrative weight. When the alert meets fragile hospitals and concentrated supply chains, correct information becomes operational frustration. That is why health diplomacy began to treat surveillance, sovereignty, intellectual property, productive capacity and financing as parts of the same problem.
The 2024 Amendments
The 77th World Health Assembly approved a package of IHR amendments on June 1, 2024. For most States Parties, they entered into force on September 19, 2025. The reform preserved the 2005 regulations and adjusted what recent emergencies had exposed: alert categories, national obligations and institutional follow-up mechanisms.
The most visible change was the creation of the "pandemic emergency." It functions as a level of alarm within the universe of PHEICs. The category is reserved for communicable events with a risk of wide geographic spread and impact capable of straining health systems, economies and societies. The intention is to give a legal name to the kind of crisis that requires rapid, equitable and coordinated international mobilization, above a localized emergency.
The amendments strengthened equity language. The text now links core capacities more directly to financing and access to relevant health products. This responds to a central criticism of COVID-19: the same alert produces unequal responses when a few countries concentrate laboratories, purchase contracts, factories and fiscal resources.
Another institutional element was the creation of a Committee of States Parties to facilitate implementation of the regulations and promote cooperation. Its role is to follow IHR implementation, encourage dialogue and help governments apply general obligations in administrative practice. The reform formalized the National IHR Authority for the same reason: domestic coordination requires administrative command that links the technical communication channel to domestic execution.
The entry into force of the amendments followed different calendars in some cases. WHO reported that 11 states rejected the 2024 amendments. In addition, states that had rejected an earlier amendment on deadlines had their own timetable for entry into force. This detail confirms that the IHR are binding and still remain an interstate operational treaty: governments accept common rules, preserve rejection procedures and retain responsibility for implementation.
Relationship with the Pandemic Agreement
The Pandemic Agreement, adopted by the World Health Assembly on May 20, 2025, is a separate instrument from the IHR. It was negotiated after COVID-19 because pandemic preparedness depends on a material base that a legal alert cannot provide by itself. Outbreak prevention needs to be backed by stronger national systems, shared technology and more predictable access to vaccines, diagnostics and therapeutics.
The most sensitive issue is the PABS system, short for pathogen access and benefit-sharing. The logic is to link the sharing of samples and genetic sequences to access to products developed from that sharing. The bridge tries to avoid a recurring asymmetry: countries send information quickly without receiving vaccines or treatments in time. In May 2025, WHO indicated that the agreement would be opened for signature after adoption of the PABS annex, with entry into force after 60 ratifications.
In 2026, negotiation of the PABS annex remained the critical step. World Health Assembly reporting from May 2026 indicated continued work through an intergovernmental group and pointed to the objective of completing the annex for later consideration. The institutional distinction therefore matters: the IHR were already in force. The Pandemic Agreement, by contrast, still depended on additional steps before operating fully.
The sovereignty boundary was made explicit again in this agreement. National laws, vaccination mandates, lockdowns and travel restrictions remain domestic decisions. The clause has a legal and political function: it separates international cooperation from internal command and reduces space for disinformation about WHO powers.
National Implementation and Health Diplomacy
National implementation gives the IHR their concrete force. Each State Party has to connect the international alert channel to its own public-health administration. Large territories, federal structures and major entry points make that task harder when information has to move quickly from clinics and laboratories to political authorities and WHO. The same legal framework produces different administrative tests depending on how each country organizes health authority and emergency response.
The zika emergency illustrates one version of that problem. The PHEIC alert required national institutions to connect scientific investigation, public communication and cooperation with WHO. The episode was a test of global health governance: clinical data about congenital harms had to move through federal coordination and vector research while maternal-child care was already under pressure.
Other states meet the same legal architecture through different bottlenecks. One government may struggle with points of entry, another with laboratory capacity or access to medical products, but all still have to decide how international guidance fits domestic authority over restrictive measures. After COVID-19, debates over the IHR and the pandemic instrument linked national administration to equity, financing and access to health products.
The essential point is administrative. First, surveillance and laboratories have to feed internal information flows. Ports, airports and technical diplomacy then connect those flows to international commitments. Public trust closes the chain because it affects whether guidance becomes practice. When one of these elements fails, the obligation continues to exist, but the concrete response loses speed.
Scope and Limits
Although the IHR are a central element of pandemics as an international security issue, their logic is sanitary, administrative and diplomatic. They seek to anticipate risks, share information, guide proportionate measures and avoid national reactions that worsen the crisis. The security they offer consists of reducing surprise, shortening delay and making national responses minimally compatible.
Their main limit is that they depend on the same governments they seek to coordinate. The problem appears when states delay notifications, underestimate risks or lack laboratories. The same limit appears when governments impose excessive restrictions or compete for medical products instead of coordinating responses. WHO alerts, recommends and convenes. Budgets, productive capacity, social trust and national administrative command remain domestic. The IHR work best when domestic capacity exists and transparency is accompanied by support, without being reduced to reputational punishment.
The 2024 amendments indicate the direction of reform. They give pandemic emergencies a more precise legal category, strengthen national coordination and make equity an explicit part of implementation. The reform further creates institutional space to monitor whether obligations move from treaty text into public administration. Diseases can cross borders quickly, so information must cross them even faster. The response will only be legitimate if it combines urgency, proportionality and fair access to the means of protection.