The world's pandemic-reporting treaty just changed. The US opted out.

A package of amendments to the International Health Regulations — the binding rulebook that governs how countries detect, report and respond to health threats that cross borders — took effect on 19 September 2025, adding a new, higher tier of alarm called a "pandemic emergency" [s1]. The United States is one of the few countries the new text does not bind: it formally rejected the 2024 amendments and remains held only to the treaty's earlier versions [s1].

What the IHR is, and what changed

The IHR (2005) is the legal instrument, adopted by the World Health Assembly, under which states are obliged to build core capacities to spot outbreaks and to notify the World Health Organization of events that may constitute a public health emergency of international concern (PHEIC) — the mechanism behind declarations for COVID-19, mpox and polio. It is the framework that sits beneath the running list of active PHEICs, including the long-running polio emergency.

The Seventy-seventh World Health Assembly adopted the latest package on 1 June 2024 through resolution WHA77.17, amending a long list of articles and adding two entirely new ones [s2][s1]. Under the treaty's own rules, the amendments entered into force on 19 September 2025 for all states except those that rejected or reserved against them [s1].

The main additions

The headline change is a definition. Alongside the existing PHEIC, the amended Article 1 defines a "pandemic emergency" as a PHEIC caused by a communicable disease that has, or risks, wide geographical spread across multiple states; is, or risks, exceeding those states' health-system capacity; is, or risks, causing substantial social and economic disruption, including to international traffic and trade; and requires rapid, equitable and enhanced coordinated international action [s1]. It is a higher rung on the ladder — a signal that an event is not merely an international concern but is behaving like a pandemic — intended to trigger a more urgent, collective response.

The other changes are institutional:

• A National IHR Authority. Each state is to designate an entity to coordinate implementation within its borders, an upgrade from the older "National IHR Focal Point," which was essentially a communications desk [s1].
• A Coordinating Financial Mechanism (new Article 44 bis), meant to promote timely, predictable and sustainable financing for countries to build and maintain the capacities the treaty requires — a direct response to the chronic underfunding of preparedness in lower-income countries [s1].
• A States Parties Committee (new Article 54 bis), a standing, facilitative body to help countries implement the regulations, rather than an enforcement court [s1].
• An equity thread. The amendments define "relevant health products" — medicines, vaccines, diagnostics, medical devices and more — needed to respond to emergencies including pandemic emergencies, language aimed at the access gaps that defined the COVID-19 response [s1].

The US opted out

The official record is unambiguous. The consolidated IHR text lists the United States among the states party with a "Rejection" recorded against the 2024 amendments; it remains bound by the regulations as they stood after the 2014 and 2022 amendments, not the 2024 version [s1]. In practical terms, the new "pandemic emergency" tier and the new committee and financing structures are not obligations the US has accepted.

What it does and doesn't mean

It is worth being precise, because the IHR has been the subject of heavy misinformation. The amendments do not give WHO power to impose lockdowns, mandate vaccination, or override national law; the regulations set reporting duties and coordination structures, and WHO's core tools remain recommendations, not commands [s1]. The "pandemic emergency" definition changes what gets declared and how urgently, not who is in charge inside a country.

What the amendments cannot fix by themselves is the gap between text and practice. The Financial Mechanism and the States Parties Committee are attempts to address the two failures the pandemic exposed most starkly — money and follow-through — but both are new and untested, and neither compels a state to act. Their force will depend on whether wealthy countries fund the mechanism and whether the committee develops real influence.

The US position adds a further strain. A system built substantially around American surveillance, financing and laboratory capacity now has its largest historical contributor formally outside its newest provisions, against a wider backdrop of retreating global health financing. That runs in parallel to the separate, still-unfinished negotiations over a pandemic agreement and its access-and-benefit-sharing terms, which the same 2024 assembly set in motion [s2].

What to watch

Whether the Coordinating Financial Mechanism attracts real money, how the first invocation of a "pandemic emergency" plays out in practice, and whether the US rejection hardens into a lasting split in the global health-security system or is revisited by a future administration.