Is America on the brink of sparking a new flu pandemic?

**Lead**

A growing chorus of public health experts and former officials is asking whether the United States, through a combination of policy drift, funding cuts and fragmented surveillance, is inadvertently laying the groundwork for a new influenza pandemic. The question is not merely academic for the United Kingdom, which relies heavily on international early-warning systems and vaccine-sharing agreements that could be compromised if Washington’s domestic response falters. With the H5N1 avian influenza virus now circulating widely in American dairy cattle and sporadic human cases emerging, the political decisions made in Washington over the coming months could determine whether a localised animal outbreak becomes a global human crisis.

**Context**

The current alarm centres on the H5N1 clade 2.3.4.4b virus, which has been detected in more than 200 dairy herds across at least 14 US states since early 2024. While the virus has not yet acquired the ability to transmit efficiently between humans, each spillover event – such as the handful of mild human cases reported among farm workers – provides the virus with opportunities to adapt. The US Centers for Disease Control and Prevention (CDC) has maintained that the risk to the general public remains low, but critics argue that testing and surveillance efforts have been woefully inadequate. A recent analysis by the non-profit organisation Public Health Watch found that fewer than 100 people had been tested for H5N1 in the US during the first six months of the outbreak, a fraction of the number needed to detect silent chains of transmission.

Politically, the situation is complicated by the approaching US presidential election and the deep partisan divide over the role of federal health agencies. The administration of President Joe Biden has requested additional funding for pandemic preparedness, including a stockpile of H5N1-specific vaccines, but Congress has yet to approve the full amount. Meanwhile, former President Donald Trump, who is running for a second term, has signalled that he would dismantle key elements of the public health infrastructure built during the COVID-19 pandemic. His campaign has floated the idea of defunding the CDC’s outbreak response unit and reducing the authority of the National Institutes of Health. Such moves, if enacted, could severely hamper the US ability to contain a novel flu strain before it spreads beyond its borders.

For the UK, the stakes are particularly high. The British government’s pandemic preparedness strategy, updated in 2023, explicitly relies on international cooperation and early detection in countries where zoonotic diseases emerge. The UK Health Security Agency (UKHSA) maintains a close working relationship with the CDC and the World Health Organization (WHO), sharing genomic data and coordinating vaccine development. If the US were to experience a large-scale H5N1 outbreak that overwhelmed its public health system, the UK could face a double blow: a direct threat from the virus itself, and a collapse of the global surveillance network that provides the first line of defence.

**Analysis**

The political dimension of this potential pandemic cannot be overstated. Unlike the COVID-19 virus, which emerged from a wet market in China with no immediate political blame attached to Western governments, an H5N1 pandemic that originates in the United States would carry profound geopolitical consequences. The UK, as a close ally, would be forced to navigate a delicate diplomatic path: maintaining solidarity with Washington while potentially imposing travel restrictions or border controls that could strain the special relationship. Moreover, the UK’s own vaccine manufacturing capacity, centred on the Seqirus facility in Liverpool, is designed to produce pandemic influenza vaccines, but it relies on seed strains provided by the WHO and the CDC. Any delay in sharing those strains – whether due to political obstruction or simply overwhelmed laboratories – could leave the UK scrambling for doses.

There is also the question of public trust. The COVID-19 pandemic exposed deep fractures in how governments communicate risk and manage misinformation. In the US, the politicisation of mask mandates and vaccines has left a legacy of scepticism that could hinder a future flu response. If a new pandemic were to be perceived as a failure of the US political system rather than a natural event, it could fuel anti-American sentiment in Europe and beyond. The UK, which has its own history of vaccine hesitancy, would need to craft a messaging strategy that neither blames the US nor downplays the transatlantic origins of the threat.

**Sources**

This article draws on publicly available information from the US Centers for Disease Control and Prevention (CDC) regarding H5N1 surveillance and human cases; the World Health Organization (WHO) global influenza update reports; the UK Health Security Agency (UKHSA) pandemic preparedness framework; and statements from public health experts cited by outlets including the British Medical Journal and Reuters. No confidential or unpublished data has been used. All political positions referenced are based on official campaign platforms and public statements by candidates as reported by major news organisations.