Maeve Cullinan
Wed, November 4, 2026 at 10:00 PM PST
9 min read
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Is America on the brink of sparking a new flu pandemic?
America is closer than ever to harbouring the next flu pandemic, leading experts have warned.
H5N1, the avian flu that has decimated bird populations worldwide, is spreading through US cattle herds, raging on one of the country’s largest mink farms and, in the past few weeks, has infected three people in Washington state, one of whom has died.
The new cases bring the total number of people in the US infected with H5N1 since 2022 to 75. There have been three deaths.
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Scientists say deep cuts to the federal agencies responsible for protecting human and animal health under the Trump administration have allowed the virus to spread largely unchecked, sharply raising the risk of a human outbreak.
The more the virus circulates in animals, the more people are exposed to it, and the more chances it has to adapt to humans, experts say.
H5N1 has shown no sign so far of spreading between people, but if it did, it is feared the virus could trigger a global pandemic with a very high human cost.
The Telegraph spoke to leading virologists, many of whom argue that America is getting closer to becoming ground zero for the next flu pandemic.
It would not be the first time. The first case of H1N1, the “Spanish flu”, is thought to have emerged at an army base in Kansas in March 1918, and the pandemic went on to kill more than 50 million people.
“It does feel like a disaster waiting to happen,” said Prof Ed Hutchinson, a molecular and cellular virologist at the University of Glasgow.
“We keep having a series of near misses, and I wonder how long our luck is going to hold.”
A preventable outbreak
H5N1 reached the US in 2021, carried by wild birds that had migrated from Europe.
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For two years, it behaved much as it has elsewhere.
It infected farmed poultry, forcing mass culls at chicken and turkey farms, and occasionally jumped to mammals that had fed on infected carcasses, including seals, dolphins, bears, coyotes and foxes.
The same scenario has played out across the world, including in Britain, where more than three million farmed birds have been culled since 2020 in an attempt to stamp out the virus.
But in late 2023, there was a significant and unusual development in the US.
At a cattle farm in Texas, H5N1 infected a single dairy cow, most likely through contact with infected bird droppings in its feed. In most mammals, the virus quickly dies out, but this time it began spreading rapidly from cow to cow.
Within months, hundreds of herds across more than 12 states had been infected.
In the US, cows are often raised on farms in one state and then moved to large commercial milking centres in another, meaning that at any given time thousands of animals are being moved across the country.
Because cows infected with H5N1 do not always show obvious signs of illness, hundreds of thousands of sick cattle have been unwittingly moved across state lines, bringing the virus into new regions.
The practice has been heavily criticised for the biosecurity risk it carries.
“The cow infections have been totally preventable,” said Marc Johnson, a virologist at the University of Missouri.
“Cattle infection usually lasts a few weeks, and then they recover. If they just separated the infected herds or animals until it fizzled, then it would stop. But they keep moving cattle around and spreading it to new states.”
Surveillance efforts on cattle farms have also been significantly wound down under the Trump administration.
“There was a lot of openness and transparency at the end of the Biden administration, and they were really open about some of the challenges in getting farms to open up to testing,” Dr Devi Sridhar, a professor of global health at the University of Edinburgh, told The Telegraph.
“Then Trump came in, and everything went quiet. And I don’t think it went quiet because it went away. It went quiet because they just stopped tracking it.”
Of the 75 human cases in the US, at least 50 have been linked directly to cattle farming, meaning the outbreak in cows has become the main route by which the virus is reaching people.
Most human cases linked to cattle have been mild, and far less dangerous than historic cases linked to infections from wild or farmed birds. Of the roughly 1,000 human cases of H5N1 linked to birds since it first emerged in China in 1997, around half have died.
But on November 1, the first person to be infected with the cow variant of H5N1, known as genotype B.13, was confirmed to have died.
The individual, who worked on a farm in Washington where at least 40 herds have been infected with H5N1, had underlying health conditions, which may have exacerbated the disease, and died shortly after becoming sick – but the development is still of concern, say experts.
“This goes against the pattern of mild disease when infected from dairy cattle, versus severe disease when infected from birds, which is worrying given the circulation in cattle,” said Dr Sridhar.
Reassortment risks
One of the biggest fears among scientists is that bird flu could combine with ordinary seasonal influenza to create a new strain capable of spreading easily between people.
“This is a time of year when we can expect to see more circulation of [human] seasonal influenza,” said Dr Marion Koopmans, professor of public health virology at Erasmus MC Medical Centre in the Netherlands.
“A bad scenario would be that someone working with cattle brought the ‘regular’ human flu in, got [H5N1] on top of that, and that develops into a mix that can spread but to which people have less immunity.
“The chances of such an event are very low, but it is a concern shared among virologists.”
The process, known as reassortment, occurs when two flu viruses infect the same animal or person and exchange genetic material, potentially creating a new strain.
Scientists are particularly concerned as H5N1 spreads beyond cattle and into other mammals – chiefly mink.
For more than two months, an outbreak has raged on a Utah farm housing thousands of mink, according to an investigation by US news outlet ProPublica.
Mink farms have previously been described as potential pandemic “time bombs”, because their respiratory systems are similar to those of humans, meaning viruses spread easily between them and people.
Despite calls for the animals to be culled, Utah officials have so far refused to mandate action, ProPublica reported.
The investigation also suggested that state officials were prioritising the financial interests of the fur industry, which exports much of its produce to China and Russia, while federal authorities had failed to intervene.
H5N1 has previously spread through mink farms in Spain and Finland, but authorities in those countries took much tougher action.
“There was really vigorous state intervention and culling. In Finland, they used widespread culling and vaccination programmes,” said Prof Hutchinson.
“It doesn’t sound like there’s been a great deal of enthusiasm for intervention [in the US] on behalf of the authorities.
“So you have this ongoing situation where the virus is replicating on a mink farm, which would be an ideal situation for the virus to slowly adapt to something more suitable to humans.
“As we move into the flu season, more and more of the people are also likely to be carrying human influenza at the same time [as potentially being infected with H5N1].”
Prof Hutchinson also warned that the vulnerability of some farm workers could make the outbreak harder to monitor.
“In the US system, a lot of the people working in the farming sector are undocumented workers. They are less likely to be engaged with public health surveillance than some other groups for obvious reasons,” he said.
Reassortment has been the cause of several major flu pandemics.
In 2009, a new strain of H1N1, commonly known as swine flu, emerged in Mexico and spread around the world within months, ultimately causing an estimated 150,000 deaths.
The virus emerged after different strains of bird, pig and human influenza exchanged genetic material, creating a new strain to which much of the population had little existing immunity.
Several countries, including Britain, have stockpiled supplies of H5N1 vaccines designed for humans, in preparation for the possibility that the virus begins spreading between people.
The US holds a federal stockpile of five million doses of bird flu vaccine. The doses are grown and cultured inside chicken eggs, the traditional method of manufacturing seasonal flu jabs.
While effective, the process is relatively slow, and experts have warned that producing enough vaccines to meet demand in a pandemic could take months.
In May last year, US health secretary Robert F. Kennedy Jr., a vaccine sceptic, cancelled a $766 million contract with Moderna to develop an mRNA vaccine against H5N1 – a technology that could offer a much faster way of delivering vaccines than traditional egg-based production. He said the technology “poses more risks than benefits” for respiratory viruses – a view that experts said was baseless.
“This is how outbreaks happen,” Dr Krutika Kuppalli, associate professor in the Division of Infectious Diseases at the University of Texas Southwestern said.
“You have continued spread of the disease; you’re not controlling it, and it allows the virus to evolve. So at some point, we’ll potentially see more human cases.
“If we develop human-to-human spread, that could really set things off.”
The “blue tsunami” brought in by the US midterms could offer some hope, experts say.
Many hope that a new wave of Democrats in the House and Senate will put pressure on Trump to protect science funding and reinstate some of the people and departments fired in deep federal cuts to the US Centers for Disease Control and US Department of Agriculture last year.
“We’re hoping you’ll have more [strong] voices going into government, and more scientific transparency,” said Dr Sridhar.
