He warned: “A new year might mean new viral threats.”
An infectious diseases expert warned of three viruses that could pose a threat this year(Image: Getty)
An expert has named three viruses that could pose a serious threat to humans in 2026. These bugs could be “poised” to cause infections in “unexpected places or in unexpected numbers”.
Writing for The Conversation, Patrick Jackson – the assistant professor of infectious diseases at the University of Virginia, warned that the threat of widespread illnesses is constantly looming. He explained: “A new year might mean new viral threats. Old viruses are constantly evolving.
“A warming and increasingly populated planet puts humans in contact with more and different viruses. And increased mobility means that viruses can rapidly travel across the globe along with their human hosts.
As an infectious diseases physician and researcher, I’ll be keeping an eye on a few viruses in 2026 that could be poised to cause infections in unexpected places or in unexpected numbers.”
Influenza A
Influenza A is one of four known types of influenza, or flu. Viruses from influenza A are the only kind of influenza known to lead to pandemics.
Prof Jackson warned that we are “on the cusp of a pandemic” caused by influenza A. “Influenza A is a perennial threat,” he said. “The virus infects a wide range of animals and has the ability to mutate rapidly.”
In 2009, an influenza pandemic, caused by the H1N1 subtype – also known as swine flu, killed more than 280,000 people worldwide in its first year. This is still circulating today.
The expert also highlighted concerns around the highly-pathogenic avian influenza H5N1 subtype, or bird flu, which comes from influenza A. He said: “This virus was first found in humans in southern China in 1997; wild birds helped spread the virus around the world. In 2024, the virus was found for the first time in dairy cattle in the U.S. and subsequently became established in herds in several states.
“The crossover of the virus from birds to mammals created major concern that it could become adapted to humans. Studies suggest there have already been many cow-to-human transmissions.
“In 2026, scientists will continue to look for any evidence that H5N1 has changed enough to be transmitted from human to human – a necessary step for the start of a new influenza pandemic. The influenza vaccines currently on the market probably don’t offer protection from H5N1, but scientists are working to create vaccines that would be effective against the virus.”
Mpox
Prof Jackson said mpox is “worldwide and liable to worsen”. Formerly known as monkeypox, the virus actually mostly infects rodents and occasionally crosses over into humans.
“Mpox is closely related to smallpox, and infection results in a fever and painful rash that can last for weeks,” he said. “There are several varieties of mpox, including a generally more severe clade I and a milder clade II.”
A vaccine for mpox is available, but there are currently no effective treatments. In 2022, a global outbreak of clade II mpox spread to more than 100 countries that had never seen the virus before.
This outbreak was driven by human-to-human transmission of the virus through close contact, often through sex. He added: “While the number of mpox cases has significantly declined since the 2022 outbreak, clade II mpox has become established around the world.
“Several countries in central Africa have also reported an increase in clade I mpox cases since 2024. Since August 2025, four clade I mpox cases have occurred in the US, including in people who did not travel to Africa.” According to the UK Health Security Agency (UKHSA), clade I mpox cases have also been detected in the UK.
Oropouche virus
This is an insect-borne virus and, according to Prof Jackson, is “poised to spread”.It is carried by mosquitoes and small biting midges. Prof Jackson said: “Most people with the virus experience fever, headache and muscle aches. The illness usually lasts just a few days, but some patients have weakness that can persist for weeks. The illness can also recur after someone has initially recovered.”
It was originally found in Trinidad and Tobago but has since spread to wider parts of South America, Central America, and the Caribbean. He said: “Cases in the United States are usually among travellers returning from abroad. In 2026, Oropouche outbreaks will likely continue to affect travellers in the Americas.
“The biting midge that carries Oropouche virus is found throughout North and South America, including the southeastern United States. The range of the virus could continue to expand.”
The UKHSA warned that a “small number” of travel-associated cases of Oropouche have been reported in the USA and Europe, including the UK.
