A new strain of flu has been identified by scientists in China which has the potential to become a pandemic, they say.
The virus, called G4 EA H1N1, is carried by pigs but can infect humans, scientists said in a new research paper.
And as it’s a new strain, humans are likely to have little or no immunity – meaning the virus needs close monitoring.
One of the authors of the study into the new virus said “we should not ignore” the findings.
Prof Kin-Chow Chang, of Nottingham University in the UK, told the BBC: “Right now we are distracted with coronavirus and rightly so. But we must not lose sight of potentially dangerous new viruses.”
The paper said: “G4 viruses [which this virus is one of] have all the essential hallmarks of a candidate pandemic virus. Of concern is that swine workers show elevated seroprevalence for G4 virus.”
Scientists and public health experts are always on the lookout for new kinds of flu.
A leaked Government document from last year shows that officials saw pandemic influenza as one of the two most significant threats to national security.
The last time a new strain of influenza became pandemic was swine flu, in 2009.
The outbreak ended up being less serious than feared, as people across the world appeared to have built up a degree of immunity from previous flu outbreaks.
Despite this, as many as 575,000 people died in the first year of the swine flu outbreak, according to the US Centre for Disease Control.
The new virus is reportedly similar to swine flu, but with some important differences, according to scientists.
Writing in the journal Proceedings of the National Academy of Sciences, the researchers said that the new strain, called G4 EA H1N1, hasn’t yet had a big impact.
There is evidence that workers in local abattoirs and people in other jobs that have contact with pigs have contracted the virus, they added.
Flu vaccines currently in use do not protect against the new strain, but could possibly be adapted, they said.
The scientists recommended that measures to control the virus and closely measure local populations should be brought in swiftly.