A masked worker checks the pigs in a hog pen in southwest China in February 2020. Photo: Feature China/Barcroft Media via Getty Images
A flu virus found in pigs in China has pandemic potential and should be "urgently" monitored, researchers warn in a study in the peer-reviewed journal PNAS this week.
Threat alert: While it has not been transmitted from human to human, the virus is raising concern because it is a genetic mix of strains that have devastated humans before and there are indications it has "acquired increased human infectivity," the researchers say.
Driving the news: NIAID director Anthony Fauci told a Senate hearing on Tuesday there was no immediate threat but they are keeping an eye on it.
Details: The flu's genetics include characteristics from the 2009 and 1918 flu pandemics. "They’re seeing the virus in swine, in pigs now, that have characteristics of the 2009 H1N1, of the original 1918, which many of our flu viruses have remnants ... as well as segments from other hosts, like swine,” Fauci said.
- The researchers' other concern is that 10% of 338 people who worked with swine tested from 2016 to 2018 were found to be positive for the virus, G4 EA H1N1 (although most had not reported being ill).
- They also note two cases, reported in 2016 and 2019, of swine influenza virus in a 46-year-old and a 9-year-old caused by G4-like EA H1N1 virus. Both had neighbors who reared pigs, suggesting the virus "could transmit from swine to humans, and lead to severe infection and even death."
- "Thus, it is necessary to strengthen the surveillance effort of G4 EA viruses among swine and human populations," the study states.
Background: The research team identified the virus as becoming predominant in swine populations since 2016. They had been collecting and evaluating 30,000 nasal samples from pigs from 2011 to 2018.
What they're saying: "We've always had potential pandemic flu viruses that we worry about ... they just don't have a media moment like pandemic viruses are having right now," Amesh Adalja, senior scholar at Johns Hopkins Center for Health Security, tells Axios.
- "This is one of the flu viruses we'll have to keep track of, and watch, and understand what its potential might be for causing human infections, just like we do for H5N1 and H7N9, which are the other two potential pandemic flu viruses that we've also been tracking," Adalja says.
What's next: If the virus does start human-to-human infection and moves toward an epidemic or pandemic, scientists will likely work on developing a targeted flu vaccine similar to 2009, but this does re-emphasize the need for a universal flu vaccine, says Adalja.