Flu Virus With Pandemic 'Hallmarks' Emerges in China: Should We Be Worried?

Scientists have found a virus in pigs they say has the "hallmarks" of a bug which could cause a pandemic in humans. However, experts told Newsweek that while the news is concerning, the general public shouldn't be alarmed.

The virus, called G4 EA H1N1, has become "predominant" in pig populations in China since 2016, according to the authors of the study in the journal PNAS. Antibody tests also suggest it has infected some humans.

The germ has similarities to the virus that caused the 2009 H1N1 flu outbreak, including its ability to bind to a receptor to invade pig cells which is similar to that in humans. It was also found to replicate in human airway cells in a lab, and infect and spread between ferrets, which are often used as a model of disease in humans. In addition, it is unlikely that any immunity people have against other types of flu from vaccines would be protective, the team said.

Similarly to the H1N1 virus, the bug had "all the essential hallmarks of a candidate pandemic virus" and posed a "serious threat to human health."

The scientists found the bug after collecting 179 viruses from pigs in 10 Chinese provinces with high-density swine populations between 2011 and 2018.

They also studied over 338 blood samples from swine production workers between 2016 and 2018 from 15 pig farms, and 230 from members of ordinary households. They found 10.4 percent of the workers and 4.4 percent of the general population had antibodies for the virus, suggesting they had been infected by it.

The team said it was "of concern" that antibody tests on swine workers appeared to show they had the virus.

In light of the findings, measures to control the virus in pigs and closely monitor human populations, particularly those in the swine industry, "should be urgently implemented," the authors wrote.

Co-author Kin-Chow Chang, professor of Veterinary Molecular Medicine at the U.K.'s Nottingham University in the U.K., told BBC News: "Right now we are distracted with coronavirus and rightly so. But we must not lose sight of potentially dangerous new viruses."

He told the outlet the virus isn't an immediate problem, but "we should not ignore it."

Experts who did not work on the study said the findings were worrying but didn't signal an immediate threat.

Professor James Wood, head of the Department of Veterinary Medicine at the U.K.'s University of Cambridge, said in a statement the team's investigation was "thorough."

Wood said pig farming is a massive industry in China and these animals can be important hosts from which new flu viruses emerge.

"The work comes as a salutary reminder that we are constantly at risk [of new pathogens which can jump from humans to animals] and that farmed animals, with which humans have greater contact than with wildlife, may act as the source for important pandemic viruses," he said.

Asked by Newsweek if the general public, politicians and policymakers should be worried about this virus, he said: "I do not believe that this is something for the public to be worried about but I do think that this is something that is important for policy makers and contingency planners. There is of course a world of difference between the two!"

Dr. Yohei Yamauchi, who studies the cell biology of viruses at the University Bristol, U.K., told Newsweek it was "remarkable" that members of the general population had antibodies for G4 EA H1N1, "though at low percentages."

He said: "This indicates that G4 [EA H1N1] can infect and spread in humans."

However, even if the virus were to cause a pandemic, that doesn't necessarily mean it would kill a lot of people, he said, pointing to the 2009 H1N1 swine flu outbreak.

"However, an influenza epidemic/pandemic on top of COVID-19 will increase the strain on the economy and health services and possibly put more lives at risk," he said. The possibility of people being infected with both G4 EA H1N1 and the coronavirus that causes COVID-19 "cannot be ruled out, and this would mean an uncharted territory for clinicians and researchers," he said.

The study is important as it may help researchers and institutions like the U.S. Centers for Disease Control and Prevention and the World Health Organization to prepare by designing vaccines, said Yamauchi.

Dr. Silviu Petrovan, a veterinarian and wildlife researcher at the University of Cambridge, told Newsweek adequate biosecurity and surveillance mechanisms need to be put in place to prevent such pathogens from causing another pandemic.

He said he wouldn't want to speculate on whether the public should be worried, "other than to say that it seems clear that if we want to reduce the chances of another pandemic then 'business as usual' is probably not a good way forward in relation to how we interact with animals, including livestock."

Petrovan went on: "The global incidence of emerging infectious disease from animals appears to be increasing in recent decades and combined with the extraordinary levels of global human mobility, this creates opportunities for such incidents, although still relatively rare, to have the kind of catastrophic consequences as we are seeing currently with COVID-19.

"Collectively, we can and should do better."

Holly Shelton, head of the Influenza Viruses Group at The Pirbright Institute, U.K., told Newsweek: "Discovering that a virus that is widespread in the pig population of China has the ability to attach and replicate in human model systems inside the laboratory really emphasizes the need to maintain surveillance, control influenza viruses in farmed animal populations and the critical importance of maintaining good bio-security in these settings."

This article has been updated with comment from Holly Shelton.