A: NOT SO FAST….. despite the clickbait headlines, this particular scientific study only points to a virus that we need to keep a careful eye on, NOT an immediate public health threat.
For the quick take on this story, we turn to University of Washington biologist (and amazing COVID-19 twitter source) Dr. Carl Bergstrom.
Carl writes in his Twitter thread: “The paper reports on a surveillance project looking at flu strains in pigs in China from 2011-2018. Pigs are an important reservoir for influenza, which can jump from this species to humans wholesale or by genomic recombination with a human strain.”
The main finding is that a new genotype of H1N1 flu, known as G4, emerged and by 2016 became the dominant strain in pigs. So that’s the first thing to notice. This is not a *new* new virus; it’s been very common in pigs since 2016.
The study also finds that the virus is different enough from previous H1N1 strains that human populations would not currently be immune, should it start to spread. Moreover it has a number of characteristics that *could* make it well suited to spreading in humans.
It was formed by recombination between a previous dominant strain in swine, and the human 2009 H1N1 virus, and other sources.
The virus is capable of infecting humans, with two zoonotic cases briefly mentioned in the paper. Neither resulted in human-to-human transmission.
Swine-to-human transmission is probably far more common, however. About 10% of those working with pigs have antibodies to G4, whereas antibodies are rare in humans elsewhere.
So are we facing the start of a double pandemic, COVID + influenza? Not imminently. There’s no evidence that G4 is circulating in humans, despite five years of extensive exposure. That’s the key context to keep in mind.
The paper is not describing an immediate threat to the general public, despite news outlets running headlines that suggest otherwise. The problem with the click-based advertising model is that there are strong incentives to get you to click.
What the paper does do is something important for the epidemiological community: it points to a virus that we need to be keeping a careful eye on. That’s something we can do. Screening will be important, particularly if clusters of illness emerge in swine workers.
But every indication is that the G4 virus would have to undergo some evolutionary change to spread readily in people, and it may never do that. If it does? We know how to make vaccines for influenza viruses. It could be included in the seasonal vaccine; the only issue is timing.
So that’s the G4/H1N1 story. Worth watching for people in the field. No immediate threat to public health.”
For all of you EXTRA nerdy nerds out there, Dr. Angela Rasmussen, Columbia University, has a great thread on the same study with loads of interesting virology details. Her bottom line is similar:
“We need to keep an eye on it but we should not focus on any one virus exclusively. We should prepare for ANY kind of emerging influenza pandemic. Ex: we know how to make effective flu vaccines…we could do some basic experiments to see how well a vaccine for this virus works.”
“What we should NOT do is freak out and expect that another flu pandemic is imminent. We should prepare for the flu pandemic that will come: maybe this fall, maybe not for another few years, but is inevitable.”
The Nerdy Girls could not have said it better ourselves, thanks Carl and Angela!
Remember Lindsey’s Laws: Exceptional claims require exceptional evidence.
Stay safe AND sane everyone!
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Helpful summary of the above points
