UW Medicine director: Flu strain ‘could be going extinct’ thanks to pandemic precautions

For the past year-and-a-half, people around the world have put on masks, stayed home, and diligently washed their hands to protect against COVID-19, but it appears that these precautions have also caused some major changes for another serious virus — the flu.

While flu in general has been far less prominent around the world in the past year, one particular strain has especially been missing in action.

The two types of flu that get people sick every fall and winter are influenza A and influenza B. In a recent study published in Nature Reviews Microbiology, scientists noted that one of the two main strains of influenza B has all but disappeared around the world in recent months.

A ‘dramatic drop’ in flu cases is silver lining of COVID pandemic

“What’s been really interesting, and what this study is looking at, is that we’ve only had a few reports of a very specific subtype of influenza B since 2021, and that really raises the question about whether this type of influenza could be extinct or could be going extinct,” explained Dr. Seth Cohen, medical director of Infection Prevention at UW Medical Center.

Cohen said that if that strain is gone, it would bode well for future flu vaccines. Only four strains are currently used in the annual vaccine — two influenza A strains and two influenza B strains, chosen based on scientists’ best guesses of which strains will be dominant that year. Having one fewer strain to worry about would free up space for others.

“If we had more room … if you take away one of those influenza B strains, we could put in something else, like another influenza A strain, to help prevent other types of flu that could cause severe infection,” Cohen said.

Eventually, researchers hope to have one mRNA “super vaccine” that would protect against every single flu strain.

“The holy grail of flu vaccines would be to develop a universal flu vaccine that would be a single dose that protects against all known strains of influenza … and might even be longer lasting, so people wouldn’t have to get their seasonal flu shot,” Cohen said.

Whether or not the “missing” strain of influenza B is gone for good, the decrease in cases is strong evidence for the benefits of wearing masks, staying socially distant, and taking other similar precautions worldwide.

“It really goes to show how powerful a lot of these public health interventions are that we have not done previously on a large scale,” Cohen said. “One of the few silver linings to come out of COVID is we’ve seen a decrease in a number of respiratory viruses, including influenza.”

Cohen expects that even after the coronavirus pandemic is behind us, some people will continue to wear masks in the fall and winter.

“Certainly in hospitals, it’s really changed the way we think about respiratory viral season,” Cohen said. “For us in health care, it’s hard to imagine going back to a respiratory viral season where people are not masked.”

He encourages people to keep up with the masking in a future non-COVID era, noting that there are no downsides to protecting oneself against the seasonal bugs. As long as you get your annual flu shot, he said, your immune system will still build up a strong response without having to go through the annoyance and risk of getting sick.

And this year especially, as hospitals remain near full capacity and short on staff — and as health officials nervously eye the plateau in COVID cases, worried we could see another surge — Cohen said it is vital for people to get their flu shot to help keep as many people out of hospitals as possible.

“The vaccines are terrific at preventing infection, but what they’re really designed to do is keep people out of the hospital and keep people from dying. And so for health care workers, we directly see the impacts of these vaccines in our communities,” he said. “If people can get vaccinated for COVID and for influenza, to us that means we’re keeping people out of the hospital and making sure we have beds available to care for people who really need to be hospitalized.”

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