COVID Pandemic May Have Driven a Flu Strain Into Extinction

MONDAY, Oct. 25, 2021 (HealthDay News) -- It's well-known that COVID-19 pandemic restrictions beauteous overmuch quashed the 2020-2021 flu season, with influenza cases falling to never-before-seen lows successful the United States.

So small flu circulated, successful fact, that immoderate scientists present fishy that 1 of the large strains of influenza mightiness person gone extinct, for deficiency of humans to infect.

Influenza B/Yamagata is 1 of 4 strains regularly included successful yearly flu shots, but successful the midst of COVID lockdowns that strain appears to person fallen wholly disconnected the radar, an Australian probe squad precocious reported successful the diary Nature Reviews.

No B/Yamagata strains person been isolated oregon genetically sequenced successful flu lawsuit tracking since March 2020, erstwhile COVID lockdowns fundamentally ended the 2019-2020 flu season, the researchers said.

Only 31 suspected B/Yamagata cases person been reported to nationalist wellness officials from the astir caller flu season, but determination was nary palmy isolation oregon sequencing of the microorganism to find that B/Yamagata was genuinely to blame.

B/Yamagata has ever tended to beryllium little infectious than the different large flu strains, researchers noted. That strain besides doesn't germinate arsenic energetically arsenic the others; vaccine manufacturers haven't had to update the B/Yamagata constituent of the yearly flu changeable since 2015.

Those factors, "combined with suppressive conditions of the COVID-19 pandemic, whitethorn person facilitated beardown suppression of planetary B/Yamagata circulation and the imaginable extinction of this lineage," the researchers concluded successful their report. Marios Koutsakos, a postdoctoral probe chap astatine the University of Melbourne, led the study.

If an full strain of influenza has so gone extinct, that would unfastened up caller possibilities for tackling the yearly flu going forward, American infectious illness experts said.

But they archetypal caution that it'll instrumentality longer than 1 flu play to find whether B/Yamagata has bitten the dust.

"I'd beryllium a small leery of calling it a done deal, due to the fact that flu's a fickle small beast," said Richard Kennedy, a apical vaccine researcher with the Mayo Clinic successful Rochester, Minn.

Continued

He noted that B/Yamagata tends to surge successful definite years and past virtually vanish successful others.

"Just the grounds we haven't seen it for a while, I don't deliberation that by itself is simply a convincing argument," Kennedy said. "Data suggesting that since we haven't seen a azygous lawsuit since March 2020, that's good, but I'd similar to spot a longer play wherever we don't spot immoderate of it, due to the fact that it's hidden from america before, these lineages."

Now, COVID restrictions person relaxed and kids are backmost successful school, raising concerns among nationalist wellness officials that this flu play could beryllium a pugnacious one. B/Yamagata could resurface, helium said.

"These viruses are precise bully astatine making up for mislaid clip and mislaid region successful this race," Kennedy said. "We mightiness get ahead, but if we don't continue, we can't get a grip connected it."

If B/Yamagata is genuinely gone for good, that means we could juggle the strains included successful the yearly flu vaccine to get much bang for our buck, said Dr. William Schaffner, aesculapian manager of the Bethesda, Md.-based National Foundation for Infectious Diseases.

The operation of the existent flu vaccine includes 4 strains: influenza A/H3N2 (Hong Kong), influenza A/H1N1 (Swine), influenza B/Victoria, and influenza B/Yamagata. The influenza A strains thin to beryllium much infectious and the root of deadly epidemics, portion influenza B percolates much dilatory among school-age children and teens.

Each twelvemonth U.S. scientists play a guessing crippled to find which familial mentation of each of the 4 strains is apt to beryllium the astir infectious, Kennedy said. When they conjecture right, the flu vaccine provides amended protection.

Replacing the B/Yamagata portion of the vaccine with different strain that's much infectious and unsafe could amended the shot's effectiveness, Schaffner said.

"Could you treble up connected the adjacent astir terrible strain, H3N2? Could you get 2 H3N2s successful there?" Schaffner said.

Kennedy agreed. "Being capable to prime different strain that's not B, that's an A strain, would astir apt assistance with that guessing game," helium said.

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On the different hand, the vaccine could beryllium chopped backmost to conscionable 3 strains, which would marque the changeable cheaper and easier to manufacture, Kennedy said.

"You're capable to manufacture much doses oregon possibly driblet the outgo a small bit. That makes the vaccine much accessible for everyone," helium said.

If radical get the flu changeable this twelvemonth and instrumentality to COVID protections similar masking and societal distancing, there's a accidental that B/Yamagata mightiness beryllium gone for good, Kennedy and Schaffner agreed.

"We did larn from the past play that if you were profound successful your disguise wearing and societal distancing, staying home, closing schools, limiting travel, you could truly profoundly abort the yearly influenza outbreak," Schaffner said. "Some of that I deliberation volition travel back, and I deliberation we'll spot much of that successful accepted nationalist wellness recommendations."

As flu enters communities, determination volition beryllium reminders for folks who are much apt to get much terrible illness to enactment connected masks again, helium said.

"We cognize they're nary longer dorky. They're not conscionable utilized successful Japan," Schaffner said. "We cognize however to usage them, truthful get your masks out."

More information

The U.S. Centers for Disease Control and Prevention has more astir the yearly flu shot.

SOURCES: Richard Kennedy, PhD, professor, medicine, Mayo Clinic, Rochester, Minn.; William Schaffner, MD, aesculapian director, National Foundation for Infectious Diseases, Bethesda, Md.; Nature Reviews, Sept. 28, 2021