Why this year's flu shot targets three strains instead of four: HealthLink

SEATTLE — There's something different about this year's flu vaccine, and we're thankful for the pandemic.

For the first time in more than a decade, the vaccine will target three strains of influenza instead of four. Doctors told KING 5 that's actually a good thing.

It wasn't that long ago that people were collectively asked to wear masks and stay indoors to quell the coronavirus. As it turns out, these precautions ruined something else along the way.

“Yamagata stocks were already on the decline, but this was the nail in the coffin,” said Dr. Matt Gentry, Rite Aid's Washington-based pharmacist.

He's referring to strains of influenza that have disappeared in recent years.

The U.S. Food and Drug Administration announced in March that the influenza vaccine for the 2024-2025 season will be: trivalentIt covers three types of influenza instead of the traditional four.

“I thought you know this year's flu vaccine is different, but not many people know why,” Gentry said.

Gentry said the change is exciting.

“The important question is, why are there only three stocks this year?” Gentry added.

Years of coronavirus disease (COVID-19) precautions during the pandemic have helped prevent the spread of coronaviruses and a specific influenza strain known as Influenza B/Yamagata. Influenza B/Yamagata happened to be already on the decline at that time and had not been detected since March 2020. .

“We have eliminated the influenza strains that are circulating around the world,” Gentry said.

The Centers for Disease Control and Prevention and the World Health Organization have announced that the Yamagata strain does not exist and will not be included in this season's flu vaccines.

Since the 2012-2013 season, the available influenza vaccination is quadrivalent, which targets four strains: two influenza “A” strains and two influenza “B” strains.

According to the CDC, the influenza vaccine for the 2024-2025 season currently targets only two Victoria strain “A” strains and one “B” strain. The aforementioned B/Yamagata stock will be omitted.

I talked to KING5 Dr. Helen ChuFor further insight, please see Professor of Infectious Diseases in the Division of Allergy and Infectious Diseases at the University of California School of Medicine.

“Influenza B is a virus that can only be transmitted from person to person, and it doesn't involve pigs or birds, so what happened was that humans couldn't transmit it to each other, so it was completely eliminated,” Chu said. he said. .

“I think what this report is telling us is that we can definitely stop the transmission of the virus by measures like wearing masks and staying home when we're sick. That level of control. “Whether we want to take these measures on a regular basis is probably something to be debated. But certainly in a pandemic, if we take these steps, we can stop the transmission of other viruses.” he said.

While the changes to this year's flu shot may seem small to the general public, Gentry said it's a huge success.

“All the pain we went through had meaning. It mattered,” Gentry said.

CDC cannot definitively say that the B/Yamagata influenza strain is permanently extinct. Other types of influenza B disappeared for a time, then reappeared. Therefore, the CDC and WHO will continue to monitor this.

But what about a cold? Respiratory infections plague countless people not only throughout the year, but also during peak seasons.

Researchers are better understanding why we keep catching new colds, even though we only get the flu and the coronavirus once per season.

University of Wisconsin Medical researchers have found that different rhinovirus variants circulating at once may cause people to catch colds more than once, according to a study by Stephanie Goya, Ph.D., a postdoctoral fellow in the Department of Medicine and Pathology at the University of Wisconsin. discovered that this is the reason. medicine.

Mr. Goya the study Published in the Infectious Disease Journal.

Rhinovirus is the most common virus that causes the common cold.

“Each of these versions doesn't mutate and doesn't change very much. So if we have a chance to know everything, this is very promising for us to consider as a potential vaccine,” Goya said.

For more information about where you can get a coronavirus or flu vaccine, visit: here.