And how Covid-19 played a key role.
Fall is in the air — and unfortunately, so is the flu. But this year’s vaccine isn’t exactly the same formula you’re used to, thanks to the coronavirus.
Researchers have discovered that the Covid-19 pandemic killed off a commonly circulating influenza strain known as Yamagata. That means people getting the flu shot will now be vaccinated against three strains instead of four, as has been the case for the last decade.
We took a closer look at this change and what else you should know about keeping your guard up this flu season.
What does this mean for the flu vaccine?
As of this fall, all flu shots are “trivalent,” meaning they protect against three different influenza viruses: an influenza A(H1N1) virus, an influenza A(H3N2) virus, and an influenza B/Victoria virus.
The strain notably missing from this vaccine concoction is Yamagata, which has been virtually rendered obsolete by the coronavirus. Scientists believe this was mainly due to mitigation efforts, such as masking and social distancing, at the height of the pandemic in 2020. (There was also already a fair amount of immunity to this particular strain, which has been in circulation since the 1990s. )
In response to these findings, officials decided to change the flu vaccine. In September, the World Health Organization said that “including the Yamagata-lineage antigens in influenza vaccines is no longer warranted,” and then a month later, the U.S. Food & Drug Administration decided that Yamagata strains should be dropped as quickly as possible.
“You don’t want to be vaccinating people for something they don’t need,” Dr. Paul Offit, a member of the FDA’s Vaccines and Biological Products Advisory Committee, told CNN.
How are health experts responding to this change?
Most health experts agree that dropping Yamagata from the vaccine formulation this was the right call. The general consensus is that including protection against the strain was unnecessary — and might even do more harm than good.
“Anytime these flu vaccines are being produced, they are — depending on which vaccines you are talking about — using live or attenuated virus, and you do have to grow it,” Dr. Jodie Guest told CNN, noting that this approach could run the risk of the strain getting out again.
Other researchers have also pointed out that dropping the Yamagata strain also frees up production to make more flu vaccines both in the U.S. and around the world.
What can we expect this flu season?
Just because there’s one less strain doesn’t necessarily mean that this flu season won’t be any less intense. The other B/Victoria and two influenza A strains are still circulating widely and making people sick.
With that in mind, the Centers for Disease Control and Prevention still recommends that everyone 6 months and older get the flu vaccine. This is especially important for people 65 years and up, who are prone to potentially life-threatening cases. Complications from the flu can lead to bacterial pneumonia and even worsen chronic conditions, such as congestive heart failure or diabetes.
And those complications might be more common thank you might think: The CDC estimates that between 12,000 and 51,000 people die every year from influenza, underscoring the importance of playing it safe and getting your dose of the vaccine.
