New Study Suggests Flu Vaccine May Not Protect Against This Year’s Main Flu Strain
New research suggests the current flu vaccine may not protect against the most common strain of influenza.
Scientists are concerned about a heightened flu season due to last year’s very low cases amid the COVID-19 pandemic (Here's more about when flu season starts).
Experts still recommend getting your flu vaccine, as research suggests this will protect against the severity of the virus.
The main influenza virus circulating may not match that of current flu vaccines, according to a new report (Please note: The study has been posted on a preprint server online and has not been published in a peer-reviewed journal at this time.) Health professionals still say the flu shot is still an important part of prevention and may help avoid serious illness or health complications.
According to the study, the flu virus was at a low circulation during the COVID-19 pandemic due to social distancing, mask-wearing, and a decrease in travel, and researchers have had concern over the average person’s ability to fight off the flu virus as COVID-19 restrictions continue to lift. The study found that the flu virus is spreading during the 2021 to 2022 season, and the current flu vaccine may not effectively protect people against this year’s particular strain.
“From our lab-based studies it looks like a major mismatch,” Scott Hensley, Ph.D., a professor of microbiology at the University of Pennsylvania who led the study, told CNN.
Hensley explained that the influenza vaccine is designed to protect against four specific strains of the flu: H3N2, H1N1, and two strains of the influenza B. This particular study covers the H3N2 strain, which is the most common type of flu seen this season. It appears that this version of H3N2 has mutated to avoid the antibodies the vaccine helps our bodies make, he told CNN.
Between a recent flu outbreak at the University of Michigan and reports from October 2021 that flu cases were up 23% from 2020, this shouldn’t come as a shock. But that doesn’t mean you should skip your flu vaccine this year if you haven’t gotten it yet. In fact, a flu vaccine is an important part of protecting yourself and your loved ones from serious illness from the flu.
“Studies have clearly shown that seasonal influenza vaccines consistently prevent hospitalizations and deaths even in years where there are large antigenic mismatches,” the researchers wrote in the study. “Influenza vaccinations will be crucial for reducing hospitalizations as SARS-CoV-2 and 2a2 H3N2 viruses co-circulate in the coming months.”
How is the flu vaccine developed?
Flu vaccines are created based on a prediction scientists make every season on what will be the dominant flu strain. The World Health Organization works in 148 labs in 120 countries to collect specimens from people with flu-like symptoms over the course of their typical flu season, Richard Webby, Ph.D., an influenza expert in the Infectious Diseases department at St. Jude Children's Research Hospital previously told Prevention.
“This group meets a couple of times of the year and asks a pretty simple question: Looking at the vaccine strains that we have now, how closely do those match the strains that we think are going to predominate in six months’ time?” he explained.
Then, each country will use the vaccine they think will be best for their population. And every year there’s a question of how effective the flu vaccine will be, and there’s always a chance it will not match the exact strain that becomes the most popular. For example, in the 2010-11 flu season, 60% fewer healthy adults who were vaccinated got the flu compared to those who were unvaccinated. In comparison, only 19% fewer healthy adults who were vaccinated got the flu in the 2014-15 flu season, according to the CDC.
This year, the Food and Drug Administration has released nine different “lots” of the flu vaccine, and though they have a lot in common, each flu shot vaccine has its own slightly different ingredients.
Flu symptoms
Similar to a cold, the flu will leave you with a sore throat, swollen glands, runny or stuffy nose, a cough, weakness or fatigue, and likely some sneezing. What differentiates the flu from a cold is the presence of headaches, muscle or body aches, a fever, and chills.
And even though it’s important to differentiate between cold vs. flu symptoms, it’s even more important to simply stay home if you’re feeling ill to avoid spreading the flu, or anything else, to other people. After all, the flu is most contagious one to four days after you start feeling sick, but the length of how long the flu is contagious can vary.
How to prevent the flu
The best thing you can do to prevent the flu, even with this new research, is to get your flu shot. Doctors agree it is still an important step to protecting yourself and your loved ones against the influenza virus.
“As we have seen with the COVID vaccine, even if the flu shot doesn’t keep you from getting infected, it certainly decreases your risk of getting severely sick,” Webby previously told Prevention.
Additionally, the CDC suggests staying away from others who are sick, covering your coughs and sneezes, washing your hands often, and practicing social distancing when necessary.
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