- New data shows that young children who get the flu vaccine every year can get broad protection.
- However, as children get older, the protection they get from vaccines against other strains of the flu is not uniform.
- Experts stress the importance of annual influenza vaccinations for children and adults.
For years, the percentage of Americans who get the annual flu shot has remained around 50%. While most people can get a flu shot — from the youngest to the oldest — new research suggests that kids may be especially helped.
A yearly flu shot can provide young children with antibodies that provide broad protection against the new strain of the virus — a benefit older children and adults don’t get, according to a new study.
The study was published in the journal Cell Report Medicineanalyzed immune response data in children aged 3 to 15 years.
The researchers found that children were more likely to develop broadly protective antibodies against the flu at a young age.
As they grow, the antibodies they develop from catching the flu or getting a viral vaccine are still effective against the flu, just less widely.
The researchers also compared the antibody responses of the flu vaccine to the nasal spray vaccine and found that both were equally effective at producing protective antibodies.
How the flu shot works and why it sometimes doesn’t
How the flu vaccine works
The flu shot makes your body develop antibodies against certain strains of the flu virus. It takes about two weeks after vaccination for protection to take effect.
These antibodies help protect you against infection or serious illness from flu strains that are circulating in certain seasons.
Each year, researchers analyze data from around the world to try to figure out which flu strains are most common during the upcoming flu season. Then, they try to adjust the vaccine to match.
All flu vaccines in the U.S. protect against three (trivalent) or four (tetravalent) strains of influenza virus: influenza A (H1N1) virus, influenza A (H3N2) virus, and one or two influenza B viruses . (Only the quadrivalent vaccine is available for the 2021-2022 flu season.)
2021-2022 Influenza Vaccines
According to the U.S. Food and Drug Administration (FDA), the 2021-2022 flu vaccine is designed to protect against the following flu strains:
- A/Victoria/2570/2019 (H1N1) pdm09-like virus
- A/Cambodia/e0826360/2020 (H3N2)-like virus
- AB/Washington/02/2019-like virus (B/Victoria lineage)
- AB/Phuket/3073/2013-like virus (B/Yamagata lineage)
Universal flu shot could replace your annual shot
How well does the flu vaccine work?
The flu vaccine is different from year to year, which means its effectiveness may vary depending on the flu season.
According to the US Centers for Disease Control and Prevention (CDC), the effectiveness of vaccines in preventing influenza infection ranged from as low as 10% during the 2004-2005 flu season to as high as 60% during the 2010-2011 flu season.
Efficacy in the 2019-2020 season (the latest season for which data are available) showed that the vaccine was 39% effective in preventing influenza in those who received it.
Why are some flu seasons worse than others?
The importance of the flu vaccine
While the flu vaccine “is not perfect, it does help protect people from hospitalization,” Thomas Russo, MD, professor and chief of the Division of Infectious Diseases at the University at Buffalo, told VigorTip Health.
According to Russo, the latest research shows that your response to the flu vaccine “depends in part on your previous exposure to live influenza strains, your previous vaccinations, and when you were vaccinated.”
Children may develop broader antibody responses to the flu vaccine simply because they are not regularly exposed to the flu, if at all, Russo added.
Thomas Russo, MD
Every able-bodied person should get the annual flu shot.
—Thomas Russo, MD
Adults are a bit different because they “have more pre-existing antibodies that can dampen vaccine responses,” Richard Watkins, MD, an infectious disease physician and professor of internal medicine at Northeastern Ohio Medical University, told VigorTip. .”
Given the differences in immune responses, Watkins said, “it may be easier to develop a universal flu vaccine for children than for adults.”
Infectious disease expert Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, told VigorTip, “The point is that the annual flu vaccine produces broadly neutralizing antibodies.”
Adalja stressed that adults can still get the benefits and antibodies from the vaccine, and “probably because children’s immune systems are not ready” to respond to the virus the same way adults do with continued exposure to the virus through vaccination and infection.
The study demonstrates the importance of annual flu vaccinations for adults and children, Russo said. ”
We don’t want to take home the message that it’s futile for adults to get a flu shot — that’s not true,” Russo said. “Everyone who can afford it should get a flu shot every year. ”
what does this mean to you
Children of all ages may still benefit from getting a flu shot every year for broader protection than adults.
Cell-based flu vaccine shows promise in kids