The 2025-2026 season was another severe one for children in the United States. More school-age children were hospitalized with flu than in any season since 2009. Fewer than half of children were vaccinated, despite the American Academy of Pediatrics (AAP) recommending the flu vaccine for every child 6 months and older.
The same questions come up every fall, most often from parents bringing a child in for a first flu shot: does it really work, will it actually protect my child, and isn’t this just the flu? For decades, research has shown that childhood flu vaccination saves lives. And a new 2026 research from Harvard Medical School confirms that: Pediatric flu vaccines significantly reduce the number of childhood cases of influenza.
The analysis drew on insurance claims for millions of children between the ages of 2 and 5, covering five ordinary flu seasons between 2016 and 2023. The two pandemic seasons were set aside, since school closures changed how flu spread and would have distorted any comparison.
Across those seasons, between nine and 14 out of every 100 vaccinated kids avoided a case of the flu they would have otherwise caught. At a national scale, the same effect translates to hundreds of thousands, possibly a million, childhood flu cases avoided in the United States each year.
What sets this study apart is not how large the effect is, but how well the researchers ruled out other explanations. Families who bring a child in for a vaccine also tend to have reliable well-child checkups, treat illnesses early, and keep a sick child home. Those habits alone would mean fewer flu diagnoses, vaccine or no vaccine.
So the researchers built in a check. If the vaccinated group had simply come from households like that, those children would have had fewer colds and fewer stomach viruses too. But rates of infections without an existing vaccine came out the same in both groups. Only flu was different, more clearly showing how much the vaccine helped prevent illness, even when controlling for other factors.
The flu shot prevents a measurable number of infections every season. And each infection it prevents is one that never travels home to a newborn sibling or a grandparent, or anyone who is at higher risk of illness.
In January 2026, federal health officials initially approved a revised childhood immunization schedule that moved influenza vaccination from a full recommendation for all children to what is called shared clinical decision-making, meaning a case-by-case conversation rather than a standing recommendation. That change was later challenged in court, so it is not currently in effect.
The American Academy of Pediatrics (AAP) continues to recommend flu vaccination every season for every child 6 months and older who has no medical reason to avoid it. Parents caught between conflicting messages this fall, including those weighing flu and COVID vaccines for children, can talk to their clinician rather than trying to understand the guidance alone.
A vaccinated child can still catch the flu, but vaccination can significantly reduce their severity of symptoms.
Flu viruses change from year to year, and in a season where the circulating strain drifts away from the version the vaccine was built to match, protection drops. This means that effectiveness estimates also move from season to season. And while some years the vaccine may offer weaker protection, it’s still worth having.
Parents thinking through vaccine safety for infants and first flu shots should think of the vaccine as a substantial, well-measured reduction in risk. The flu shot can’t fully prevent the disease, but it can significantly lower the odds that a child will get the flu–and the severe complications it can cause.
Need a pediatrician who will partner with you to protect your child through flu season? Schedule a visit with one of our clinicians.
References
1. American Academy of Pediatrics. (2026, August 10). AAP (influenza) flu prevention and treatment recommendations for 2026-27. HealthyChildren.org. https://www.healthychildren.org/English/news/Pages/aap-(influenza)-flu-prevention-recommendations-for-2026-27.aspx
2. American Academy of Pediatrics Committee on Infectious Diseases. (2026). Recommendations for prevention and control of influenza in children, 2026–2027: Policy statement. Pediatrics. https://doi.org/10.1542/peds.2026-078778
3. Leonard, J. S., Reinhart, K., Lu, P.-J., Santibanez, T. A., Srivastav, A., Hung, M.-C., Jain, A., Budd, A., Huang, S., Kniss, K., Price, A. M., Burns, E., Ellington, S., & Flannery, B. (2026). Influenza vaccine effectiveness against pediatric death in the United States: 2016–2025. Pediatrics, 158(2), e2026076453. https://pubmed.ncbi.nlm.nih.gov/42402353/
4. Lucaccioni, H., Marques, D. F. P., Kirsebom, F., Emborg, H.-D., Hamilton, M., Whitaker, H., Bolt Botnen, A., Bucholc, M., Pozo, F., Andrews, N., Trebbien, R., Rose, A. M. C., & Kissling, E. (2026). Influenza vaccine effectiveness from nine studies during drifted A(H3N2) subclade K predominance, Europe, September 2025 to January 2026. Eurosurveillance, 31(7), 2600109. https://doi.org/10.2807/1560-7917.ES.2026.31.7.2600109
5. Worsham, C. M., Bray, C. F., & Jena, A. B. (2026). Pediatric influenza vaccination efficacy. JAMA Pediatrics. https://doi.org/10.1001/jamapediatrics.2026.1546