A new study from the CDC found that annual flu vaccination reduces the risk of flu-related hospitalizations and medical visits in children by as much as 60%, yet fewer than half of children received the vaccine between 2021 and 2024. The research, published in Pediatrics, analyzed nearly 20,000 children aged 6 months to 17 years who were tested for influenza at seven pediatric medical centers, offering fresh evidence that the flu shot remains one of the most effective tools for protecting young people from severe illness .

How Effective Is the Flu Vaccine for Different Age Groups?

The vaccine's protective power varied by season and age. During the 2023-2024 flu season, the vaccine prevented 60% of hospitalizations and emergency department visits overall . However, protection was notably stronger in younger children. Kids under 8 years old saw 63% effectiveness during the same season, compared to 48% effectiveness in older children . The vaccine also performed differently depending on which flu strain was circulating.

• Influenza B Protection: The vaccine offered the highest protection against influenza B at 69%, making it the most effective against this particular strain.
• A/H1N1 Protection: Protection against the A/H1N1 strain reached 53%, providing moderate but meaningful defense.
• A/H3N2 Protection: The vaccine was least effective against A/H3N2 at 43%, though still reducing severe illness risk.

These findings are consistent with vaccine effectiveness rates observed before the COVID-19 pandemic, according to researchers.

"Even moderate vaccine effectiveness is translating to a meaningful reduction in flu hospitalizations, emergency department, and doctor's visits for children," said Samantha M. Olson, an epidemiologist in the Division of Influenza at the CDC.

Samantha M. Olson, Epidemiologist, Division of Influenza at the CDC

Why Are Fewer Children Getting Vaccinated?

The study revealed a troubling trend: vaccination rates dropped significantly after the COVID-19 pandemic. Roughly half of the children in the study had been vaccinated each season between 2021 and 2024 . This decline in vaccination uptake has had real consequences. The 2024-2025 influenza season was among the deadliest for children in decades outside of the pandemic, with 280 flu-related deaths reported to the CDC .

Experts point to pandemic-related hesitancy as a key factor.

"Cases of influenza have peaked since less Americans have received the vaccination following the COVID pandemic, a correlation that is no coincidence," said Ravi Jhaveri, division head of infectious diseases at Lurie Children's Hospital of Chicago.

Ravi Jhaveri, MD, Division Head of Infectious Diseases at Lurie Children's Hospital of Chicago

The connection between lower vaccination rates and rising flu cases underscores how critical widespread immunization is for community protection.

What Do Pediatricians Want Parents to Know?

Medical experts emphasize that the flu vaccine's value extends beyond preventing infection altogether. The vaccine significantly reduces disease severity, meaning vaccinated children who do get the flu are far less likely to experience serious complications requiring hospitalization.

"At my hospital every year, we have children who never received a flu vaccine who may die or have a severe illness with several weeks in the hospital. The regret and guilt these parents have is overwhelming," Jhaveri stated.

Ravi Jhaveri, MD, Division Head of Infectious Diseases at Lurie Children's Hospital of Chicago

The American Academy of Pediatrics recommends the influenza vaccine for all children aged 6 months or older . The CDC-funded study included children who received the seasonal flu vaccine at least 14 days before the onset of illness, allowing researchers to measure real-world effectiveness . The findings should help pediatricians reassure parents about the vaccine's proven track record, especially as flu season approaches each year.

With the 2024-2025 season proving particularly deadly for children, experts are urging parents not to delay vaccination. The data make clear that even when the vaccine doesn't prevent infection entirely, it dramatically reduces the chances that a child will end up hospitalized or severely ill.