Flu season is surging nationwide, with cases rising rapidly in recent weeks. Children have been the hardest hit, and experts warn that older adults may be next as the holidays approach.
“We’ve seen sustained, elevated activity across multiple indicators in many areas,” said Alicia Budd, head of the CDC’s domestic influenza surveillance team.
The CDC reported Friday that this season has already caused at least 4.6 million illnesses, more than 49,000 hospitalizations, and 1,900 deaths. Young children, ages 0 to 4, have been affected the most.
Evidence points to an early and aggressive flu season. From November to December, influenza type A concentrations in wastewater rose 390 percent nationwide, according to WastewaterSCAN, a program from Stanford University and Emory University.
“This upward trend is increasing very consistently,” said Marlene Wolfe, program director for WastewaterSCAN. “We’re not seeing any sign of plateauing yet.”
Dr. Chase Shutak, medical director of Children’s Minnesota, said positive flu cases at his facility doubled last week.
Flu symptoms vary. “In some years, every child with the flu looks miserable, dazed, with that classic glassy-eyed appearance,” Shutak said. “This year, some kids show milder symptoms but still come in because they are disruptive or uncomfortable.”
Influenza A, specifically H3N2, dominates this season. While anyone can get it, H3N2 causes more hospitalizations and deaths in older adults. Experts worry that sick children could spread the virus to grandparents and other older family members during holiday gatherings.
“With schools on break and families mixing, viruses can move from school-age children to older populations,” Budd explained.
Where Is the Flu Spreading?
The CDC reports high or very high flu activity in 14 states, including Colorado, Idaho, Louisiana, Michigan, New Jersey, and South Carolina, as well as in New York City, Washington, D.C., and Puerto Rico.
Flu can be deadly even when it isn’t widespread. For example, Wisconsin reported its first pediatric flu death of the season, despite minimal activity overall. North Carolina also reported its first child death on Wednesday.
These recent deaths likely aren’t counted in the CDC’s latest report, which included three pediatric deaths through Dec. 13. The CDC will release its next flu update on Dec. 30.
The 2024-2025 flu season was particularly deadly for children. Last year, 288 children died of flu, tying a record set during the 2009-2010 H1N1 pandemic. A CDC report showed that half of these children were otherwise healthy, and 89 percent had not received the flu vaccine.
Will the Flu Shot Work This Year?
Flu vaccines rarely match circulating strains perfectly. This year, a new H3N2 subclade called K has emerged, altering the virus’s surface protein.
The body recognizes the virus by its surface protein. Even a slight change can reduce immunity. Budd said it’s difficult to predict the vaccine’s exact effectiveness, but it still protects against H3N2 generally.
“We’ve seen drifted viruses in past seasons. Sometimes the vaccine effectiveness drops, but other times it continues to provide protection,” she said. Budd stressed that everyone, including children, should get the flu shot. “It remains the primary preventive measure against flu and severe illness.”
Demand for Tamiflu, an antiviral treatment, is slightly higher than at the same time last year, according to GoodRx. People usually receive prescription antivirals only when sick enough to see a doctor, not just from a positive test.
“What stands out this season is how early Tamiflu use is climbing,” said Tori Marsh, senior director of research for GoodRx. “When prescription antiviral use rises sooner than average, it often signals that flu activity is starting earlier and may last longer.”
