Recent data from the U.S. Centers for Disease Control and Prevention (CDC) indicates that flu cases are climbing nationwide during the holiday travel and gathering season, with the infection rate increasing faster than in previous years. Estimates released on Tuesday show that at least 7.5 million people have fallen ill this season so far, resulting in 81,000 hospitalizations and 3,100 deaths, with experts warning that these numbers are likely to continue rising. Public health experts cited holiday travel, low vaccination rates, and misinformation as key contributors to the surge in cases. Of the 275 viruses collected since September 28, 2025, 89.5% belong to the K subclade, a variant of the influenza A (H3N2) virus. Andrew Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health, noted that a significant factor this flu season is the rapid emergence of cases once the virus enters a state or geographic region. He added that some experimental data and genetic sequencing also suggest the virus appears to have mutations that may help it evade immunity in certain populations. According to the CDC, more than 19,000 flu patients were admitted to hospitals in the week ending December 20, an increase of approximately 10,000 from the previous week. Five pediatric flu-related deaths were reported last week, bringing the total number of deaths for the 2025-26 flu season to eight. Daniel Kuritzkes, an infectious disease specialist at Brigham and Women's Hospital in Massachusetts, stated, "This could be a much more severe flu season than what we've seen in recent years, though so far there's no evidence that the illness is more severe on a per-patient basis." While severity indicators remain low, the CDC report predicts that flu activity is expected to continue for several more weeks. The agency urged everyone aged six months and older who has not yet received a flu vaccine to get vaccinated. Experts also emphasized that even though there is a mismatch between the vaccine and the circulating strain, people should still get vaccinated, as it can induce antibodies that recognize new variants and help mitigate illness. Eric Asher, a family medicine physician at Northwell Health's Lenox Hill Hospital, explained, "We know the vaccine isn't a perfect match for this strain because the flu virus has undergone some mutations." The CDC reported that approximately 130 million doses of the flu vaccine have been distributed nationwide this season. Cameron Wolfe, a professor at Duke University, cautioned, "All the socializing during the holidays will inevitably increase transmission, and we haven't yet seen cases begin to decline."