A rapidly spreading strain of flu, known as the “super flu,” is causing alarm across the United States, particularly in New Jersey, where the first pediatric flu death of the season has been reported. The Centers for Disease Control and Prevention (CDC) estimates that there have already been at least 180,000 hospitalizations and 7,400 deaths attributed to the flu this season.
This surge in cases is largely driven by a mutation of influenza A(H3N2) known as subclade K. Analysis reveals that this subclade constitutes 91.5% of the influenza A(H3N2) viruses subjected to further testing by the CDC. Flu viruses are known for their constant mutations, making it difficult for health officials to predict which strains will dominate each season, thus complicating vaccine development.
Dr. Adeel Butt, an infectious disease expert at JFK University Medical Center, noted that the current vaccine was formulated in February 2025, while subclade K only emerged later in August of that year. This discrepancy between circulating viruses and vaccine-targeted strains results in decreased vaccine effectiveness. The World Health Organization (WHO) acknowledges that while subclade K represents a significant evolution in influenza A(H3N2) viruses, current data does not indicate an increase in the virus’s severity.
Despite these concerns, preliminary data suggests that the current flu vaccine remains effective, especially in lowering hospitalization rates. The UK Health Security Agency reports that the 2025-2026 vaccine is 70-75% effective at preventing hospital attendance among children aged 2 to 17 and 30-40% effective in adults. Dr. Daniel Ruderfer from K. Hovnanian Children’s Hospital confirms that vaccinated individuals tend to have better health outcomes, with unvaccinated children being more likely to experience severe flu symptoms.
However, there is a troubling trend of declining flu vaccination coverage among children, dropping from 55.4% last season to just 49.2% this year. The CDC indicates that as of late December 2025, only 42.5% of children aged 6 months to 17 years had received their flu shots—the lowest coverage since 2011.
Public health experts emphasize the importance of vaccination as the primary defense against influenza and its severe complications. Despite misconceptions about the flu vaccine causing illness, Dr. Butt clarifies that the vaccines do not contain live viruses, thus cannot transmit the flu. They work by introducing viral proteins or inactivated viruses to help the immune system prepare for potential infections.
While there are still opportunities to get vaccinated, flu season is far from over, with the CDC noting that the peak flu activity typically persists until May. Vaccines are available for individuals aged six months and older at various healthcare locations, including pharmacies and community health clinics. The ongoing flu season underscores the importance of vaccination and the need for continued public awareness and health safety measures.