According to recent reports from the CDC, hospitalizations linked to the flu reached the highest levels in over a decade during the 2024-2025 flu season. This alarming trend has emerged ahead of what experts predict could be another severe flu season. Hospitals across the country witnessed an unusually high number of severe flu cases, with nearly 39,000 individuals hospitalized between October and April—a significant increase compared to previous years.
The hospitalization rate during the last flu season was recorded at 127.1 per 100,000 people, more than double the average rate from the past 14 flu seasons. This marked it as the worst season on record since at least 2010. The peak of this severe flu season occurred in early February, where hospitals reported the highest weekly admission rates for flu patients in over a decade. Notably, the overwhelming majority of those hospitalized were unvaccinated, accounting for over 70 percent of admissions.
The clinical outcomes for hospitalized patients were consistent with those seen in past severe flu seasons. Approximately 17 percent of patients required care in the intensive care unit (ICU), while six percent needed a ventilator to assist with breathing. Tragically, three percent of hospitalized patients died during their treatment, although specific death toll figures were not provided. The most common complications observed in patients included pneumonia, sepsis, and kidney failure.
While around 85 percent of hospitalized patients received antiviral medications such as Tamiflu, which are known to reduce the severity and duration of flu illness, treatment rates were notably lower among children and adolescents. This discrepancy may stem from a common misconception among parents who often regard the flu as a mild illness for children, believing their robust immune systems can combat it effectively. However, this is not always the case, as evidenced by the American Academy of Pediatrics reporting 216 flu-related deaths among children last season, marking it as the deadliest non-pandemic flu season for U.S. children.
Each year, scientists affiliated with the WHO and the CDC convene to determine which flu strains should be prioritized in the upcoming season’s vaccine. While the vaccine formula doesn’t always perfectly align with circulating viruses, it generally reduces the risk of doctor visits due to flu by 30 to 60 percent and significantly alleviates the severity of symptoms. To maintain optimal effectiveness, the CDC recommends that everyone aged six months and older receive an annual flu shot, ideally in October.
The effectiveness of the flu vaccine hinges largely on accurate predictions of which viruses will dominate the season. Last season, the CDC estimated the vaccine’s effectiveness at preventing flu-related hospitalizations ranged from 41 percent to 78 percent, while its effectiveness in preventing less severe infections that still required a doctor’s visit varied from 32 percent to 60 percent.
Although most individuals recover from the flu within a few days to a week, the disease remains a serious threat, claiming approximately 36,000 American lives annually. The flu can be particularly dangerous for seniors aged 75 and older, individuals with respiratory conditions like asthma, those with obesity or heart disease, and unvaccinated individuals. Beyond common symptoms like fever, muscle aches, and fatigue, the flu can lead to life-threatening complications such as pneumonia, sepsis, and inflammation of vital organs.
The latest data from the CDC comes from the agency’s surveillance system, FluSurv-NET, which monitors severe flu cases requiring hospitalization across roughly 300 hospitals in 14 states, representing about nine percent of the U.S. population. This system tracks laboratory-confirmed flu cases, providing insights into the demographics and health conditions of hospitalized patients.
For children, asthma emerged as the most significant risk factor for hospitalization, affecting 14 percent of hospitalized toddlers and preschoolers under four years old, and nearly 40 percent of school-aged children and teens aged five to 17. In young adults aged 18 to 49, obesity was the predominant risk factor, impacting about 44 percent of hospitalized individuals in this age group. Among adults aged 50 to 64, chronic metabolic diseases, particularly diabetes, were prevalent, affecting 45.6 percent of hospitalized patients. For seniors, cardiovascular disease was the most significant risk factor, found in 57 percent of adults aged 65 to 74 and an alarming 69 percent of those aged 75 and older.
The 2024-2025 flu season was marked by historically high hospitalization rates, with all age groups experiencing two to three times the hospitalization rates compared to the average of the past 14 seasons. Adults aged 75 and older faced the highest hospitalization rates, with nearly 599 cases per 100,000 people. This season was notably driven by influenza A viruses, particularly the H1N1 strain, which has shown to cause higher hospitalization rates among older adults. For the upcoming flu season, the 2025-2026 vaccine is trivalent, aimed at protecting against three specific strains of the virus. Fortunately, flu shots are typically free with insurance, while public clinics often provide them at no cost. As we approach the next flu season, understanding these trends and the importance of vaccination remains crucial for public health.
