Flu activity across the United States has reached high levels, with significant increases in reported illnesses, hospitalizations, and pediatric deaths. The Centers for Disease Control and Prevention (CDC) estimates for the current season, as of the week ending January 10, include at least 18 million illnesses, 230,000 hospitalizations, and 9,300 deaths, with 32 pediatric fatalities reported. This elevated activity occurs as federal health agencies have adjusted recommendations for childhood flu vaccination and Medicaid immunization data reporting.
Current Flu Activity and Trends
Influenza infections increased during the holiday period, with 45 states reporting high or very high flu activity by the week of Christmas, rising from 30 states the prior week. As of December 27, 48 U.S. jurisdictions reported high or very high levels. By the week ending January 3, 2026, over half of U.S. states were classified as having "high" or "very high" flu rates. The most recent data from the week ending January 10 indicates 26 states reported "very high" levels and 16 states reported "high" levels of flu-like illnesses.
Outpatient visits for flu-like illnesses (ILI), characterized by fever, cough, or sore throat, reached levels not observed since 1997. Approximately 8.2% of outpatient doctor's visits were for ILI around late December. Children have been disproportionately affected, with more than 18% of visits for children under four years old being flu-related, marking the highest level since at least 2016. Roughly 35% of all outpatient ILI visits occurred among individuals under 24 years old, with children under age five accounting for approximately 20%.
While national data for the week ending January 10 showed an over 18% reduction in confirmed flu cases, a more than 5% decrease in doctor visits for respiratory illnesses, and a nearly 55% reduction in hospitalization rates, experts advise caution in interpreting this as a peak. This temporary decline may be attributed to changes in healthcare-seeking behavior and reporting during the holiday period, with expectations for activity to rebound. Flu activity often extends into the spring, and the season typically peaks in January or February.
Regional variations exist, with states like Idaho, New Mexico, New York, and parts of Appalachia experiencing very high levels of flu, while Montana, South Dakota, Vermont, and Wyoming reported low case numbers in mid-January. New York state health officials documented the highest number of flu hospitalizations recorded in a single week.
Seasonal Statistics and Impact
As of the week ending January 10, the CDC estimates the current season has resulted in:
- At least 18 million illnesses
- 230,000 hospitalizations
- 9,300 deaths
- 32 pediatric flu deaths
Hospitalizations saw approximately 40,000 new flu-related admissions for the week ending January 3, a 10% increase from the prior week. The national flu hospitalization rate was about 12 per 100,000 people. Seniors remain the demographic group most frequently hospitalized, though hospitalization rates among children are also elevated. Four of the pediatric deaths reported by early January occurred in Massachusetts, including two children under the age of two in Boston. In Georgia, 46 flu-associated deaths were confirmed between October 2025 and January 3, 2026.
Last flu season (2024-2025) recorded 289 child flu deaths, the highest number since CDC tracking began in 2004, and exceeding the 2009 H1N1 flu pandemic.
Dominant Flu Strain and Vaccine Effectiveness
The current rise in cases is attributed to the prevalence of the Influenza A H3N2 virus. Analysis indicates that over 90% of the H3N2 infections identified are a subclade K variant. This subclade K variant has been in circulation internationally since the summer and is considered a new variant. It differs from the specific H3N2 strain included in this year's influenza vaccines, contributing to what experts describe as a "slight mismatch" between the prevalent circulating strain and the vaccine formulation.
Despite this mismatch, health officials emphasize that vaccination remains a critical measure. The vaccine targets two influenza A subtypes (H1N1 and H3N2) and one influenza B subtype. While it may not prevent all infections, it can mitigate illness severity, reduce the likelihood of hospitalizations, and prevent other severe complications. Studies suggest that even with a mismatch, vaccinated individuals are less likely to experience severe outcomes. For instance, a study published in "Clinical Infectious Diseases" indicated that vaccinated adults aged 65 and older were 52-79% less likely to die compared to unvaccinated hospitalized patients.
As of late December, approximately 43.5% of adults aged 18 and older and 42.5% of children had received a flu vaccine. Approximately 130 million doses of the flu vaccine have been distributed nationwide this season.
Federal Vaccine Recommendations and Policy Changes
The Department of Health and Human Services (HHS), under Health Secretary Robert F. Kennedy Jr., announced a change in policy, no longer recommending flu vaccinations for all U.S. children. This decision states that the choice should be made by parents and patients in consultation with their doctors. The administration had previously ceased recommending COVID-19 shots for healthy children last year.
The CDC subsequently updated its recommended childhood vaccine schedule to suggest "shared clinical decision-making" with healthcare providers for non-high-risk children regarding flu vaccination, rather than a universal recommendation. The CDC also dropped the routine recommendation for six other childhood immunizations. This policy shift has raised concerns among some medical professionals, who noted its timing during a severe flu season and suggested it could lead to confusion for families or a reduction in childhood vaccination rates. Acting CDC Director Jim O'Neill stated that pediatric flu vaccination decisions should be based on individual patient characteristics.
Flu vaccines continue to be covered by private insurers and federal programs, including Medicaid, the Children's Health Insurance Program, and the Vaccines for Children program.
In a separate but related development, a federal notice issued last week indicated that government Medicaid programs will no longer be required to report on immunization rates. Health Secretary Robert F. Kennedy Jr. stated this change is part of an initiative to separate the rating and payment of Medicaid doctors from their childhood vaccination rates, commenting that government entities should not "coerce doctors or families into accepting vaccines or penalize physicians for respecting patient choice." Medical directors have expressed concern that this change eliminates a significant data source for assessing efforts to protect children from vaccine-preventable diseases.
Co-circulating Viruses and Prevention
In addition to influenza, COVID-19 infections have also been rising this winter, though they remain less frequent than flu cases. Respiratory syncytial virus (RSV) is also circulating, with all three viruses (flu, COVID-19, RSV) appearing to peak concurrently this year, contributing to overall respiratory illness activity.
Health officials continue to advise the public on preventive measures, including thorough handwashing, wearing masks in crowded indoor environments, avoiding contact with sick individuals, limiting contact with high-touch surfaces, and staying home if experiencing flu symptoms. Vaccination is recommended for individuals aged 6 months and older who have not yet received this season's influenza vaccine.