The United States is currently grappling with its most severe flu season in over a decade.
The Centers for Disease Control and Prevention (CDC) estimates that, as of February 7, 2025, there have been at least 24 million influenza cases nationwide.
This surge has led to over 310,000 hospitalizations and 13,000 deaths, including 57 children.
These preliminary figures are subject to change as the season progresses.
Dr. Robert Hopkins, Jr., medical director of the National Foundation for Infectious Diseases (NFID), emphasizes the widespread impact: “Influenza is widespread across most of the U.S.
We are currently seeing the highest level of influenza hospitalizations since 2010.”
Escalating Healthcare Visits
For the week ending February 1, 2025, approximately 7.8% of healthcare visits were due to respiratory illnesses such as influenza.
This percentage hasn’t been this high since the 2009-2010 season, which peaked at 7.5% in early February.
Influenza symptoms typically appear suddenly and can last up to two weeks.
While many recover without complications, the infection can lead to severe health issues, including pneumonia, heart inflammation, organ failure, or sepsis, all of which can be fatal.
Those at higher risk include older adults, pregnant individuals, young children, and people with chronic medical conditions like asthma, lung disease, or kidney disorders.
Nationwide Impact
Respiratory illnesses, including influenza, have been increasing nationwide, remaining above the national baseline for the tenth consecutive week.
During the week ending February 1, the CDC reported that 31.6% of respiratory illness tests conducted by clinical labs returned positive for influenza.
This is a significant increase from 28.5% the previous week and below 10% from the start of the flu season until mid-December.
Tragically, ten children were reported to have died from the disease in the week ending February 1, bringing the season’s total to 57 pediatric deaths.
Out of 50 U.S. states, 32 currently have “very high” levels of respiratory illness, including influenza cases.
The highest levels are being reported in Massachusetts, Michigan, Nebraska, New Hampshire, New Jersey, New Mexico, Ohio, South Carolina, Tennessee, and Texas.
Factors Contributing to Severity
Paul Prince, a CDC spokesperson, notes that while flu activity and severity cannot be precisely predicted and can vary from season to season, elevated flu activity is expected at this time of year.
The severity of a flu season can depend on several factors, including the timing of its onset, the public’s pre-existing immunity from prior flu seasons and vaccinations, vaccine uptake and effectiveness, and the characteristics of circulating flu viruses.
Dr. Hopkins explains that flu severity varies annually as strains in circulation change through a process called “antigenic drift.”
Some strains mutate more than others, and those that do—and for which the population has less immunity—cause more severe disease.
Human influenza viruses are categorized into two broad types: “A” and “B,” which are further divided into subtypes and variants.
Influenza A variants tend to change more rapidly than influenza B and often cause more severe disease.
The CDC reports that, of more than 4,300 flu specimens tested by public health laboratories in the week ending February 1, only 113 were influenza B, with the remainder being influenza A.
Dr. Hopkins notes, “We are currently seeing widespread circulation of influenza A H1N1 and A H3N2 viruses primarily, with less circulation of influenza B viruses.”
He suggests that the characteristics of these strains, combined with low vaccination rates, are likely responsible for the severity of this flu season.
Vaccination Rates and Public Health Response
Vaccination rates have remained suboptimal, with approximately 44% of adults receiving flu shots this winter, mirroring last year’s figures.
However, coverage among children has declined to about 45%, down from the usual 50%.
This decrease in vaccination uptake may contribute to the heightened severity of the current flu season.
Health officials continue to emphasize the importance of vaccination.
Prince adds that elevated flu activity is expected to continue for weeks and possibly months.
Flu season typically runs from October to as late as May, peaking in February.
“There’s still time for individuals and families to benefit from the flu vaccine this season,” he says.
Dr. Hopkins emphasizes, “As long as flu viruses are circulating in your community, it is not too late to get vaccinated.
I strongly encourage anyone who has not yet received an annual flu vaccine to do so immediately.”
Impact on Healthcare Systems
The surge in flu cases has placed significant strain on healthcare systems across the country.
Hospitals are experiencing increased admissions, leading to longer wait times and resource shortages.
In some regions, elective procedures have been postponed to accommodate the influx of flu patients.
Healthcare workers are also feeling the pressure, with many facilities reporting staffing challenges due to illness among medical personnel.
This situation underscores the importance of preventive measures, including vaccination, to reduce the burden on healthcare infrastructure.
Preventive Measures and Public Guidance
In addition to vaccination, public health officials recommend several measures to mitigate the spread of influenza:
- Hand Hygiene: Regularly wash hands with soap and water for at least 20 seconds.
- Respiratory Etiquette: Cover coughs and sneezes with a tissue or the inside of your elbow.
- Avoiding Close Contact: Stay away from individuals who are sick, and if you are ill, limit contact with others to prevent transmission.
- Surface Cleaning: Regularly disinfect frequently touched objects and surfaces.
- Stay Home When Sick: If you exhibit flu-like symptoms, remain at
