Abdelrahman
The flu season in the United States is currently at its most intense level in over a decade, with the U.S. Centers for Disease Control and Prevention (CDC) estimating that there have been at least 24 million cases of influenza reported this season.
Approximately 310,000 individuals have required hospitalization due to influenza, and sadly, 13,000 lives have been lost, including 57 children, according to a CDC update on February 7. It’s important to note that this data is preliminary and may be updated as the season advances.
“Influenza is widespread across nearly all parts of the United States,” stated Dr. Robert Hopkins, Jr., the medical director of the National Foundation for Infectious Diseases (NFID). “We are currently experiencing the highest rate of influenza hospitalizations since 2010.”
As of the week ending February 1, 2025, the CDC estimates that 7.8% of health care visits were due to respiratory illnesses, including influenza. This rate has not been seen since the 2009-2010 flu season, with the closest occurrence being in the 2017-2018 season, which peaked at 7.5% of health care visits during the first week of February.
When individuals contract seasonal influenza, often referred to as “the flu,” symptoms typically arise suddenly and may last up to two weeks. However, complications can arise, leading to serious health issues, which can potentially be fatal.
Related: Understanding flu-related fatalities
Influenza can lead to severe conditions such as pneumonia, heart inflammation, organ failure, or sepsis, all of which can be deadly. Those who are more vulnerable include elderly individuals, pregnant women, young children, and those with chronic health conditions like asthma, lung diseases, or kidney problems.
This flu season, respiratory illnesses, particularly influenza, have been increasing in prevalence across the country, exceeding the national baseline for the tenth straight week. According to the CDC, during the week ending February 1, 31.6% of respiratory illness tests conducted in clinical laboratories were positive for influenza, up from 28.5% the prior week, and around 20% earlier in January, compared to under 10% from the start of the season through mid-December.
In the week ending February 1, 10 children were reported to have died from influenza, raising the total number of pediatric fatalities this season to 57.
Out of all 50 states, 32 are currently experiencing “very high” levels of respiratory illnesses, including influenza cases, as reported by CDC statistics. The states most affected include Massachusetts, Michigan, Nebraska, New Hampshire, New Jersey, New Mexico, Ohio, South Carolina, Tennessee, and Texas.
“While it is difficult to predict flu activity and severity, elevated levels of flu activity are to be expected during this period,” noted Paul Prince, a CDC representative, in an email to Live Science.
The severity of a flu season may be influenced by multiple factors, including its start time, community immunity from previous flu seasons and vaccinations, the efficacy of the current year’s vaccine, and the nature of the circulating flu viruses.
According to Hopkins, “The severity of the flu varies annually as the circulating strains undergo changes due to ‘antigenic drift.’ Some strains mutate more significantly, leading to more severe illness in populations with less immunity.”
Human influenza viruses can be categorized into two main types: “A” and “B,” which are further divided into subtypes and variants. Influenza A strains tend to evolve more rapidly than B strains and are associated with more severe disease outcomes.
In a recent analysis of over 4,300 flu samples tested by public health labs by February 1, only 113 were influenza B, indicating that a significant majority were influenza A strains.
Current circulation includes primarily influenza A viruses H1N1 and H3N2, with fewer influenza B viruses, explained Hopkins. He mentioned that the strain characteristics, coupled with low vaccination rates, are likely contributing to the severity of this flu season. He also emphasized that other factors, such as the long-term effects of COVID-19 social distancing measures, are likely not as significant.
Prince also remarked that elevated flu activity is anticipated to continue for several weeks, potentially extending into months. The flu season generally spans from October to May, peaking in February.
It’s not too late for individuals and families to receive the flu vaccine this season,” he advised.
“As long as the flu viruses are active in your area, vaccination remains a viable option,” emphasized Hopkins. “I strongly urge anyone who has not yet received their annual flu shot to do so immediately.”
The CDC advises that everyone over the age of 6 months should receive an annual influenza vaccine.
