Flu Hospitalizations Surge Nationwide as Cases Rise Rapidly

Flu cases are surging across the United States, leading to a significant rise in hospitalizations and affecting young children particularly hard. The Centers for Disease Control and Prevention (CDC) reported that flu activity is at “high” or “very high” levels in 32 states as of the week ending December 20, 2023. This is an increase from 17 states the previous week. Since the flu season began in October, approximately 7.5 million people have fallen ill, and hospitalizations have nearly doubled in just one week, rising to 19,053 from 9,944. Tragically, around 3,100 individuals have died from the flu this season, with pediatric deaths increasing from two to five within the same timeframe.

Experts warn that the flu season is far from its peak. Dr. Daniel Kuritzkes, a senior infectious disease physician at Mass General Brigham in Boston, noted, “Just looking at the trajectory of the curve, it’s really a pretty sharp increase that we’re seeing, and it’s not anywhere close to peaking or leveling off.”

Current Flu Trends and Affected Demographics

Flu epidemics occur annually in the U.S., typically from October through May, but the current season is progressing more rapidly than usual. New states reporting high flu levels include California, Nevada, Missouri, Arkansas, Alabama, and Florida. States already categorized as “very high” by the CDC, such as New York, New Jersey, South Carolina, Louisiana, and Colorado, are now experiencing even higher rates.

Dr. Jennifer Goebel, an attending physician at South Shore University Hospital in New York, remarked on the unusual timing and volume of cases: “I don’t remember seeing flu cases this early and in this many numbers. It seems worse. Just a tremendous amount of volume.” Dr. Donald Yealy, chief medical officer of the UPMC health system, has observed a “dramatic uptick” in acute respiratory infections, with the majority being suspected influenza cases.

The hardest-hit demographics this season include infants and children up to age four. However, Dr. Lauren Siewny, medical director of the Duke University Hospital Emergency Department in North Carolina, noted that school-aged children and young adults are also increasingly presenting with flu symptoms. Older adults and those with chronic health conditions are more likely to require hospitalization.

Characteristics of the Dominant Strain and Symptoms

The dominant strain this season is Influenza A, specifically a mutated H3N2 strain known as “subclade K.” This strain is believed to cause more severe illness, contributing to the surge in hospitalizations. Dr. Wenqing Zhang, who leads the World Health Organization’s unit for global respiratory threats, acknowledged the genetic changes in the virus but stated that current data do not indicate an increase in disease severity from this new strain.

Symptoms of the flu remain consistent with previous seasons, typically presenting with high fever, chills, cough, shortness of breath, and body aches. Dr. Molly Fleece, an associate professor in infectious diseases at the University of Alabama at Birmingham, emphasized that symptoms can be more severe for unvaccinated individuals and those with underlying health issues. Serious complications including pneumonia and seizures have also been reported.

Doctors urge individuals experiencing severe symptoms, such as persistent high fever or difficulty breathing, to seek medical attention promptly.

The flu vaccine is still recommended, as it includes a component of H3N2, although it may not perfectly match the mutated strain. Dr. Fleece reassured that the vaccine remains effective in preventing severe illness, hospitalization, and death. Dr. Yealy stated, “This year’s seasonal vaccine can help provide protection,” reinforcing the importance of vaccination during this critical flu season.

While the flu is currently the dominant virus, there are rising concerns over Covid-19 infections, which have seen a gradual increase across the country. Data from WastewaterScan, an academic initiative by Stanford University and Emory University, indicates significant Covid levels in the South, Northeast, and Midwest regions. Additionally, there is a noted rise in norovirus infections and respiratory syncytial virus (RSV), particularly in the South.

As the flu season progresses, medical professionals are preparing for the potential overlap of multiple viral infections, which can exacerbate illnesses in patients. Dr. Yealy cautioned, “Having one virus doesn’t actually shun another one off,” highlighting the complexities of managing concurrent respiratory infections during the winter months.