At a Glance
- 32 states report high or very high flu activity
- Hospitalizations jumped to 19,053, double the previous week
- Pediatric deaths rose to five, up from two
- Why it matters: The surge strains hospitals and signals a prolonged flu season.
Flu cases have surged across the United States, with the CDC reporting activity at “high” or “very high” levels in 32 states and jurisdictions for the week ending Dec. 20. At least 7.5 million people have fallen ill since the season began in October.
Hospitalizations nearly doubled in a single week, rising to 19,053 from 9,944 the week before, while 3,100 deaths have been attributed to flu this season. Pediatric deaths climbed to five, up from two the prior week.
Dr. Daniel Kuritzkes stated:
> “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.”
New states reporting high levels include California, Nevada, Missouri, Arkansas, Alabama, and Florida. States already in the CDC’s “very high” category-New York, New Jersey, South Carolina, Louisiana, and Colorado-now sit at the top end of the range.
Strain, Symptoms, and Vaccination
The dominant strain this season is Influenza A, specifically a fast-spreading, mutated H3N2 subclade K that some call the “super flu.” The strain emerged over the summer and carries changes to a key surface protein, making it harder for the immune system to recognize.
Dr. Wenqing Zhang wrote:
> “Although the genetic shift makes a notable evolution in the virus, current data don’t suggest an increase in disease severity from the new strain.”
Symptoms remain largely the same as previous seasons: high fever, shaking, chills, cough, shortness of breath, and muscle aches. Unvaccinated individuals and those with underlying conditions report more severe complications such as pneumonia, muscle breakdown, and seizures.
Dr. Molly Fleece noted:
> “Symptoms start acutely, and people have higher fever, shaking, chills, cough, shortness of breath and muscle aches. Symptoms can be more severe, especially if a person is unvaccinated.”
Patients also report headaches, fatigue, nausea, vomiting, and diarrhea. Those with persistent shortness of breath or high fever despite over-the-counter medication should seek medical attention.
| Metric | Current Week | Previous Week |
|---|---|---|
| Hospitalizations | 19,053 | 9,944 |
| Pediatric deaths | 5 | 2 |
The current flu shot contains an H3N2 component but does not perfectly match the mutated strain. Nevertheless, the vaccine remains highly effective at preventing severe illness, hospitalization, and death.
Dr. Donald Yealy explained:
> “This year’s seasonal vaccine can help provide protection, essentially arming your body with the appropriate response before you get infected.”
Other winter viruses are also circulating. Covid cases are slowly rising nationwide, with high levels in the South, Northeast, and Midwest. Norovirus infections spiked in late November and continue to rise, while RSV is starting to take off, especially in the South.
Dr. Lauren Siewny added:
> “We have built-in plans for these surges, and we prioritize the sickest patients first.”
Key Takeaways
- Flu activity is at high levels in 32 states, with hospitalizations doubling.
- Pediatric deaths have risen to five, a significant jump from two.
- The mutated H3N2 strain is the dominant virus, but the current vaccine still protects against severe outcomes.
The ongoing flu surge, combined with other winter viruses, will keep hospitals on alert well into the new year.
