Health officials across the United States are raising the alarm as cases of a potent new influenza strain surge 'skyrocketing' weeks earlier than the typical seasonal peak. The concerning wave, arriving ahead of the usual holiday spike, is largely attributed to a dangerous new flu variant known as H3N2 subclade K.
Early Surge and Widespread Impact
According to the latest CDC figures from the week ending December 6, influenza transmission has reached 'very high' levels in New York City, with 'high' activity reported in the surrounding states of New Jersey and New York. Colorado and Louisiana are also reporting 'high' levels, with 'moderate' activity noted in Idaho and Connecticut.
The strain is now circulating in more than three dozen states. Nationwide, 8.1% of flu tests were positive during the week of December 6, a rise from 7.1% the previous week. This time last year, the positivity rate stood at 5.1%.
The early and severe impact is already disrupting daily life. In Brooklyn, Poly Prep Country Day School was forced to close its Dyker Heights campus for two days after at least 200 students were absent or sent home with flu-like symptoms.
Similar measures were taken at Villa Duchesne Catholic School in St Louis, Missouri, and the Moulton-Udell school district in Iowa, where nearly 30% of students and staff fell ill, leading to cancelled classes and sports.
Hospitalisations Rise and Protocols Return
The strain's severity is reflected in rising hospital admissions. The CDC reports the national influenza hospitalisation rate has jumped to 6.9 per 100,000 people, up from 4.3 per 100,000 the week before. For comparison, the rate was 3.1 per 100,000 at this point in 2022.
Texas health officials reported the week ending December 6 was the third consecutive week to surpass 5,000 hospital and clinic visits for flu-like illness—double the amount seen last year. Alarmingly, hospitalisations for those over 65 in Texas reached 7.4 per 100,000, up from 2.2 per 100,000 in November.
In response, healthcare systems are reinstating protective measures. Major networks in New Jersey, including Hackensack Meridian Health and RWJ Barnabas Health, have brought back mandatory masking for patients, visitors, and staff. Detroit Medical Center has also restricted visitor access to curb the virus's spread.
Public Health Urges Vigilance and Vaccination
New York City's acting health commissioner, Dr Michelle Morse, described the city's case numbers as 'skyrocketing' and strongly urged residents to get their annual flu shot. She also advised wearing a mask if symptoms develop.
This year's dominant H3N2 strain is new to most people's immune systems, increasing vulnerability and the risk of severe illness requiring hospitalisation. Public health officials stress watching for typical flu symptoms, which come on abruptly and can include:
- Fever and chills
- Fatigue and body aches
- Headache
- Cough, congestion, and runny nose
While the severity indicators for the season currently remain low, the CDC warns activity is increasing in most areas. The flu virus's unpredictability makes it unclear if H3N2 will remain dominant or become more severe.
The seasonal flu vaccine, which is typically 40-60% effective, remains the best defence against Influenza A, which accounts for three in four current cases. So far this season, an estimated 3 million people have contracted the flu, resulting in 1,200 deaths.
