A potent new strain of influenza, dubbed a 'super flu', is spreading at an alarming rate across the United States, forcing hospitals to reintroduce Covid-era restrictions such as mask mandates and visitor limits.
Unprecedented Spike in Cases and Hospitalisations
The latest data from the US Centers for Disease Control and Prevention (CDC) paints a stark picture. For the week ending December 20, 2025, positive flu tests surged by 53 percent compared to the previous week. This figure is nearly 75 percent higher than at the same point last year.
Hospital admissions tell an even more concerning story. The number of people hospitalised with flu jumped by 51 percent in that single week. Critically, the hospitalisation rate has nearly doubled compared to the same period in 2024.
Transmission is now classed as 'very high' in 21 states. The areas hardest hit include New York City, New York state, New Jersey, South Carolina, Louisiana, and Colorado. In New York alone, officials recorded over 71,000 cases last week – the highest weekly total the state has ever seen.
A New Strain and Tragic Consequences
Experts attribute the meteoric rise to a new flu strain, H3N2 subclade K. This year's dominant variant is brand new to people's immune systems, leaving the population highly vulnerable and at increased risk of severe illness requiring hospital treatment.
The human cost of the surge is already devastating. In the last week, two children – one in Kentucky and one in Alabama – have died from flu complications. 14-year-old Noah Smothers from Alabama passed away on Monday. His heartbroken family described him as their "best friend" and "brother".
So far this flu season, the CDC estimates there have been at least 7.5 million illnesses, 81,000 hospitalisations, and 3,100 deaths, including eight paediatric fatalities.
Hospitals React with Stringent Measures
In response to the crisis, healthcare institutions are swiftly enacting protocols not widely seen since the height of the Covid-19 pandemic. The goal is to slow the spread within vulnerable hospital populations.
Duke Health in North Carolina will limit visitors to just two people aged 12 and over per patient starting January 6, 2026. Similarly, Iredell Memorial Hospital, also in North Carolina, has immediately banned all visitors under the age of 14.
Medical experts are urging the public to remain vigilant. Dr Neal Shipley of Northwell Health-GoHealth Urgent Care warned that symptoms in children can appear suddenly and may include vomiting and diarrhoea. Those over 65 are at the highest risk of severe complications.
"If your symptoms worsen quickly, or you have trouble breathing, weakness, dehydration or symptoms that don’t improve after a few days, you should find your nearest urgent care," Dr Shipley advised.
With the flu season typically peaking between December and February, officials fear the worst may be yet to come. Virologist Andrew Pekosz of Johns Hopkins University told NPR: "When you're in the middle of seeing the curve start to go up, we just don't have any sense of where it's going to stop."
The CDC reports that only about 40 percent of American adults have received this season's flu vaccine, which is estimated to be 30 to 75 percent effective against the circulating strains.
