Hospital admissions linked to a potent seasonal influenza strain, dubbed the 'super flu', have skyrocketed across the United States, with older adults and young children bearing the brunt of the severe outbreak.
Fresh data from the US Centres for Disease Control and Prevention (CDC), covering the week ending 3 January, shows a dramatic 53% increase in weekly flu-related hospitalisations compared to the previous week. The surge is largely attributed to the H3N2 subclade K virus strain.
Sharp Rise in Cases Among Vulnerable Groups
The overall hospitalisation rate for the season has also climbed by 37% week-on-week. This translates to nearly 40,000 Americans being admitted for flu in a single week, a significant jump from 33,000 the week prior.
The increase has disproportionately affected Americans aged over 50. Since the flu season began in October, hospitalisations in this age group have surged by a staggering 157%. Outpatient visits for over-50s also rose by 51% compared to late December.
Residents in retirement homes and long-term care facilities are being hospitalised at an alarming rate, with a 53% increase reported in the last week alone.
While doctor visits among young children are declining, they still accounted for the largest share of flu-related outpatient visits at nearly 20%. Their underdeveloped immune systems make them particularly vulnerable.
Tragic Paediatric Deaths Highlight Severity
The human cost of the outbreak is becoming tragically clear. Overall flu-related deaths increased by 70% in the last week, rising from 0.9% to 1.9% of cases.
The CDC reported eight paediatric flu deaths during the week of 3 January, bringing the season's total to 17. Among them was two-year-old Isaias Castillo IV from New Jersey, who died on 6 January from complications of the flu, as announced by his family.
Acting New Jersey Health Commissioner Jeff Brown stated: 'This flu season is already shaping up to be a very serious one, with more cases than previous years and, tragically, one child’s death this week.' He urged vaccination to help reduce spread and prevent serious complications.
This warning follows a controversial national policy shift announced by Health and Human Services Secretary Robert F Kennedy Jr, which will no longer recommend annual flu vaccines for all children—historically the best preventative measure, with an efficacy between 30 to 75%.
Regional Impact and Strain Characteristics
Weekly hospitalisations have risen from 31.3 to 54.1 per 100,000 people. The cumulative season rate increased from 28.1 to 40.6 per 100,000.
There are some tentative signs of slowing transmission. Test positivity has begun to decline, and the number of states reporting 'very high' influenza activity dropped from 34 to 27. However, 14 states, including New York, New Jersey, and Georgia, remain at the CDC's highest activity level.
Experts warn this season's dominant H3N2 strain is new to most people's immune systems, increasing the risk of severe illness. Symptoms, while similar to other flu strains, are leading to more serious outcomes, especially in children, featuring week-long fevers and coughs that cause breathing difficulties.
One severe case involves two-year-old Sarah Lopez from Georgia, hospitalised for weeks after a flu infection led to transverse myelitis, a rare spinal cord inflammation. She required a ventilator and feeding tube and is now in rehabilitation.
Dr Neal Shipley, a medical director, advised the public to seek urgent care if symptoms worsen quickly, or if they experience trouble breathing, weakness, or dehydration.
