Health officials in the United States are sounding the alarm as influenza activity has surged dramatically across the country, with thirty states now reporting 'very high' levels of infection. Experts warn that the severe season is likely to intensify further in the coming weeks.
Dominant Strain Poses Significant Risk
The primary driver of this worrying outbreak is the influenza A H3N2 virus, a strain historically associated with higher rates of hospitalisation and mortality, particularly among older adults. Over 90% of the H3N2 samples analysed belong to a new subclade known as the K variant, which presents a key challenge as it is antigenically different from the H3N2 strain included in this season's flu vaccines.
This mismatch between the circulating virus and the vaccine composition is a serious concern for public health authorities. However, with the traditional peak of the flu season typically occurring in January or February, it remains too early to predict the full impact of this discrepancy on the population's health.
Severe Impact and Rising Hospitalisations
The toll of the early and aggressive flu season is already stark. According to estimates from the US Centers for Disease Control and Prevention (CDC), the nation has seen at least 11 million illnesses, 120,000 hospitalisations, and 5,000 deaths attributable to influenza so far.
The impact on children is particularly concerning. Nine paediatric deaths have been reported, and visits to emergency departments for flu-like symptoms in children have already surpassed the peak observed during the entirety of the last flu season.
Public Health Advice Remains Clear
Despite the concerning variant mismatch, health authorities strongly emphasise that vaccination is still the best defence against severe illness. The CDC continues to recommend that everyone aged six months and older receives their annual flu vaccine. Vaccination can reduce the severity of illness even if a breakthrough infection occurs.
The data, current as of Monday, 5th January 2026, underscores the unpredictable nature of seasonal influenza. With activity spiking over the holiday period and many states now in the CDC's highest tier, the coming month will be critical in determining the ultimate scale of this public health challenge.
