A Slow Start with Underlying Concerns
The United States is experiencing a slow start to its flu season, with health officials uncertain if it will reach the severe levels witnessed last winter. However, data released on Friday by the U.S. Centers for Disease Control and Prevention (CDC) has revealed a significant development: the emergence of a new version of the flu virus.
The New Strain and Vaccine Effectiveness
CDC data indicates that this new variant, a subclade K of the type A H3N2 virus, has been the main driver of recent infections. Historically, H3N2 strains are associated with higher rates of hospitalisation and death, particularly among older individuals.
An early analysis from the United Kingdom offers a glimmer of hope, suggesting that the current seasonal vaccines may still provide at least partial protection against this new version. Scientists stress that any protection which lessens the severity of a flu infection is crucial, though it will take more time to determine the exact effectiveness.
Alicia Budd of the CDC confirmed that flu activity is currently low nationwide, with only Louisiana reporting moderate levels. Most infections detected so far have occurred in children.
Vaccination Rates: The Critical Factor
Beyond the new strain, a primary worry for scientists and medical professionals is the disappointing rate of vaccination. This was a key reason why the previous flu season was one of the deadliest this century.
Last winter saw the highest flu hospitalisation rate since the H1N1 pandemic 15 years ago. Flu was identified as the underlying or a contributing cause in over 18,000 deaths. In a particularly severe week early this year, more than 1,800 flu-related deaths were recorded—the highest one-week spike in at least a decade. Child flu deaths were also far above usual levels.
Asefeh Faraz Covelli of the George Washington University School of Nursing expressed grave concern, stating, "I think we’re going to see a really severe season." She warned that illnesses are likely to accelerate as people travel and gather for Thanksgiving, adding, "This is the ideal time to get vaccinated."
Current vaccination data presents a mixed picture. For COVID-19, rates are plummeting, with only about 6% of children and 14% of adults up to date on their shots. For the flu, the CDC's survey data indicates the child vaccination rate is holding steady at 34%, while the adult rate has increased slightly to around 37%. However, data from IQVIA, a health research company, showed that over two million fewer flu shots were administered in US pharmacies through October compared to the same period last year.
Compounding these challenges, researchers have faced difficulties tracking trends due to a recent government shutdown that halted CDC data collection. Furthermore, public health messaging has been impacted since U.S. Health Secretary Robert F. Kennedy Jr., a prominent anti-vaccine activist, took charge of federal health agencies, fostering uncertainty about vaccine safety.
As of early November, flu hospitalisation rates are similar to the same point in 2024. Thankfully, rates for COVID-19 and RSV are lower so far this season. With the peak flu period typically occurring between December and February, the window for protective action is now.
