A new flu strain is causing widespread illness, and it's time to address the big question: Is this year's flu vaccine up to the task?
The influenza A(H3N2) subclade K has earned a reputation as a formidable 'super flu,' rapidly spreading across the nation. With an estimated 180,000 hospitalizations and 7,400 deaths so far this season, according to the Centers for Disease Control and Prevention, it's a serious concern.
But here's where it gets controversial: this particular strain, subclade K, evolved after the vaccine preparation last year. Dr. Adeel Butt, an infectious disease expert, explains, "The vaccine may not fully cover the influenza this year."
The World Health Organization highlights that subclade K viruses have notable genetic differences from related A(H3N2) viruses, which could impact vaccine effectiveness.
However, preliminary data suggests the vaccine is still effective to a significant degree. The UK Health Security Agency reports that the 2025-2026 vaccine is 70-75% effective in preventing hospital attendance for children aged 2-17 and 30-40% effective in adults.
Dr. Daniel Ruderfer, division chief of pediatric infectious diseases at K. Hovnanian Children's Hospital, emphasizes the importance of vaccination: "Those who get the flu vaccines really have better outcomes overall."
And this is the part most people miss: even if the vaccine doesn't fully protect everyone, it's still proven to help prevent serious illness and death. The CDC reports that, on average, vaccines have a 40-60% efficacy in reducing severe illness during flu seasons.
So, while the vaccine may not prevent all infections, it significantly reduces the risk of severe illness and death.
Butt adds, "Vaccination is the best way to protect ourselves and the population against influenza and severe illness related to it."
There's a common misconception that the flu shot can give you the flu, but this is not possible as the CDC-recommended vaccines do not contain active, live virus.
It's important to note that you can still get sick despite receiving a flu shot. This could be due to a different infection or exposure to the virus before the vaccine takes effect, which typically takes about two weeks.
The good news is, it's not too late to get a flu shot. Flu season typically runs from October to May, and currently, nearly 15 states are in the CDC's highest flu activity tier.
Flu vaccines are available for people aged 6 months and older at various locations, including doctor's offices, pharmacies, and community health clinics. Visit the CDC website for more information and to find vaccines near you.
