12/10/2025
It's impossible to listen to the news or read anything online and not see that this is going to be a difficult influenza season. Reports from the United Kingdom indicate that they are already having a high rate of infection and we use that information as an indicator of what our flu seasons will look like this year. Already we are seeing pockets of influenza throughout the US, although so far, locally we are not seeing much if any. When you look at the various types of Influenza it can look like an alphabet soup of initials and numbers that make absolutely no sense to the lay person.
In general we categorize influenza into Influenza A or Influenza B, with A being the most common. There are subtypes within each category that include H1N1, H3N2, and H3N2K. Each year researchers take their best guess based on data to determine what viruses will be circulating 9 months from the development of the flu vaccine. This year's vaccine contains Influenza A H1n1 and H3N3 and Influenza B- Victoria Lineage. Unfortunately, these viruses are smart little bugs and will mutate to a new version of themselves. This year we are seeing the H3N3 mutate to a K version.
The complication of a mutated virus is two-fold. First it has changed since the vaccine was first developed so it is not covered under the vaccine. Secondly, this is a version of the virus that our body has not seen, so we have no natural immunity to it. This means that it is more likely to make more people sick and to travel from person to person with ease. Currently we are seeing pretty widespread outbreaks of H3N3 - K.
What does this mean to the average person? Not much. Even as a clinician we don’t try to determine what subtype of Influenza you have because it doesn’t change how we are going to treat you. People with Influenza develop a rapid onset of symptoms (felt great one minute and hit by a mack truck the next) that include body aches, fever, headache, sore throat cough and extreme exhaustion. Often kids will have vomiting and diarrhea as well, adults not so much. The basic treatment is rest, fluids and Over the counter medications to treat your symptoms. There are antiviral medications that must be administered within 48 hours of the onset of symptoms and will shorten the average course of the illness by 1-2 days. These are really only beneficial for those who are immune compromised or have other conditions that can be significantly worsened by the flu.