Locator: 49930FLU.
Updates
From CDC, Week Ending January 10, 2026
Link here.
Summary:
- most frequently reported influenza virus this week: A(H3N2) --- in other words, subclade K;
- outpatient respiratory illness: dropped 5.3% week/week;
- cumulative rate of hospitalization per 100,000 population: 50.4;
- pediatric deaths: 15 this past week; a total of 32 deaths this season;
- significant drop since last week; this is the first wave; dropped faster and earlier than last year;
- US map looks pretty good;
- graphs and graphics to follow;
- data can be updated as reports roll in for the past week.
To put this in perspective, the rate for last season (2024 - 2025) was 127, see below (reminder, the rate of 50 reported above is for only the early part of the season this year; we have the second wave yet to hit; neither wave is consistently the worse wave; it depends on the circulating virus):
Pediatric deaths last season (2024 - 2025):
Clinical testing, typing, subtyping (I'm always amazed how few samples are collected; and even fewer analyzed):
Original Post
From CDC, Week Ending January 3, 2026
Purposely asked the "wrong" question (sometime asking a chatbot the "wrong" question can lead to a better answer):
AI prompt: what subclade is A/H1 -- HA subclade D.3.1. Is it subclade K?
AI answer:
From the weekly CDC report (last week; a new report should be released today), link here:
Of the 691 specimens typed:
- 193 specimens were A/H1
- 436 specimens were A/H3
- of these 436 specimens (A/H3); 399 specimens were subclade K
- 62 specimens were B/Victoria
- 0 specimens were B/Yamagata
So, 292 / 691 or 42% were not subclade K. The bad news: folks can get multiple types of flu A (flu B) and any given season, and, even worse, can get multiple types of flu simultaneously.
In other words, at the end of the day, if you are diagnosed with influenza A this season, it's very, very likely it will be subclade K. Subclade K "evolved" after this year's influenza vaccine was already developed and distributed, and came too late in the season for a subclade K vaccine to be developed.
