Thread by @HelenBranswell

1. A #flu 🧵:
Activity continued its sharp decline in the week ending Jan 21. It's barely over the epidemic threshold at this point nationally; in 6 regions it's below it. But for the fact that we've seen little #fluB activity, it would be tempting to guess flu season is over.

2. But virtually all — 99.5% — of the #flu activity so far this season has been caused by flu A. There hasn't been much flu B since the first half of the 2019-20 season. In the Before Times, it was common to see flu B in late winter, early spring. This year? Ask me in June.

3. This #flu season took off like a bat outta hell in October, peaking Thanksgiving week. Activity reached a high apex, but the drop off has been swift. The image on the left shows #influenza-like illness the week ending Jan. 7. On the right, the week ending Jan. 21.

4. Six more kids have died this season from #flu, bringing the season total to 91. That number is still lowish vis-a-via the Before Times, but getting into the low end of the range of a normal season. @CDCgov started tracking flu peds deaths after a bad year in 2003-04....

5. The first few years probably reflect a system getting started i.e. artificially low. 2009 was the H1N1 pandemic — lots of pediatric deaths. 2011-12 was a very mild season. Most years pre-Covid pediatric #flu deaths ranged between 100 & 200.

6. #Flu activity in long-term care facilities has really declined. Always a welcome development.
The whole Fluview report is here: cdc.gov/flu/weekly/

7. We still don't know how well the #flu vaccine worked this year. The strains it targets are well matched to circulating strains but that doesn't necessarily equate to terrific protection, especially with H3 viruses. @CDCgov says it will have effectiveness data in February.