Thread by @kerpen

Friday Fluday Thread, MMWR Week 12

United States Influenza testing, MMWR week 12.

CDC flu view. cdc.gov/flu/weekly/ind…

Five-year average: 5,130 cases; 17.67% positive

Last year: 3,800; 7.08%

This year: 21; 0.06%

docs.google.com/spreadsheets/d…

United States Influenza testing, season to date (26 weeks, MMWR 40 to 12)

Five-year average: 185,193 cases; 18.87% positive

Last year: 284,840; 22.13%

This year: 1,893; 0.16%

Season-to-date U. S. flu hospitalizations down 98.9% from last year, which was a typical year.

Flu hospitalizations total (26 weeks) in FluSurv-NET catchment is 213. Through week 12 last year (25 weeks) it was 19,543.

Rate last year: 67.3 per 100K
This year: 0.7 per 100K

Influenza-Like Illness (ILI) continues to track well lower than the mild 2015-16 and 2011-12 seasons.

Still just one U.S. pediatric flu death this season. (There are 127reported pediatric deaths with COVID this season.)

Latest U.S. non-SARS-CoV2 syndromic data from BioFire.

Lots of rhinoviruses and some adenoviruses all year.

Flu A, B, RSV, and PIV are all back at low levels.

syndromictrends.com/metric/panel/r…

HCoV-OC43 and especially HCoV-NL63 continue to roar back. HCoV-229E rising now too.

CDC hasn't updated its HCoV data yet this week, but note that the drop at end of charts I shared last week was a glitch -- they had a row of zeroes in the source table.
cdc.gov/surveillance/n…

Florida. Schools open all year. No lockdowns since September. Rhinoviruses and some adenoviruses but nearly no flu; PIV has reappeared. RSV now above baseline and still rising.
floridahealth.gov/diseases-and-c…

Sweden week 12. No masks, no lockdowns, no school closures under age 16 -- and nearly a full year with no Flu A, Flu B, or RSV. HCoVs continue to rise.
karolinska.se/globalassets/g…

Germany: Still no influenza. HCoVs up (despite strict lockdowns); SARS-CoV2 down.

https://twitter.com/FrankfurtZack/status/1375369519233896449

Brazil. Very lax control measures, and a president who urges people to disregard them. A completely skipped flu season. apps.who.int/flumart/Defaul…

The global flu chart from WHO.
apps.who.int/flumart/Defaul…

But flu did not disappear everywhere.
apps.who.int/flumart/Defaul…

It wasn't masks, which were never used in many countries where flu disappeared and have also been shown to be ineffective for stopping influenza in many, many studies.

Japan masks every year, and pushed masks hard in 2019 with no apparent effect. But in 2020-21 flu disappeared with low stringency COVID intervention.
apps.who.int/flumart/Defaul…

The idea mitigations worked but unmitigated SARS-CoV2 just has a higher R (popular now among the same crowd that said twindemic! when flu had been gone for months) is way too facile.

Outside of testing ramp up, I don't think we've seen R > 2, even in places without NPIs.

Rhino bounced right back despite lower R and RSV was gone until recently with comparable R to SARS-CoV2.

HCoVs were gone until SARS-CoV2 declined but are now surging even with lockdown.

Plus, as Biden adviser Dr. Michael Osterholm points out, our mitigation just hasn't been very effective. Maybe in places like Australia and New Zealand where mitigations stopped SARS-CoV2 they also stopped other viruses. But in countries where SARS-CoV2 went wild? No.

Osterholm: "There is this viral interference"

Viral interference is a well-known (but poorly understood) phenomenon. Interference from rhinovirus is generally thought to have ended the swine flu epidemic in 2009.
thelancet.com/journals/lanmi…

This great short article from @m_soond explains the viral interference theory of this respiratory season:
medium.com/illumination-c…

Overall the season has been so mild that drug store chains took big losses.

Rite Aid CEO Heyward Donigan: "During the fourth quarter our industry was impacted by a historically soft cough, cold and flu season."

forbes.com/sites/brucejap…

Pediatric internships and residencies have to be extended because they just didn't have enough patients to gain the normal amount of clinical experience.

https://twitter.com/DrKristenW/status/1374095951170830336

But we did keep the hospitals busy -- with children in psychiatric distress.

We're seeing reports like this from all over the country. The empty pediatric wards usually used for respiratory disease have been converted to child psych overflow.

https://twitter.com/DrKristenW/status/1374911931681796098

The bottom line is many places locked kids out of school during the *safest* respiratory season (everywhere, including the places schools never closed) for children ever recorded. It's a disgrace.