Thread by @kerpen, Friday Fluday Thread: Influenza-Like Illness Data for MMWR Week 17, ending May [...]

Friday Fluday Thread: Influenza-Like Illness Data for MMWR Week 17, ending May 1, 2021

United States Influenza testing, MMWR week 17.

CDC flu view. https://cdc.gov/flu/weekly/index.htm

2016 to 2019 4-year average: 1,243 cases; 8.50% positive
2020: 48; 0.41%
2021: 15; 0.05%

https://docs.google.com/spreadsheets/d/1JXUW_6CF4e04iAWyC_MU23SY6scEYUo4GKEXmQUhHbo/edit?usp=sharing

United States Influenza testing, season to date (31 weeks, MMWR 40 to 17)

Five-year average: 206,764 cases; 18.45% positive

This year: 2,059; 0.14%

Season-to-date U. S. flu hospitalizations down 98.9% from last year.

Flu hospitalizations (31 weeks) in FluSurv-NET catchment is 226 (+2 from last week). Through week 17 last year (30 weeks) it was 20,038 (+106).

Rate last year: 69.0 per 100K
This year: 0.8 per 100K

Influenza-Like Illness (ILI) continues to be historically low and flat again this week.

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

Lots of rhinoviruses (just ticked down, potential peak forming?) and some adenoviruses all year.

Flu A, B micro-wave already over. RSV, and PIV back at low levels.

HCoVs back and rising.

https://syndromictrends.com/

Out-of-season HCoV wave continues.

HCoV NL-63 has peaked. HCoV-OC43 still rising sharply. HCoV-229E rising at lower levels. Last year's dominant HCoV-HKU1 still near zero.

CDC data shows the same picture. https://cdc.gov/surveillance/nrevss/coronavirus/natl-trends.html

CDC HCoVs by region. https://www.cdc.gov/surveillance/nrevss/coronavirus/region.html

Florida. Schools open all year. No lockdowns since September. Rhinoviruses and adenoviruses all year.

Flu finally reappeared in one region.

Recent ILI rise -- driven by rhino, RSV, adeno, and especially PIV -- leveling off?

RSV ED visits rise again.

http://floridahealth.gov/diseases-and-conditions/influenza/_documents/2021-w17-flu-review.pdf

Sweden week 17. No masks, no lockdowns, no school closures under age 16 -- and a full year with no Flu A, Flu B, or RSV; RSV level after reappearing finally three weeks ago. HCoVs resume rise.

https://karolinska.se/globalassets/global/2-funktioner/funktion-kul/klinisk-mikrobiologi/epidemiologi/rapport-influensa--och-rs-virus-och-andra-luftvagspatogener.pdf

Germany week 17. Rhinoviruses fall. As last week, slight decrease for HCoVs and increase for SARS-CoV2, so that inverse relationship holds.
https://influenza.rki.de/Wochenberichte/2020_2021/2021-17.pdf

Brazil. Very lax control measures, and a president who urges people to disregard them. A completely skipped flu season.
https://apps.who.int/flumart/Default?ReportNo=7

The global flu chart from WHO.
https://apps.who.int/flumart/Default?ReportNo=10

The exceptions.
https://apps.who.int/flumart/Default?ReportNo=4&ITZRegion=

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.

https://apps.who.int/iris/bitstream/handle/10665/329439/WHO-WHE-IHM-GIP-2019.1-eng.pdf?ua=1

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.
https://apps.who.int/flumart/Default?ReportNo=7

The idea mitigations worked but unmitigated SARS-CoV2 just has a higher R (popular now among the same crowd that still 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.

Rhinoviruses 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, then returned 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. https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30114-2/fulltext

Interference between rhinovirus and influenza A virus: a clinical data analysis and experimental...

These findings show that one respiratory virus can block infection with another through stimulation of antiviral defences in the airway mucosa, supporting the idea that interference from rhinovirus...

https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30114-2/fulltext

This great short article from @m_soond explains the viral interference theory of this respiratory season: https://medium.com/illumination-curated/the-unexpected-case-of-the-disappearing-flu-64fd1fa5e909

The Unexpected Case of the Disappearing Flu

Some endemic respiratory viruses on hiatus during the 2020–21 season

https://medium.com/illumination-curated/the-unexpected-case-of-the-disappearing-flu-64fd1fa5e909

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." https://www.forbes.com/sites/brucejapsen/2021/03/24/rite-aid-soft-cough-cold-and-flu-season-triggers-bigger-annual-loss-than-expected/?sh=59c37d60269f

Rite Aid: Weak Cold And Flu Season Triggers 2021 Loss

Rite Aid warned of a soft cold and flu season that’s going to hit the company’s bottom line worse than expected for its fiscal 2021.

https://www.forbes.com/sites/brucejapsen/2021/03/24/rite-aid-soft-cough-cold-and-flu-season-triggers-bigger-annual-loss-than-expected/?sh=59c37d60269f

Pediatric internships and residencies have to be extended or supplemented because they just didn't have enough patients to gain the normal amount of clinical experience. https://www.aappublications.org/news/2021/03/17/match-day-commentary-031721

Commentary: Residency programs must address new interns’ divergent skills, experience

https://www.aappublications.org/news/2021/03/17/match-day-commentary-031721

CDC still reports just one pediatric flu death this season.

The numbers in chart in previous tweet are lab-confirmed only, but flu testing is very limited (see totals at top of thread) so CDC also publishes best estimates of total pediatric flu deaths.
https://cdc.gov/flu/about/burden/index.html

COVID testing is much, much more abundant that flu testing and the definition of deaths typically used (any cause of death within 30-60 days of a positive test result) tends to overcount.

The CDC examined 182 pediatric death certificates that included COVID in calendar year 2020 and found that 64 of them (35%) had a cause of death with no plausible connection to COVID. https://twitter.com/andrewbostom/status/1379861668847566849/

https://twitter.com/andrewbostom/status/1379861668847566849/

Keeping that in mind, this table compares CDC best estimates of pediatric flu deaths in recent years with the first two seasons of pediatric COVID deaths.

(Note that everywhere in the world where COVID was epidemic, it circulated *instead of*, not in addition to, influenza.)

We are now near the end of the *safest* respiratory season for children ever recorded. (Even where schools never closed and nobody masked.)

Yet many places locked children out of school, and some places are still doing so. Many more kids are masked. It's a disgrace.

Absurd lie from Fauci.

What data shows masks stopped flu? The data showing zero flu in places with no masking? All the RCTs?

@chucktodd just lets that nonsense go? Wouldn't a competent interviewer respond: "Really? Then why did Sweden and Brazil completely skip flu season too?"