Thread by @kylamb8

Today the CDC acknowledged what has been known for several weeks: the flu has largely disappeared this flu season in the southern hemisphere. The CDC is spinning this as being the result of mitigation (masks, lockdowns, etc.). This thread will show that to be false.

-1-

First off, WHO has NEVER found lockdowns/mitigation to stop the flu. Here is their guidance from 2019 saying isolation/quarantine simply doesn't work

-2-

Let's be more blunt, a working group by WHO found in 2006 that there has never been any evidence of quarantine/isolation strategies stopping the spread of the flu

-3-

So what's the deal? I believe it's the virus itself that's impeding the flu. But to show that, I need to eliminate mitigation as a factor. More on that on a moment. But I have been calling this: they're banking on a light flu season to take credit.

https://twitter.com/kylamb8/status/1304638182575738880?s=20

-4-

The flu has been seen at historically low levels in the Southern hemisphere. Under 2% positive rate, in fact. Most years, WHO reports southern temperate regions to be between 10-30%. Not a single one has been at 10% this year.

-5-

So if it's not mitigation, why did the flu disappear then. As I said, I think it's the virus itself causing it to disappear. To illustrate this, let's use a normal flu season here in the U.S.

-6-

First, here are the last three years for confirmed Flu hospitalizations in the U.S. for calendar weeks 1-17. These are on a per 100,000 basis. You can see a steady, reliable downward trend in the yellow weeks 10-17.

-7-

Now let's look at Flu surveillance for cases and tests in U.S. clinical labs by the same weeks for the same three years. The highlighted columns are percent positive tests. Again, we see positive testing fall slowly and consistently.

-8-

Now that we have established our baseline for flu trends, let's go back to hospitalizations and add in this flu season (2019-20). Strangely (or not), flu hospitalizations fell off a cliff starting after week 10 (week ending March 7).

-9-

You might ask, well is it because of lockdowns? They didn't start until weeks 12-14 in most areas and wouldn't have changed the numbers that quickly. Was it no more flu testing? No. See what happens to the percent positive testing in the same timeframe.

-10-

Almost by magic, while testing did not really decrease much until at the very end, the percent of tests that were positive just completely vanished. Gone. Flu was nowhere to be found.

-11-

To me, since flu disappeared here in the U.S. when Covid-19 arrived AND disappeared in the southern hemisphere where Covid was already lurking when flu season began, this demonstrates circulation of Covid-19 is causing disruption in flu spread; NOT mitigation causing this.

-end-

Addendum #1: Folks are still trying to argue lockdowns helped and this is a terrible argument. I have receipts.

Only 3 stay at home orders took effect at the very end of MMWR 12 (March 21); AK, CA & CO. Rest were 13/14

Lab results are when REPORTED to CDC (not collection)

So most results reported week 13 were likely from week 12 or possibly before. It would take an additional few weeks for mitigation to have any impact. At minimum, if lockdowns had ANY impact it wouldn't show until ~14 or 15. By then, its' very clear from the data flu was done.

Let's spell this out so there isn't confusion:

Literally, the nosedive cannot be reasonably explained by mitigation. We know masks were not a factor and the timeline here explains why lockdowns didn't do it.