[WhompingWindows]

You haven't mentioned social behavioral change in your speculation about the decimated 2020-2021 flu season. I'd wager that has a very large part in why the flu hasn't spread: everyone is socially distanced, remote, masked, extra hygienic, and extra aware of illness.

[goatinaboat]

everyone is socially distanced, remote, masked, extra hygienic, and extra aware of illness.

Flu has been eradicated by lockdown, but lockdown must continue because COVID has not. That appears to be the policy right now.

[timr]

I didn't mention it because it's not addressed by this article, which is specifically about competitive inhibition.

That said, if you're going to claim that all of these things we have done have eliminated the flu, you should take at least a few moments to reflect on the fact that they have done ~nothing to rhinovirus.

[codeulike]

Flu has an R0 of about 1.3, Rhinovirus has an R0 of around 2.7, and Covid is estimated to have an R0 of 2.7 or higher. So it makes sense that the measures we have taken have stopped the flu but not stopped covid or rhinovirus.

Sources: https://www.qps.com/2020/10/05/covid-19-versus-the-seasonal-... https://www.sciencedirect.com/science/article/pii/S246804271... https://www.bmj.com/content/369/bmj.m1891

[timr]

You are leaning way too hard on point estimates of R0. The way people estimate R0 is noisy, and the error bars on these estimates are significant. It's fairly pointless to take any two papers and compare the values as if they're precise.

This literature review has estimates of R0 for flu running from 1.06-3.4, and rhinovirus running from 1.2-1.83:

https://www.medrxiv.org/content/10.1101/2020.02.04.20020404v...

Given the uncertainties involved, these ranges are effectively identical, with flu maybe being a bit more contagious.

[codeulike]

OK I've got a better idea:

In the particular conditions we created in 2020, the Rhinovirus was better able to spread than the Flu. Why?

Because people were on the lookout for fever (and other things like continuous cough etc). Flu causes fever, and anyone who got a fever and was sensibly-minded would self isolate at least for a few days until they got test results or until symptoms abated. Whereas Rhinovirus is much less likely to cause a fever, so people twig that they've 'just got a cold' and carry on going about their day.

Especially for schoolkids - if they've got a fever, they're kept at home. If they've just got a snotty nose then they're likely to still go to school.

So Rhiniovirus was able to fly under the radar whereas Flu wasn't.

[timr]

Could be. Covid is certainly more flu-like than rhinovirus-like. Kids were also not in school, and kids are historically a big spreader of influenza.

I generally think people look for "fancy" explanations for the trends, when simpler explanations (i.e. people weren't going to the doctor) work just as well.

[BoiledCabbage]

> That said, if you're going to claim that all of these things we have done have eliminated the flu, you should take at least a few moments to reflect on the fact that they have done ~nothing to rhinovirus.

Why do you keep saying these measures have done nothing to rhinovirus?

The link you've shared does not support that. It shows relative percentages - and you're confusing that for absolute infection counts.

Unless you also believe that 60% of the population has a stomach virus on a daily basis (data from their other chart).

[timr]

> Why do you keep saying these measures have done nothing to rhinovirus?

Because they haven't.

> The link you've shared does not support that. It shows relative percentages - and you're confusing that for absolute infection counts.

I am not confusing it. It shows you the percentage of samples they test that come up positive for rhinovirus (and other things. They test for all of the things listed, in parallel.)

Influenza A & B, RSV, and some other viruses have been virtually eliminated across their sampled population. The rate has dropped to zero. Rhinovirus has not -- the rate of detection is unchanged.

[BoiledCabbage]

Again, you're confusing percentages.

To use some simplified numbers to explain it - consider that normally 100,000 people are infected with some form of respiratory virus on a daily, basis and 20% of those are rhinoviruses, then that means there are 20,000 daily rhinovirus infections. And let's also say that strains of influenza are another 20% and 20,000/day.

Now what is happening, is in a covid world, due to masks and distancing, the number of people infected on a daily basis drops from 100,000 to 10,000. Rhinoviruses are sill 20% of that, but they are now down to 2,000. Masks and social distancing has had a drastic affect on them.

Influenza drops down to only 2% so only 200 cases daily. Masks and distancing have an even more drastic effect in influenza.

As a result, we're seeing exactly the graph you've linked.

Rhinovirus is 20% rate, but of a much smaller pie. And you're mistaking that as masks and distancing having little or no effect.

[timr]

I am not "confusing percentages". You (now) agree with me on what the data says, you just don't like how it fits in with your theory.

> Now what is happening, is in a covid world, due to masks and distancing, the number of people infected on a daily basis drops from 100,000 to 10,000. Rhinoviruses are sill 20% of that, but they are now down to 2,000....Influenza drops down to only 2% so only 200 cases daily. Masks and distancing have an even more drastic effect in influenza.

Yes, I understand your hypothesis: masks make influenza go down to almost 0, but somehow rhinovirus ends up at exactly the same percentage as it was before. In other words: masks work exceptionally well for flu, don't work at all for rhinovirus.

This is a theory. It is...implausible...but if you want to believe it explains the patterns in the data, you're certainly welcome to do so.