How do we know a pandemic's over?

[FatherLukeduke]

How do you control for transmission outside of the place where the filter is?

Why would you need to? You take a large enough sample size of similar environments, say schools or care homes, use filtration in half and not in the others and see how it affects infection rates and sick days. You just need a large enough sample size - if people are still getting sick at the same rate with filters (whether that is because of outside infection or not) then it still tells you they are waste of time and money. Of course I'm being simplistic and actual studies will use way more sophisticated design protocols.

According to East Anglia there are 5 studies that should be coming in soonish.

It is excellent that five cluster RCTs were registered since 2020, in four different countries, to evaluate deployment of ATT to reduce respiratory infections. These trials will have evaluated both HEPA (n = 3) and GUVL (n = 2). According to registrations, two school-based trials (ISRCTN46750688; NCT05016271) were scheduled to finish data collection by late 2022; while three experiments in care home settings (NCT05084898; ACTRN12621000567820; ISRCTN63437172) will finish data collection in 2023 and 2024

Look up the studies if you want to find out about their protocols - you can even try. There are links in the paper, including methodologies being used. Contact the researchers if you're super keen.

https://www.sciencedirect.com/science/article/pii/S0091743523003602

 

[icerat]

You just need a large enough sample size

Sure, and over a long enough period - because it's not just one off infection rates that matter, it's also duration between infections.

So how big a sample size do you need to have the power to detect an effect? In my experience, nearly always bigger than the studies have.

- if people are still getting sick at the same rate with filters (whether that is because of outside infection or not) then it still tells you they are waste of time and money.

No it doesn't. I did the math on a mask study in Canada that found "no effect" and calculated that if the masks had been *100% effective* at blocking all possible transmissions, the study couldn't have found it.

Of course I'm being simplistic and actual studies will use way more sophisticated design protocols.

I think you're being a bit naïve there. Most studies really are crap.

https://www.sciencedirect.com/science/article/pii/S0091743523003602

A systematic review of crap studies just gives a summary of crap studies - for something we don't even need to waste money on crap studies on - because we can literally *see* that HEPA filters remove virions, therefore they *must* reduce risk of infection in the environment they're used.

No RCT is needed. It's physics, which is a far far higher standard of evidence.

if an RCT didn't find an effect of something we *know* is happening, it's because the effect got drowned in confounders, primarily in the case, likely the community infection rate. You didn't get infected at school, you got infected somewhere else. The conclusion *can't* be that the HEPA doesn't work, because we know they work. The conclusion should be *we need the HEPA filters in the other environments as well*.

What's also missed in these studies is actually how small of an effect we need to make a significant effect on an epidemic. If R_eff is say 1.1, just a 10% decrease in infection rate takes R_eff under 1 - an epidemic wave goes from growing to waning.

But you almost certainly won't see that in an RCT.

If an RCT of things like filtration and masking does find an effect, despite all the confounders, then it means the actual effect must be massive to poke it's head above the ocean of confounders.

 

[dann]

Ok, I finally get it.

You're jealous of successful people and want to bring them down to your level because they have more money than you.

What a sad way to live your life.

As always, The Atheist gets nothing at all.
I want everybody to be lifted up to the same level of protection from a devastating disease as billionaires are when they are protected by the #DavosStandard.
I don't remember how many times I wrote this already.
The Atheist's understanding of English is deplorable!

 

[dann]

Most studies really are crap.

I'm afraid this new Danish study is. I'm not even sure it's meant to be more than misdirection.

 

[dann]

My point was not that purifiers are a joke, but that it seems obvious that purified air will certainly not be better than fresh outdoor air for pathogen density etc.

I don't see why, or compelling evidence so far that, appropriately designed air purifiers should have next to no effect in situations where you are already are using/have no choice but to use recirculated air in your building.

Yet that meta study calls outdoor air exchange the ideal control group.

OTOH if you're saying, where the climate allows for it, instead of fancy air filters we should just get box fans and open windows, yeah, absolutely.

It does make sense to compare air purifiers with outdoor air. In RCTs of new drugs, the control group will often be a group receiving another kind of drug or treatment - in particular, when it would be unethical to deprive the control group of treatment, i.e. give them a sugar pill.
A recent Danish test of a new COVID-19 vaccine (now abandoned) compared the new vaccine with already existing vaccines (Comirnaty). It would be unethical to leave the control group unprotected, i.e. give them saline injections instead of vaccinating them.
See the Science-Based Medicine article on the previous page.

 

[The Atheist]

My point was not that purifiers are a joke, but that it seems obvious that purified air will certainly not be better than fresh outdoor air for pathogen density etc.

The gold standard must be air from outside that has been filtered. That's what we use for data centres, so it seems to me that if it's good enough for inanimate objects, it's what should aspire to for children.

Only problem is, it's not cheap.

I don't see why, or compelling evidence so far that, appropriately designed air purifiers should have next to no effect in situations where you are already are using/have no choice but to use recirculated air in your building.

Better than nothing isn't the aspiration of the "Davos standard at any cost" brigade, who I notice are rapidly backing away from that, because air purifiers weren't the only means of clean air provided at Davos.

 

[Horhang]

As always, The Atheist gets nothing at all.
I want everybody to be lifted up to the same level of protection from a devastating disease as billionaires are when they are protected by the #DavosStandard.
I don't remember how many times I wrote this already.
The Atheist's understanding of English is deplorable!

Ok maybe I have missed this but at this point I have to ask. OK dann the pandemic is not over, so what do we do and when do we stop taking whatever precautions you think we should still be taking? When will the pandemic ever be over given that the virus now has multiple hosts and we can not eradicate it? How is that not in fact an endemic disease? Be specific please.

 

[dann]

Some of your questions are plain stupid. "When will the pandemic ever be over?", for instance.
I finished answering how the current situation is still a pandemic in post 398.

 

[jt512]

Some of your questions are plain stupid. "When will the pandemic ever be over?", for instance.
I finished answering how the current situation is still a pandemic in post 398.

Yeah, and, as I have explained, you have been wrong ever since post 398.

Answer the question: How will you know when the pandemic is over? Or, equivalently, what does endemic Covid-19 look like to you?

 

[icerat]

Ok maybe I have missed this but at this point I have to ask. OK dann the pandemic is not over, so what do we do and when do we stop taking whatever precautions you think we should still be taking?

There's an implication here that we don't take precautions against non-pandemic diseases?

When will the pandemic ever be over given that the virus now has multiple hosts and we can not eradicate it? How is that not in fact an endemic disease? Be specific please.

Given the nature of this virus and current policies, the current pandemic will never be over. The one possibility is sterilising vaccines, but the success of the anti-vax movement makes that unlikely to.

We have aspirational goals to eradicate diseases like measles and rabies, which will likely never occur, but we should set the same goal for Covid - certainly in wealthy countries - such that cases are minimised and we deal with outbreaks rather than ongoing "endemic waves"

 

[dann]

Why don't you provide us with those quotations I've asked you for since a long time before post 398? You know, the ones that would back up your claim about those WHO representatives who allegedly supported your claim that the pandemic was no longer a pandemic?
I am sure that you would have if you had been able to find any.

 

[icerat]

Yeah, and, as I have explained, you have been wrong ever since post 398.

Answer the question: How will you know when the pandemic is over? Or, equivalently, what does endemic Covid-19 look like to you?

Certainly not when waves continue to be unpredictable in timing and magnitude. Given the rate of mutation of immune evasive variants, that's unlikely to end any time soon.

I expect that sooner or later the pandemic will "officially" end simply by redefining what these words mean.

 

[jt512]

Given the nature of this virus and current policies, the current pandemic will never be over.

This is wrong. An epidemic (or pandemic) is over, by definition, when the incidence of the disease attains a usual level. This is called the endemic level. Whether this level is high or low, is irrelevant. What matters is that it is the status quo.

As I have tried to explain, that is where we are with Covid-19 today. Almost everybody who is going to be vaccinated has been. Almost everybody who could be infected has been. Therefore, nothing in the future (save a sterilizing vaccine) is going to change the level of herd immunity that we now have. We have reached status quo. Covid-19 is endemic, or equivalently, it is no longer pandemic.

 

[dann]

The gold standard must be air from outside that has been filtered. That's what we use for data centres, so it seems to me that if it's good enough for inanimate objects, it's what should aspire to for children.

Only problem is, it's not cheap.

And to The Atheist, that's the only relevant problem: expenses!
Because you and your children are definitely not worth it.

Better than nothing isn't the aspiration of the "Davos standard at any cost" brigade, who I notice are rapidly backing away from that, because air purifiers weren't the only means of clean air provided at Davos.

I wasn't aware that there's a brigade! But since I haven't backed away from #DavosStandard, I am obviously not a member.

But read the article that The Atheist links to! It's a great!

There's an old saying, "Do as I say, not as I do." So a big question is what are political and business leaders actually doing about Covid-19 precautions for themselves right now? Plenty of them have been publicly pushing for Covid-19 precautions to be dropped. In fact, some have even claimed that the pandemic is over, as I covered for Forbes back in September 2022. Yet, the pandemic doesn't look too over at that gathering of political and business leaders at Davos, Switzerland, known as the World Economic Forum.
World Economic Forum: Here Are All the Covid-19 Precautions at Davos (Forbes, Jan 20, 2023)

The Atheist's point is obvious: Schoolchildren aren't entitled to any kind of protection. (He has even argued that children shouldn't be vaccinated against C19 because it would somehow make them miss out on all the other vaccines that children are routinely immunized with.) The only people entitled to proper protection against SARS-CoV-2 are billionaires and politicians.
And why worry about the pandemic anyway if only it can be prevented from harming business interests, right? According to The Atheist, those who listened to him "made a heap of money," and that's what it's all about, that's the kind of world he dreams of living in.
(His claim about people making money by listening to him is as imaginary as his other claims, but it's a wonderful fantasy, isn't it?! Something to be proud of, in his line of daydreaming.)

By the way, much like people at Davos, The Atheist is aware that masking up actually works! "I wear one as well."
Interesting, isn't it?! It's almost as if he actually knows that there's a pandemic going on, that it kills and maims people, and that you can protect yourself and others from it by using face masks and other PPE.

 

[icerat]

This is wrong. An epidemic (or pandemic) is over, by definition, when the incidence of the disease attains a usual level. This is called the endemic level. Whether this level is high or low, is irrelevant. What matters is that it is the status quo.

Full disclosure: Amongst other things, I'm an epidemiologist, so yeah, I know how it works. There are no clear, agreed upon definitions of these things. The closest clear definition you might get of endemic is R_eff=1, ie roughly the same number of cases, and predictable. What we're still getting with Covid is unpredictable waves.

Influenza would be a forever pandemic if it wasn't so seasonal and the waves were global.

As I have tried to explain, that is where we are with Covid-19 today. Almost everybody who is going to be vaccinated has been. Almost everybody who has gotten infected has been.

Yes, so?

Therefore, nothing in the future (save a sterilizing vaccine) is going to change the level of herd immunity that we now have. We have reached status quo. Covid-19 is endemic, or equivalently, it is no longer pandemic.

There is no such thing as herd immunity for this virus, and there won't be until we get a sterilizing vaccine. There's certainly no "status quo" in a constantly changing situation.

 

[jt512]

Why don't you provide us with those quotations I've asked you for since a long time before post 398? You know, the ones that would back up your claim about those WHO representatives who allegedly supported your claim that the pandemic was no longer a pandemic?

Dann, maybe to you, as a lay individual, the pandemic is over when some official health organization tells you it is. To me, as a professional in the field, a pandemic is over according to the definition of what what a pandemic is.

 

[jt512]

There are no clear, agreed upon definitions of these things. The closest clear definition you might get of endemic is R_eff=1.

It's late here and I will respond to your post more fully at a later time. But for now, I challenge you to cite any generally acceptred definition of "endemic" that is based on an R_eff of 1.

 

[icerat]

Dann, maybe to you, as a lay individual, the pandemic is over when some official health organization tells you it is. To me, as a professional in the field, a pandemic is over according to the definition of what what a pandemic is.

Well then, you'd know a pandemic is an epidemic of global proportions.

What's an epidemic to you?

 

[jt512]

Well then, you'd know a pandemic is an epidemic of global proportions.

What's an epidemic to you?

Basically, an abnormally high incidence of a disease.

 

[icerat]

Basically, an abnormally high incidence of a disease.

How do you define "abnormal"?