How do we know a pandemic's over?

[dann]

As of May 14, 2024, we estimate that COVID-19 infections are growing or likely growing in 13 states and territories, declining or likely declining in 12 states and territories, and are stable or uncertain in 22 states and territories.
Current Epidemic Growth Status (Based on Rt) for States and Territories (CDC Center for Forecasting and Outbreak Analytics, "as of May 14", 2024)

See map in link.
The only "Growing" state is Florida. The "Likely Growing" states are all the pacific coastal states + Nevada, Arizona, Texas, Minnesota, Georgia, D.C. and New Jersey.

 

[dann]

Summer FLiRT

California COVID Update:
Hospitalizations increasing,
Test positivity increasing,
Wastewater levels increasing.
Early signs of rising COVID in California as new FLiRT subvariants dominate https://msn.com/en-us/health/other/...ariants-dominate/ar-BB1n1OaP?ocid=socialshare
Yaneer Bar-Yam (X, May 25, 2024)

Thanks for posting! Confusing article blends a warning with the usual minimizing. New variant is mild but hospitalizations up and that has a high mortality, but not for you, unless you are over 65, etc etc
Dana Ludwig (X, May 26, 2024)

Yes, again MSM normalizing/minimizing Covid & LC, telling older ppl to get vaxxed, ZERO mention of ventilation/filtration of indoor air to reduce transmission. Do we need more garbage statements like "masks are much less common" & some hospitalized ppl are "very, very sick"?
Marcia Cohen Zakai (X, May 26, 2024)

In case anybody still thinks COVID-19 is (winter) seasonal:

California may be headed to an earlier-than-normal start to the summer COVID-19 season, with coronavirus concentrations in sewage rising in some areas along with the statewide positive-test rate.
The trend comes as the latest family of coronavirus subvariants, collectively named FLiRT, have made significant gains nationally.
(...)
Instead of California seeing reduced circulation of COVID-19, as occurred earlier this spring, state health official said that they estimate the spread is now either stable or slowly increasing.
(...)
Over the seven-day period that ended Monday, about 3.8% of COVID-19 tests came back positive; in late April, that share was 1.9%. (Last summer's peak test-positive rate was 12.8%, at the end of August.)
Early signs of rising COVID in California as new FLiRT subvariants dominate (LA Times/MSN, May 25, 2024)

In Denmark, the media doesn't bother showing us the local numbers (KP.2 and KP.1.1 are currently found in "about 25-30% of positive COVID-19 tests"). We just get the 'nothing-to-worry-about' "good news" as has been the custom since the post-vax winter of 2021-22 when the C19 death toll tripled in four months:

»Den gode nyhed er, at KP.2 ikke ser ud til at forårsage mere alvorlig sygdom. Faktisk er hospitalsindlæggelser i forbindelse med covid-19 på et rekordlavt niveau,« siger CNNs sundhedsekspert Leana Wen, som er akutlæge og klinisk lektor ved George Washington-universitetet.
»Og der er ingen grund til at tro, at eksisterende vacciner og behandlinger vil holde op med at virke mod den,« tilføjer hun.
(...)
»Vi er opmærksomme på dem (KP.2 og KP.1.1, red.) herhjemme, og vi ser ingen grund til den store bekymring. Der er tale om en helt naturlig udvikling af virus, og jeg ser ikke noget her, der har potentiale til at give et stort udbrud eller peak i smitten,« siger seniorforsker ved Statens Serum Institut Morten Rasmussen til Berlingske.
Ny coronavariant på fremmarch (BT, May 24, 2024)

“The good news is that KP.2 does not seem to cause more serious illness. In fact, hospital admissions in connection with Covid-19 are at a record-low level, "says CNN's health expert Leana Wen, an emergency physician and clinical lecturer at George Washington University.
"And there is no reason to believe that existing vaccines and treatments will stop working against it," she adds.
(...)
“We are aware of them (KP.2 and KP.1.1, ed.) in Denmark, and we see no reason for the great concern. This is a completely natural development of viruses, and I do not see anything here that has the potential to cause a big outbreak or peak of the infection,” says senior researcher at the State Serum Institute, Morten Rasmussen, to Berlingske.

It is completely natural, not more serious and not a big outbreak, well then ...

 

[alfaniner]

How do we know a pandemic's over?

When it reads as "ɔıɯǝpuɐd".

 

[Roger Ramjets]

For those who think it's 'over'.

Covid-19: NZ experiencing highest peak in 18 months

New Zealand is experiencing its highest peak in Covid-19 cases since December 2022, professor Michael Baker says.

Last week, the ministry reported 6146 new cases of the virus and 19 further deaths.

That was a substantial increase on the number of cases reported the previous week - which stood at 3922.

The data came from wastewater testing, Baker said, but hospitalisations were also up.

Unfortunately the RNZ Covid page is very tardy in updating its data now. Hospitalization numbers stop at the 5th of May, and wastewater at the 12th of May (2 weeks ago). I hate to think what it looks like now!

BTW,
Stricter mask use could reduce the spread of respiratory infections

Stricter use of masks could seriously reduce the spread of respiratory infections like the flu, researchers from the University of Otago say...

"The findings of this rigorous review and reanalysis put an end to that uncertainty. We now have a clear pathway to action, including reducing the number of respiratory infections in winter 2024."

Typical cloth face coverings were proven to have a positive impact, but the most effective were N95 and FFP2 respirators.

 

[Roger Ramjets]

I posted this in the science thread yesterday.

Since the start of omicron, we've [NZ] had an official 11% of the population infected, and I'm going to err way on the side of caution and say the true numbers are 20%, or 1M cases. (I believe it's more like 40%, using absence numbers at schools and workplaces)

Of that million infections, we've never had over 1000 in hospital, with numbers dropping right now, and maximum 40 in ICU. Deaths are listed at 192, but that is all deaths where covid has been present within 28 days of death. The number confirmed to be as a result of covid is a whopping 43.

It's now abundantly clear that post-vaccination omicron is a very minor issue. The people dying have almost exclusively been very frail people, or as my Aussie mate says, people whose toe tags had already been printed. 'Flu deaths here are ~500 a year, and omicron's going to be much lower than that.

Are you sure about that?

Deaths attributable to Covid (not 'within 28 days'):-
2022 (full year): 2699
2023 (full year): 1007
2024 to May 12: 262

(data from here)

More than half way there in 5 months, and winter starts next month.

 

[dann]

Of course, NZ managed to lower the number of the C19 death toll by coming up with another way of counting C19 deaths. It made the graph a little less steep after July 2022.
In Singapore, the combination of face masks and extensive booster vaccinations seems to have worked.
Cumulative confirmed COVID-19 deaths
It's a pity that Singapore seems to have stopped reported since the beginning of 2024.

 

[The Atheist]

For those who think it's 'over'.

The pandemic is over, the disease never will be. Like 'flu and RSV, it's going to make people sick.

Hospitalization numbers stop at the 5th of May, and wastewater at the 12th of May (2 weeks ago). I hate to think what it looks like now!

Why? Covid has put a whopping 282 people in hospital right now, zero of whom are in ICU.

That is truly disastrous, it must be time to panic!

Are you sure about that?

Meh, I was a year or two out - the 'flu and covid deaths look pretty similar this year and covid will reduce to fewer than influenza in the next year or so.

Also, I keep repeating that the few people dying of covid were already near death. Paxlovid and herd immunity is unquestionably having an effect on the disease's lethality among ordinary people.

How many people wearing masks where you are? I can assure you they're virtually invisible in Auckland outside of the same Chinese who wore them before covid.

Even the staff in pharmacies and doctors' surgeries aren't wearing them, and I bet hospital staff aren't either.

Quite rightly, nobody cares. You and Dann are two lone voices farting against thunder.

 

[The Atheist]

Of course, NZ managed to lower the number of the C19 death toll by coming up with another way of counting C19 deaths.

More nonsense.

We stopped counting people with covid who didn't die from it. We were literally counting people who died from heart attacks if they tested positive for covid within 28 days of death.

The totals now reflect reality.

 

[dann]

Minimizers Gonna Minimize - They just can't stop spreading disinformation

The NZ totals don't 'reflect reality' at all. It is so bloody stupid that only a health-care system run by rabid right-wingers could have come up with this kind of (un)reality reflection:
"People who died from heart attacks if they tested positive for covid within 28 days of death" should be counted as C19 deaths. People who die from heart attacks within 28 months of testing positive should be counted as C19 deaths, too!

This one starts with a case story. It's always a good way to catch attention:

Almost three weeks before Covid-19 was reported to be spreading in the US, Patricia Cabello Dowd dropped dead in the kitchen of her San Jose, California, home. A previously healthy 57-year-old, Dowd had complained of body aches and flu-like symptoms days earlier, but nothing could explain why she died so suddenly.
Lab results 10 weeks later revealed Dowd, a manager at a Silicon Valley semiconductor firm, was one of the first US Covid fatalities. Inflammation of the heart muscle led to a finger-sized rupture which caused lethal hemorrhage, an autopsy report showed.
A Spike in Heart Disease Deaths Since Covid Is Puzzling Scientists (Bloomberg, Feb 27, 2024)

But there's really no reason to be puzzled:

The risk of Type 2 diabetes after COVID-19 exposure for unvaccinated patients was 2.7%, with 74% occurring after COVID-19 infection versus 26% happening prior to COVID-19 exposure.
The risk of Type 2 diabetes after COVID-19 exposure for vaccinated patients was 1.0%, with 51% occurring after COVID-19 infection versus 49% happening prior to COVID-19 exposure.
(...)
Diabetes disrupts normal metabolism and metabolic processes, preventing the pancreas from producing enough insulin, a hormone that helps regulate blood levels of glucose and amino acids. Because diabetes can damage vital organs and blood vessels, people with diabetes are at higher risk for heart attack and stroke.
Verified: COVID-19 Infection Increases Diabetes Risk (Ceders Sinay, Feb 14, 2023)

Notice the good news, i.e. that vaccination at least lowers the risk of developing diabetes.

Patients with chronic cardiomyopathy may have persistent viral infections in their hearts, particularly with SARS-CoV-2, which targets the ACE2 receptor highly expressed in human hearts. This raises concerns about a potential global heart failure pandemic stemming from COVID-19, an SARS-CoV-2 pandemic in near future. Although faced with this healthcare caveat, there is limited research on persistent viral heart infections, and no models have been established. In this study, we created an SARS-CoV-2 persistent infection model using human iPS cell-derived cardiac microtissues (CMTs). Mild infections sustained viral presence without significant dysfunction for a month, indicating persistent infection. However, when exposed to hypoxic conditions mimicking ischemic heart diseases, cardiac function deteriorated alongside intracellular SARS-CoV-2 reactivation in cardiomyocytes and disrupted vascular network formation. This study demonstrates that SARS-CoV-2 persistently infects the heart opportunistically causing cardiac dysfunction triggered by detrimental stimuli such as ischemia, potentially predicting a post COVID-19 era heart failure pandemic.
Predicted risk of heart failure pandemic due to persistent SARS-CoV-2 infection using a three-dimensional cardiac model (Jan 19, 2024)

And it's not just diabetes: SARS-CoV-2 infection triggers pro-atherogenic inflammatory responses in human coronary vessels (Nature, Sep 28, 2023)

Very interesting graphic on X (from the US): Deaths per month in males aged 24-54 from cardiovascular or respiratory disease. COVID cases per month in males aged 20-49
COVID-19 is really the scourge that keeps on killing and maiming:

Still, “COVID is not just a flu or a cold,” Hudson said. “COVID can potentially for some people have very long-lasting impacts. ... Long COVID really makes things different.”
There is evolving evidence that the more times you get COVID, the more likely long COVID will develop, Hudson said. And “it does seem like people in their 30s and 40s are the ones who are more likely to get long COVID.”
Some patients have been permanently disabled by long COVID, but, Hudson said, “for most people, it does seem — maybe after 12 months, sometimes 18 months — all the symptoms do resolve. But that’s a long time to not feel good.”
Early signs of rising COVID in California as new FLiRT subvariants dominate (LA Times, May 25, 2024)

And as we know from what icerat has told us about his son, Long Covid isn't even just seen in adults.
A short (7:50 min.) video on X: Long Covid Kids - an ITV Meridian investigation (Mar 29, 2023)
More similar stories on YouTube: ITV News Meridian - Long Covid in children

I assume it can be considered as some kind of progress that we donn't heard the lie about road deaths anymore. Can we kill the toe-tag idiocy, too?

 

[dann]

COVID-19, Long Covid and Heart Attacks

"People who died from heart attacks if they tested positive for covid within 28 days of death" should be counted as C19 deaths. People who die from heart attacks within 28 months of testing positive should be counted as C19 deaths, too!

I meant to include this in the previous post, but I couldn't find it:

All major adverse cardiovascular and cerebrovascular events considered showed a significantly higher risk in COVID-19 individuals. Incidence calculated for each 6-month period after the diagnosis of COVID-19 in our population was the highest in the first year (1.39% and 1.45%, respectively), although it remained significantly higher than in the COVID-19-free patients throughout the 3 years.

Conclusion
The increase of cardiovascular risk associated with COVID-19 might be extended for years and not limited to the acute phase of the infection. This should promote the planning of longer follow-up for COVID-19 patients to prevent and promptly manage the potential occurrence of major adverse cardiovascular and cerebrovascular events.
Persistent increase of cardiovascular and cerebrovascular events in COVID-19 patients: a 3-year population-based analysis (Cardiovasccular Research, Volume 120, Issue 6, April 2024)

Your risk of serious cardiovascular events after an episode of COVID extends 3 (or more) years after. This is consistent with viral persistence after infection. The story of postCOVID conditions just gets worse with more research and information. Please avoid getting COVID!
Dr. Dick Zoutman (X, May 18, 2024)

 

[The Atheist]

The NZ totals don't 'reflect reality' at all.

Quite right - we should still be counting people with covid who died in car crashes within 28 days of diagnosis.

They might have had long covid and not been functioning properly, causing the crash!

I'll tell Shane Reti immediately.

Meanwhile, thanks for laying your absurdly stupid biases out so neatly:

... a health-care system run by rabid right-wingers...

Even my laughing dog can't cope with that.

While I'm no fan of Luxon et al, calling them rabid right-wingers is way beyond laughable. The main coalition partner, National, is slightly right of centre and always has been. They are a long way left of US Democrats and your description of them is an excellent highlight of your complete ignorance on the subject.

Doesn't stop you commenting though...

 

[dann]

It should indeed be considered as a cause of car crashes post-COVID-19 - and not just "within 28 days of diagnosis."
So far, I haven't seen improved driving skills mentioned as one of the C19 sequelae.

Dr. Becker explained that cognitive sequelae are among the most commonly reported symptoms, and this includes "brain fog," which patients describe as problems with concentration, word-finding, and memory. The data suggest that deficits tend to be the most pronounced in executive functioning, which would be frontostriatal in nature, Dr. Becker said, adding that attention and processing speed are also impacted.
The Neuropsychiatric Effects of Long COVID (MedCentral, May 25, 2023)

 

[marting]

Sequelae have nothing to do with when a pandemic is over.

For example, I used to play chess with another boy who had been paralyzed, a polio sequela. This was long after vaccines had stopped polio. He lived another 40+ years.

 

[The Atheist]

It should indeed be considered as a cause of car crashes post-COVID-19 - and not just "within 28 days of diagnosis."

Pure gold.

Every death since covid began becomes a covid death. Genius.

 

[GraculusTheGreenBird]

BTW,
Stricter mask use could reduce the spread of respiratory infections

That doesn't mention Covid though, just the flu. I think if it had found it was effective against Covid it would have mentioned it.

And I know from our experience here in Hong Kong with universal mandatory masking, that it made no difference at all during Omicron; we had exponential growth from 0 to 75,000+ new cases per day when the city was pretty much in lockdown and everyone wore masks all the time as a legal requirement.

Interestingly even the massively risk averse Hong Kongers are now starting to reduce mask wearing once the mandatory law was removed, its been around 30% for a year but now around 10% are wearing them on the street.

 

[dann]

SARS-CoV-2? COVID-19?
The respiratory disease which must not be named?!

"I think if it (??!) had found it was effective against Covid it would have mentioned it."
You think? Maybe you should consider that it's the journalist writing about the study, and not the study, who doesn't mention Covid:

Led by University of Oxford’s Professor Trisha Greenhalgh, researchers reviewed scientific evidence on the transmission of COVID-19 and other respiratory pathogens, reanalysed randomised controlled trials of masks, and examined more than 400 peer-reviewed studies. Their findings, published in the high-impact journal Clinical Microbiology Reviews, show masks – in particular respirators – are effective in reducing the transmission of respiratory infections. Associate Professor Kvalsvig says indoor air quality is generally poor in workplaces, transport, and other public settings in New Zealand, allowing viruses to spread easily during the winter months. Masking in these settings can help people to avoid catching infections and passing them on. Their use can also reduce COVID-19 reinfections that are driving the rise in Long Covid. Review highlights benefits of masks (University of Otago, May 23, 2024)

Why do you think the journalist didn't mention C19? As for people in Hong Kong, I have no idea why they have stopped masking up - if they actually have. But maybe it's time for them to start again.

MANILA, Philippines — The country’s airports and seaports have been placed on “heightened” alert to “thoroughly” screen foreigners or Filipinos coming from countries with reported cases of the new “Flirt” variants of COVID-19. (...) Based on news reports, Flirt variants have been detected in Singapore, Thailand, India, China, Hong Kong, Nepal, Israel, Australia, New Zealand, the United States and 14 countries in Europe, including the United Kingdom. PH airports, seaports on alert for ‘Flirt’ variant of COVID-19 virus (Philippine Daily Inquirer, May 28, 2024)

Meanwhile, the minimizers are busy minimizing.

The German government did not "admit" there was no coronavirus pandemic, contrary to social media posts that misrepresented documents from the country's disease control agency. The baseless claim, which is the latest reincarnation of a conspiracy theory that the virus was faked, appeared to originate on a website that regularly peddles misinformation. "The German government admits there was no pandemic," read a simplified Chinese post on Weibo shared on April 10, 2024. "Breaking news from Germany, the federal government has been forced to admit that the so-called 'conspiracy theorists' were right about everything during the corona pandemic." The Covid-19 pandemic sparked a wave of baseless conspiracy theories, including that the crisis was staged by a global elite in order to control the world. Germany did not 'admit' there was no Covid-19 pandemic (yahoo!news, May 23, 2024)

 

[GraculusTheGreenBird]

SARS-CoV-2? COVID-19?

"I think if it (??!) had found it was effective against Covid it would have mentioned it."
You think? Maybe you should consider that it's the journalist writing about the study, and not the study, who doesn't mention Covid:

Fair enough. Your quote says it "can also reduce covid reinfections". Hardly a ringing endorsement.

As for people in Hong Kong, I have no idea why they have stopped masking up - if they actually have.

Yes, they have. I live in Hong Kong. I, unlike you, actually see people on the street every day.

I know exactly why they stopped masking up, and I told you before in this thread.

Because it was clear that IT HAD NO EFFECT ON OMICRON in Hong Kong, and had not stopped the outbreak in any way, shape or form, the outbreak that happened when zero covid rules including mandatory mask wearing were firmly in place. As shown by the graphs I showed last time, and which are still available on any site that shows covid cases by country.

Once China's situation became out of control and protests started and social instability threatened, China turned on a dime and zero covid was abandoned, and that gave Hong Kong's government the leeway to follow suit and lift its own zero covid measures, the very last of which was the compulsory mask wearing.

The day after that was lifted, maybe 70% of people were still wearing them, dropping to about 50% in that first week, and about 30% after a week or 2. That 30% stayed pretty much constant for a year, and only recently I have noticed its back down to 10%.

Most of those that do are elderly, but not all.

But maybe it's time for them to start again.

The majority won't, of course. Because going down that road entails wearing a mask in the public for the rest of their lives, which is obviously never going to happen.

 

[marting]

That doesn't mention Covid though, just the flu. I think if it had found it was effective against Covid it would have mentioned it.

The study is quite a large one and covers decades of mask research including the first years of Covid-19.

https://journals.asm.org/doi/full/10.1128/cmr.00124-23

It criticizes the Cochrane report, also with decades of studies, as considering only RCTs. However, it may well have it's own biases. Look at this:

SUMMARY AND CONCLUSION
This review was commissioned partly because of controversy around a Cochrane review which was interpreted by some people as providing definitive evidence that masks don’t work (9). Our extensive review of multiple streams of evidence from different disciplines and study designs builds on previous cross-disciplinary narrative reviews (233, 412) and aligns with the recent call from philosophers of science to shift from a “measurement framework” (which draws solely or mainly on RCTs) to an “argument framework” (which systematically synthesizes evidence from multiple designs including mechanistic and real-world evidence) (19). Using this approach, we have demonstrated a more nuanced set of conclusions......

 

[dann]

Fair enough. Your quote says it "can also reduce covid reinfections". Hardly a ringing endorsement.

You're not exactly subtle when you ignore most of what the quotation says:

Led by University of Oxford’s Professor Trisha Greenhalgh, researchers reviewed scientific evidence on the transmission of COVID-19 and other respiratory pathogens, reanalysed randomised controlled trials of masks, and examined more than 400 peer-reviewed studies.
Their findings, published in the high-impact journal Clinical Microbiology Reviews, show masks – in particular respirators – are effective in reducing the transmission of respiratory infections.
Associate Professor Kvalsvig says indoor air quality is generally poor in workplaces, transport, and other public settings in New Zealand, allowing viruses to spread easily during the winter months. Masking in these settings can help people to avoid catching infections and passing them on. Their use can also reduce COVID-19 reinfections that are driving the rise in Long Covid.
Review highlights benefits of masks (University of Otago, May 23, 2024)

So as ringing an endorsement as it could possibly be. Is the problem that you are not aware that SARS-CoV-2 is an airborne respiratory disease? The phrenetic hand-washing at the beginning of the pandemic confused some people.

Yes, they have. I live in Hong Kong. I, unlike you, actually see people on the street every day.

I know exactly why they stopped masking up, and I told you before in this thread. Because it was clear that IT HAD NO EFFECT ON OMICRON in Hong Kong, and had not stopped the outbreak in any way, shape or form, the outbreak that happened when zero covid rules including mandatory mask wearing were firmly in place. As shown by the graphs I showed last time, and which are still available on any site that shows covid cases by country.

Once China's situation became out of control and protests started and social instability threatened, China turned on a dime and zero covid was abandoned, and that gave Hong Kong's government the leeway to follow suit and lift its own zero covid measures, the very last of which was the compulsory mask wearing.

The day after that was lifted, maybe 70% of people were still wearing them, dropping to about 50% in that first week, and about 30% after a week or 2. That 30% stayed pretty much constant for a year, and only recently I have noticed its back down to 10%.

Most of those that do are elderly, but not all.

You just happen to "know exactly (!) why they stopped masking up": "Because it was clear that IT HAD NO EFFECT ON OMICRON in Hong Kong"
So tell us how exactly you know that exactly: What exactly made it clear that masking up "HAD NO EFFECT ON OMICRON in Hong Kong""?
Are you referring to studies of the spread of Omicron in Hong Kong? Or is it based on people's attitude, which seems to be your main argument?
And why do the elderly continue to mask up when it is supposed to be so "clear that IT HAD NO EFFECT ON OMICRON in Hong Kong"?

I happen to live in a country where nobody at all masks up indoors in public places - not even when 140 people a day were hospitalized with C19 in mid-December '24. The only reason is that people expect the authorities to tell them to mask up when it's expedient, which they have stopped doing.

The majority won't, of course. Because going down that road entails wearing a mask in the public for the rest of their lives, which is obviously never going to happen.

And why on Earth would it entail "wearing a mask in the public for the rest of their lives"? That is the kind of hyperbole that makes it obvious why minimizers can't be taken seriously. Lockdowns and restrictions are always draconic and year-long when they tell their scary stories. In my country, they were short and not at all draconic. If you are implying that the pandemic may last "for the rest of their lives," however, you may be on to something. I don't feel like guessing how long it will last, but I'll continue to mask up indoors in public places whenever there's a new surge of Covid - as there may or may not be this summer due to the new KP.1.1, KP.2 and KP.3 Omicron subvariants..

But read up on the face mask (and respirator) studies. You may learn something that your own private observational study didn't reveal.

 

[dann]

The study is quite a large one and covers decades of mask research including the first years of Covid-19.

https://journals.asm.org/doi/full/10.1128/cmr.00124-23

It criticizes the Cochrane report, also with decades of studies, as considering only RCTs. However, it may well have it's own biases. Look at this:

"evidence from multiple designs including mechanistic and real-world evidence" means the kind of evidence that you can get from studying how the filtration of the air (i.e. mechanistic) limits the number of viable virus particles inhaled and/or the number of viable virus particles in the air when infected test subjects wear masks. It is in many ways similar to studies showing how air filtration limits the number of reproducible virus particles per m3 air in hospitals.

It is not the same as an RCT study, but many RCT studies of masking were of very limited value for a number of reasons. The one in Denmark, for instance, seemed to show a small degree of protection from wearing face masks, but it was carried out at a point in time when the majority of people had stopped masking up because the rate of infection at the time was very low.

Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection.
Limitation:: Inconclusive results, missing data, variable adherence, patient-reported findings on home tests, no blinding, and no assessment of whether masks could decrease disease transmission from mask wearers to others.
Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers : A Randomized Controlled Trial (PubMed, Nov 18, 2020)

And yet, anti-maskers claimed that the Danish study showed that masks didn't work. It showed no such thing.

Swedish schools would have been the ideal place carry out an RCT of masks. In fact, the people behind the Bangladesh study offered it to Anders Tegnell and his cronies, but they turned it down - for no apparent reason. (It is well-known that Tegnell is an anti-masker, but I don't think that a reason for turning it down was ever presented.)