I generally try not to let Twitter beefs contaminate the blog, but at least a few people last night denounced me as an idiot on the subject of airborne aerosol transmission of COVID-19. This seems to have turned into something of a truther jihad, so it's worth running down the history of this.
The whole thing started with a suggestion that perhaps Chinese virologists knew from the start that COVID-19 was transmitted via airborne aerosols while Western scientists insisted it was spread by droplets that were too big to stay suspended in the air for long. One explanation for this disagreement is that the Chinese had learned a lesson from the SARS epidemic of 2003.
But this isn't really so. Here are the basics:
- For reasons outlined a few months ago in Megan Molteni's excellent account in Wired, the epidemiological community has for years believed that aerosol transmission is only likely for particles less than 5 microns in diameter, and since most viruses are enveloped in packages larger than that they can spread only a few feet before falling to the ground. This mistaken belief was caused by a misreading of one particular study followed by inconclusive research over the next few decades. By the 1980s the tide was turning slightly on this, but scientists mostly still believed that aerosol transmission was unlikely with large particles.
- When SARS hit in 2003, epidemiologists in China believed it was mostly spread by droplets, not airborne aerosols. There was one large outbreak in an apartment complex that seemed to implicate airborne transmission, but eventually, after practically tearing the apartment complex apart, scientists concluded that the culprit was droplets spreading through a faulty sewage system. However, other studies disagreed, suggesting that airborne transmission of SARS may have played a modest role in certain kinds of settings.
- Fast forward to late 2019. The initial reporting from Chinese scientists once again suggested droplet transmission, though with some possibility of aerosol transmission. Generally speaking, there was no difference between Chinese and Western scientists on this, and Chinese treatment of COVID-19 outbreaks didn't focus on airborne transmission.
- Over the next few months, evidence for aerosol transmission began to grow. Partly this was due to new studies. Partly it was due to new evidence showing that COVID particles were not always larger than 5 microns. And partly it was due to the intervention of the physics community, which wasn't blinded by the old 5 micron standard and knew that aerosol transmission was perfectly plausible for particles considerably larger than 5 microns. By late summer of 2020, it was pretty well agreed that airborne aerosol transmission was one of the ways COVID-19 spread.
You can decide for yourself how badly this speaks of the epidemiological community. On the one hand, they obviously misjudged the role of aerosol transmission of COVID-19. On the other hand, this was a matter of considerable research in their area of specialty, and that's not something you abandon instantly based on one or two early studies.
Unfortunately, as I mentioned earlier, this subject has become something of a jihad among certain people, who are convinced that there was overwhelming evidence of airborne transmission within weeks of the first case, and anyone who denied it was simply stupid. I don't think there's any way of talking them out of this belief, but it really doesn't fit the facts. Epidemiologists clearly made a mistake here, and some of it was indeed based on stubbornness. But it was also based on a laudable desire not to overturn decades of belief overnight until the evidence was clear. There are not really any big villains here.
UPDATE: I mixed up microns and nanometers in the original post. Sorry about that. It's fixed now, along with some more precise language about exactly what it is we're measuring.
speaking of COVID
herd Immunity? At what level? Hey some people have natural immunity - good for them. They represents a small portion of the pool so to speak
Here's an intersting thought regarding Sturgis motorcycle rally - from teh Dean of Public health from brown University
https://www.washingtonpost.com/outlook/2021/09/07/sturgis-covid-delta-variant/
The annual Sturgis motorcycle rally in South Dakota is America’s largest bike rally, a 10-day blowout, with attendance this year exceeding 250,000. It was also a serious pandemic stress test. By bringing together hundreds of thousands of people, Sturgis helps answer a simple yet critically important question: Are we at a point in the pandemic where we can safely stage big-crowd events?
If there were a place where this could have happened, it should have been Sturgis. The best data suggests that at least 75 percent of the entire South Dakota population has some degree of immunity against the virus: About half of South Dakotans have immunity because they’ve been infected by covid-19, and about half of the population has been vaccinated — some of whom have already had covid-19 when they got their shot, so there is some overlap between these two groups. South Dakota, despite its middling vaccination rates, probably has among the highest levels of population immunity in the nation, driven largely by horrifying winter outbreaks.
That’s what makes Sturgis an important test. If it had gone off without big spikes in covid cases, it would have provided strong evidence that this level of population immunity — around 75 percent — would allow us to get back to the way we did things in 2019. But unfortunately, that’s not what happened. In the weeks since the rally began in early August, infection numbers have shot up more than 600 percent in South Dakota. We can expect to see big increases in other states, too, since bikers returned home from the event. Last year, after Sturgis, we saw massive outbreaks across the Dakotas, Wyoming, Indiana, even Nevada. Much of the region was aflame because of Sturgis, probably causing thousands of deaths.
{snip}
75% may or may not be an accurate assessment of immunity for SD residents. If Anything, given the political climate there I would guess that more people had it than even this guy estimates
Yet cases rose 600%. Now, SD is not an old state at 37.4 years of age average. The U.S. average age is 38.2
A 600% increase shows MORE than young people getting it. I think it's showing a far higher break through rate than we anticipated. I read an artlicle over the weekend that indicated break through cases with Delta were in the 1 in 5000 range which is very high compared to previous waves
Will Delta remain the dominant strain? Most medical people believe there are more coming - Mu, South AFrican variants BOTH evade immunity protections of the vaccinated, and those exhibited by people who have had CV in the past.
The unfortunate aspect of this is that the group highest at risk here in the U.S. is young people and they are back in school
Already outbreaks are being reported in middle and high schools in NC. They are mimicking the reporting of the initial outbreaks in the UNC system in round one.
This is far from over and with variants on the way showing evasion of the protections anti bodies give us? ALong with vaccine pressure overload, and covid exhaustion already? This will NOT be a good thing
The Dallas morning Star is reporting that over 2400 cases of Mu have been detected in 49 states across the country (sorry its behind a paywall)
The REAL issue is that they have tested LESS than 0.01% of CV cases to see if they are sequenced like Mu
Cases of he Mu variant are still rising in South America with 39% of those COVID cases in Columbia being Mu, which is widely reported as being able to evade immunities. And they are sequencing a very small % of overall covid cases
The "Health Ministry" in Israel is already talking about a 4th shot being a possibility - they have already administered 3 million 3rd shots. Thank God their population is more homogeneous that ours is.
We are running into resistance for the first shot
Now we're talking boosters and possibly a 4th shot?
On top of medical people predicting a very VERY bad flu season and advising that everyone get shots for that too?\
I need to invest in syringe manufacturers
Yep - now Florida:
https://www.newsweek.com/mu-covid-variant-outbreak-florida-hundreds-detected-cases-1627068
{snip}
Although Florida is finally starting to see a decrease in the number of new COVID-19 cases, there have been hundreds of cases detected of the Mu variant, which is more transmissible and potentially more resistant to vaccines than other strains.
Florida is getting over its worst wave of the pandemic, where as many as 27,779 new COVID-19 cases were recorded in the Sunshine State in one day. On September 6 it recorded 10,162 new cases. Some 305 of its active cases are the Mu variant, according to data from the Outbreak.info website.
However, the Delta variant remains by far the dominant strain and Mu only accounts for 0.2 percent of the total cases in the U.S
{snip}
Its spreading and evading the protections so in a sense, MU may have a totally virgin population to deal with
But every other story says its more transmissible which for now I just don't see