The Vaccine Thread

[zachateseverything]

J and I chatted about the article below. He may have summarized the convo in the other Covid thread.

What Really Happened With that Weird Yankees COVID Outbreak
By David Wallace-Wells

Last week, in very short order, eight members of the New York Yankees, all of whom were apparently “fully” vaccinated, tested positive for COVID-19, confusing and alarming many Americans — not to mention Yankee fans — who had assumed that vaccination would close the book on the pandemic, at least for the vaccinated. Michael Mina, however, was not confused or alarmed. A Harvard epidemiologist who has spent the pandemic advocating for the widespread use of home-pregnancy-style rapid antigen tests, Mina has become, over the past year, one of the most clear-eyed critics of the public-health establishment and the COVID messaging that has emerged from it.

https://nymag.com/intelligencer/2021...-outbreak.html

IIRC, Dr. Michael Mina argues that asymptomatic infections in the vaccinated (and unvaccinated) shouldn't be considered contagious. High cycle thresholds and all that. CDC seems to be following this logic as they no longer track non-hospitalized "breakthrough" cases. Question is how are mild (formerly) breakthrough cases different than any mild Covid-19 case, ie, if you're a non-vaccinated person infected by a vaccinated individual who shows mild symptoms (or none at all) will you have a better outcome than being infected by a non-vaccinated "healthy" individual?

I think you're misconstruing a couple things. This is a disease with a high likelihood of asymptomatic spread. That's why the initial outbreak was so widespread. People who don't show any symptoms we associate with being sick (cough, fever, etc) can be out in public shedding virus all over the place and infecting other people. So far it seems that most of the vaccinated individuals who have tested positive have enough virus in their system to test positive on a PCR test but not enough that they're shedding enough virus to infect others.

but if you're unvaccinated it probably doesn't matter who infects you.

[beeatnik]

I think you're misconstruing a couple things. This is a disease with a high likelihood of asymptomatic spread. That's why the initial outbreak was so widespread. People who don't show any symptoms we associate with being sick (cough, fever, etc) can be out in public shedding virus all over the place and infecting other people. So far it seems that most of the vaccinated individuals who have tested positive have enough virus in their system to test positive on a PCR test but not enough that they're shedding enough virus to infect others.

but if you're unvaccinated it probably doesn't matter who infects you.

So asymptomatic (mildest) infection in the vaccinated or unvaccinated should be tracked, correct? And the terminology can be confusing, as I read Mina's responses (in the linked article) he equates absence of symptoms in the PCR positive with severity of illness and potential for transmission.

How can we distinguish between an infection we don’t have to worry about and one that could cause sickness and be transmitted?
The simple answer is that we can look at viral loads. Now that the vaccines are being rolled out, the story is going to come out in a much more robust fashion. But it’s the same story that I’ve been telling this entire pandemic: Extraordinarily low viral loads should not, right off the bat, be considered infectious. Instead, we’ve taken the opposite approach: If you’re positive on a PCR test, you’re considered infectious, and you should isolate, no questions asked, no nuance of what that PCR result means.

But a lot of people aren’t actually infectious when they’re PCR positive — it’s just a little bit of virus replicating but not enough to necessarily transmit and certainly not enough to warrant a ten-day isolation anymore. You can test positive on a PCR machine for up to four or five weeks after you’ve stopped being infectious, which can be a period as short as just three days. Sussing this out is where antigen tests come in.

These are the rapid tests we’ve discussed before.

They will only really turn positive when you’re truly positive and infectious.

Another way to put it is that, when it comes to public-health testing, the PCR test is full of false positives. To be clear, they are real positives, biologically, meaning the primers are actually binding the correct viral RNA, there is actually SARS-CoV-2 there, but does it always necessarily mean you have to isolate? If you are no longer infectious and the PCR test is telling you you are positive and that is interpreted as needing to isolate, then I would call that a false positive from a public-health perspective.

I think the argument he makes is by the time most people get tested (or receive their results) those with mild infections are no longer infectious; although, they were infectious for those first 3-5 days. The pathogenesis shouldn't be any different for a vaccinated person. Tho the CDC's policy would imply that it is.

What proportion of positive tests are we talking about?

Around 60 to 70 percent of the time that you’re PCR positive you are post-infectious. What that means is that the vast majority of people that we detected and isolated, we isolated in error — or rather, people isolated when they probably didn’t have to. They were already done with being infectious by the time they got a swab put into their nose. That’s not to say isolation never would’ve helped, just that the period when it would have been effective might’ve been 1 or 2 or even as many as 5 weeks earlier, when they were actually contagious.

[BBB]

Good thing you got the Pfizer-BioNTech ones. I'm having my second dose of Comirnaty at the start of next month.

My buddy in Sydney had his first AZ dose a few weeks ago, but the with the Delta variant having arrived on your shores and AZ's median efficacy against the Delta variant at only about 60%, he's not exactly pleased.

Yes very lucky, but it took concerns with AZ causing blood clots and a further outbreak and lockdown for the Pfizer vaccine to be made freely available, or at least slightly more freely available (at least until stocks have run low). One wonders why the vaccines were sitting around not being used in the first instance. Still, Oz's vaccine roll out has been dismal and I suspect - latest outbreak in Sydney notwithstanding - that we won't get the bulk of the population vaccinated until much later this year when additional stocks of Pfizer hit our shores.

[j44ke]

Right, what viral load is "better".

So maybe the closed atmosphere of a plane is a bad way to test the 10% individually.

[Saab2000]

Right, what viral load is "better".

So maybe the closed atmosphere of a plane is a bad way to test the 10% individually.

The atmosphere inside an airplane is changed frequently, like every two to four minutes, and filtered with HEPA filters changed regularly. Additionally, all occupants of the cabin are required to be masked.

Just FYI. This has been discussed here on this forum, if not in this thread. Airplanes aren’t considered COVID-19 superspreaders AFAIK. Let’s deal in more facts and less hyperbole.

[jimcav]

The issue is if the atmosphere (containing someone's C-19 virus) on a plane goes through the HEPA filter before you breath it. There are few studies on this. Here is one model, assuming masked passengers, and from this analysis there is a risk, though pretty small. Definitely NOT super spreader with masks, but a 1/3900 risk on a 2-hour flight if a full plane.
https://www.medrxiv.org/content/10.1...826v4.full.pdf

[Saab2000]

Excellent. Seriously. But this data is 9 months old according to what I saw on top. Meaning it’s actually ancient in the ever-changing world of data collection.

Still, thanks much for posting. The idea that airplane air is a closed system is simply bullshit. It’s not Apollo 13 on commercial aircraft.

[j44ke]

The atmosphere inside an airplane is changed frequently, like every two to four minutes, and filtered with HEPA filters changed regularly. Additionally, all occupants of the cabin are required to be masked.

Just FYI. This has been discussed here on this forum, if not in this thread. Airplanes aren’t considered COVID-19 superspreaders AFAIK. Let’s deal in more facts and less hyperbole.

We deal in a lot of facts here Saab, but we're wondering what's up with the gentleman's colleague. By his narrative, the guy went on an airplane and then returned to infect other colleagues. Doesn't make sense to me based on what I've read to date, so just trying to sort out the narrative. I didn't call airplanes super spreaders. I said that it was a bad place to test the 10% individually - meaning one person gets sick and says it was from an airplane doesn't mean it was from an airplane. To get a good sense of the true risks, you'd have to look at a large number of people and control for their actions before and after flying.

Believe me, we've been looking at the risks associated with flying in detail. My wife is flying to Paris on Monday. Then in two weeks, she flies back to the US. So we've been discussing this with our doctor and reading the scientific literature. It isn't zero risk, but it is substantially reduced risk. Being vaccinated decreases the risk even further, but viral load chisels away at some of the decrease. For example, viral load from unvaccinated infected people is higher than viral load from vaccinated infected people, so the risk associated with sitting next to an unvaccinated person is higher than the risk associated with sitting next to a vaccinated person, even if they are both infected and you are vaccinated.

You can reduce but not eliminate risk as long as there is still community spread.

[beeatnik]

Contact tracing is so weird as is reading between the proverbial lines:

https://paxex.aero/researchers-link-...g-haul-flight/

Headline: Researchers link 59 Irish COVID cases to inbound long-haul flight

Content: A report published by members of Ireland’s Department of Public Health suggests that 59 cases of COVID-19 infection over the summer, including one ICU admission, were tied to a single long-haul flight arriving in the country over the summer. While stopping short of explicitly confirming the transmission on the plane, the report notes “the potential for in-flight/airport transmission exists in this outbreak.”

In-flight transmission is a plausible exposure for cases in Group 1 and Group 2 given seating arrangements and onset dates. One case could hypothetically have acquired the virus as a close household contact of a previous positive case, with confirmed case onset date less than two incubation periods before the flight, and symptom onset in the flight case was 48 h after the flight. In-flight transmission was the only common exposure for four other cases (Flight Groups 3 and 4) with date of onset within four days of the flight in all but the possible tertiary case. This case from Group 3 developed symptoms nine days after the flight and so may have acquired the infection in-flight or possibly after the flight through transmission within the household.

Only 17% of seats were occupied during the flight and most passengers wore masks on board. Still, 13 of the 49 passengers eventually tested positive; at least nine reported to be wearing masks throughout the flight.

They also transmitted the virus to 46 other people in Ireland. In one case a passenger transmitted it to a family member who then infected 25 of 34 other people in a shared accommodation facility.

[Saab2000]

We deal in a lot of facts here Saab, but we're wondering what's up with the gentleman's colleague. By his narrative, the guy went on an airplane and then returned to infect other colleagues. Doesn't make sense to me based on what I've read to date, so just trying to sort out the narrative. I didn't call airplanes super spreaders. I said that it was a bad place to test the 10% individually - meaning one person gets sick and says it was from an airplane doesn't mean it was from an airplane. To get a good sense of the true risks, you'd have to look at a large number of people and control for their actions before and after flying.

Believe me, we've been looking at the risks associated with flying in detail. My wife is flying to Paris on Monday. Then in two weeks, she flies back to the US. So we've been discussing this with our doctor and reading the scientific literature. It isn't zero risk, but it is substantially reduced risk. Being vaccinated decreases the risk even further, but viral load chisels away at some of the decrease. For example, viral load from unvaccinated infected people is higher than viral load from vaccinated infected people, so the risk associated with sitting next to an unvaccinated person is higher than the risk associated with sitting next to a vaccinated person, even if they are both infected and you are vaccinated.

You can reduce but not eliminate risk as long as there is still community spread.

Please then stay away from language like “closed atmosphere” because that’s simply misinformation. Airplanes aren’t closed environments. That’s my point. Do better. This isn’t a fine point. It’s a huge difference.

[beeatnik]

For example, viral load from unvaccinated infected people is higher than viral load from vaccinated infected people, so the risk associated with sitting next to an unvaccinated person is higher than the risk associated with sitting next to a vaccinated person, even if they are both infected and you are vaccinated.

Source? We're talking about two individuals who are asymptomatic or presymptomatic and won't progress to severe illness?

[j44ke]

Source? We're talking about two individuals who are asymptomatic or presymptomatic and won't progress to severe illness?

CDC is the source. I just looked at the page a few minutes ago, but not finding it now.

edit: This appears to be one of the original studies. It is from March 29, 2021 in Nature.

https://www.nature.com/articles/s41591-021-01316-7

The CDC info was less technical than this report, but check my work.

[takashi]

'is so weird' is getting so old

[beeatnik]

CDC is the source. I just looked at the page a few minutes ago, but not finding it now.

edit: This appears to be one of the original studies. It is from March 29, 2021 in Nature.

https://www.nature.com/articles/s41591-021-01316-7

The CDC info was less technical than this report, but check my work.

This is interesting stuff. That paper supports the findings from the mRNA vaccine clinical trials. As Octave posted the end point is reduction of severe illness. However, from scanning the article I don't see an apples to apples comparison for viral load (mild breakthrough infection vs mild infection). Vaccination protects most from developing serious illness but if infected a mild case is a mild case in terms of viral load, likewise for a case leading to hospitalization. Vaccination obviously means more of the former and less of the latter.

However, the effect of vaccination on viral load in COVID-19 post-vaccination infections is currently unknown.

[beeatnik]

'is so weird' is getting so old

Takashi, I like your Kind of Across the Hall Passive Aggressive Style.

[j44ke]

Please then stay away from language like “closed atmosphere” because that’s simply misinformation. Airplanes aren’t closed environments. That’s my point. Do better. This isn’t a fine point. It’s a huge difference.

The risk is reduced by the partial air exchange and filtration systems on airplanes. I will give you that.

[j44ke]

This is interesting stuff. That paper seems to support the findings from the mRNA vaccine clinical trials. As Octave posted the end point is reduction of severe illness. However, from scanning the article I don't see an apples to apples comparison for viral load. Vaccination protects most from developing serious illness but if infected a mild case is a mild case in terms of viral load, likewise for a case requiring hospitalization.

However, the effect of vaccination on viral load in COVID-19 post-vaccination infections is currently unknown.

Yeah I see that now. The CDC info was in summary, so perhaps summarized optimistically.

[jimcav]

Excellent. Seriously. But this data is 9 months old according to what I saw on top. Meaning it’s actually ancient in the ever-changing world of data collection.

Still, thanks much for posting. The idea that airplane air is a closed system is simply bullshit. It’s not Apollo 13 on commercial aircraft.

sure it is old, and that was part of my point--that there is not much actual data/study on the question. The other point is that the modeling showed there isn't no risk to air travel. I think it reasonable to think that a known, pretty contagious virus could impact someone since it can go from them to you before being adequately filtered. Always stinks to be in the wrong row next to the wrong person, just even more so now. Again, not great data out there.

From the case that started tis little segment of discussion, it would be my bet that WHERE the co-worker went, and what he did while there, was more important to getting and spreading C-19 upon his return to the home office than the actual airplane, but to show that would require robust contact tracing which probably still is not adequately in place.

[Saab2000]

sure it is old, and that was part of my point--that there is not much actual data/study on the question. The other point is that the modeling showed there isn't no risk to air travel. I think it reasonable to think that a known, pretty contagious virus could impact someone since it can go from them to you before being adequately filtered. Always stinks to be in the wrong row next to the wrong person, just even more so now. Again, not great data out there.

From the case that started tis little segment of discussion, it would be my bet that WHERE the co-worker went, and what he did while there, was more important to getting and spreading C-19 upon his return to the home office than the actual airplane, but to show that would require robust contact tracing which probably still is not adequately in place.

Flying is certainly not a no-risk activity. Everyone has to make the risk assessment and act accordingly. But it's not as bad as some folks make it out to be. I think many don't grasp that the air in an airplane changes a lot.

Anyway, in timely news, I have minor cold symptoms today and I have no idea why or how, but I masked up and went to Walgreens and got a self-administered test. Negative thankfully. I'll keep an eye on my symptoms and see what happens.

Light sniffles and a blocked ear.

[beeatnik]

From the case that started tis little segment of discussion, it would be my bet that WHERE the co-worker went, and what he did while there, was more important to getting and spreading C-19 upon his return to the home office than the actual airplane, but to show that would require robust contact tracing which probably still is not adequately in place.

The Irish airplane cluster article I linked is a good illustration of the impossibility of certitude. My money is on exposure occurring pre-flight. Of course only genetic sequencing could confirm that. During the winter surge, 20% of Angelenos were testing positive so a quarter of passengers boarding a flight covid+ isn't outside the realm of possibility.

Only 17% of seats were occupied during the flight and most passengers wore masks on board. Still, 13 of the 49 passengers eventually tested positive; at least nine reported to be wearing masks throughout the flight.