mindstalk | Entries tagged with immune system

Importance of fit-testing your mask and not relying on "the seal feels good": ~75% of people who failed a fit test, passed a seal check. Jump to Table 3 to save time: https://journals.sagepub.com/doi/full/10.1177/0310057X20974022

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And finally, a very long paper on why some vaccines suck and others are one-and-done. Had a lot of new info even for me, even without getting too technical. https://deplatformdisease.substack.com/p/some-vaccines-are-one-and-done-why Some highlights:

I've been right! Reproduction dynamics are a key part to how good our protection is; if a virus reaches infectiousness faster than our memory B cells respond, we can't control it. Delta was faster than original covid and Omicron even faster.

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Paper 1: https://twitter.com/ENirenberg/status/1496294352594915328 (summary, but also has direct link to PDF.)

bad news: antibodies decline a lot after 3 months.

good? news: that's not a covid vaccine thing, it's an immune system thing. Infection antibodies come from short-lived plasmablasts, that pump out a flood of antibodies, then die on schedule. Then you have long-lived plasma cells that trickle out antibodies, and memory B cells that will spawn more short-lived cells 4-6 days after a new infection, which is a lot better than the 2-3 weeks to get antibodies to a novel antigen.

good news: memory B cells increase over time -- 10x as many 9 months later, compared to right after the second covid dose.

bad news not in this paper: omicron can propagate in 2-3 days. By the time your B cells respond, you've infected people and *they've* infected more people. I've mentioned this before.

other news: unvacced, 28 +/- 15 days from first positive swab to first negative PCR test; 20 +- 9 days for vacc.

Paper 2: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1009509
I've linked to this before, but it deserves a second pass. The key table is replicated here https://twitter.com/jmcrookston/status/1498877041105674240

The author says that all the viral diseases we develop lasting immunity against infection to, need to pass through our blood/lymph to transmit. I don't remember him spelling out exactly why, and I see two possibilities: one is that passing through the blood in itself exposes viruses to more of our immune system; the other is that passing through blood intrinsically takes longer than being able to transmit from respiratory cells alone. If I knew of any fast blood diseases or slow respiratory-only diseases, that would help differentiate the mechanisms. (Measles has a 12 day generation time; influenza may have 2 days, though other sources say 3.6. Wiki says typically 1-2 days.)

[Edit 2022-04-12: couple of money quotes:

"even natural respiratory infections with measles or variola (smallpox) viruses, famous for inducing life-long immunity to disease, do not prevent respiratory reinfection,"

"What polio-, variola, and measles virus share is dissemination from the initial infection site via lymph and (secondarily) blood as an obligate step in pathogenesis or transmission." ]

At any rate, since covid-19 has a generation time of just a few days, down to 2 for omicron, and does not need to pass through blood to transmit, we get the same result: lasting immunity to covid-19 infections is impossible. And people have done challenges with less alarming coronaviruses: "Human challenge studies established that seasonal CoV [coronavirus] reinfection with the identical strain can occur within a year after initial exposure, though typically with reduced shedding and milder symptoms."

Put another way, if the only thing between a virus and transmission is mucosal antibody levels, the virus will eventually transmit. As opposed to diseases like measles or polio where B and T cells must be crossed before transmission.

Seems to me that covid-19 is a "worst of both worlds" virus. It doesn't need the rest of our bodies to propagate, so it can transmit quickly and repeatedly, uncurbed by memory B cell responses. But thanks to the cell receptor it uses, it *can* randomly wander off to infect any organ of our bodies (vs. some cold virus that infected our noses but *stayed there*.) Influenza may also be such a virus (family)... and hey, influenza can be pretty deadly too.

On top of that, covid-19 has the killer app of suppressing initial innate immune response (something about blocking or inhibiting interferon production), which is why it has such a long pre-symptomatic infectious period, and probably part of why even partial NPIs (non-pharmaceutical intervention, masking and staying home and such) that failed to contain covid were able to crush flu and cold transmission.

And that's the virus that world leaders have decided we can just let rip, trusting entirely to our vaccines, despite not having a clear view of how much vaccines protect against long covid/blood clots/organ damage.

Dunno about you, but I'm still wearing respirators and not dining out.

Simplistically, you get 3 main benefits from infection or vaccination: antibodies which circulate in your body, and can respond right away to invaders; memory B cells, which make more antibodies ("secondary response") but take a few days to activate (I found various claims, from 4-7 days to 24-48 hours, so I can't be more precise); and killer T cells, which will purge infected cells, and I've got nothing about their response time except obviously *after* infection.

Ideally, the circulating antibodies stop re-infection cold. But antibody levels drop naturally, and we particularly don't seem to keep high levels in our mucus membranes, so there's a high chance that a respiratory disease is *not* stopped cold. What happens next?

In the case of measles, its generation time (from you being infected to you infecting someone else) is maybe 11-12 days. So even if an 'immune' person is breached, that infection will have to face a fully mobilized immune system, secondary response and killer T and all, so it probably gets clobbered before it can propagate. One breakthrough infection doesn't lead to more.

But in the case of covid, the generation time is just a few days, maybe only 2 days for Omicron. So it's possible that by the time your memory B cells get to work, not only have you infected more people, but those people have infected another wave of people in turn. Your T cells and any new antibodies will probably beat down the rest of the illness and keep it from killing you, but for infection-control purposes it's too late.

Is covid uniquely fast? Probably not: this says "The generation time is the doubling time, or the time required for the number of infections to double in size. Epidemiologic field studies of novel H1N1 flu infections in several states indicate that the generation time for acute respiratory illness (ARI) was 2.0-3.1 days and 2.4-3.1 days for influenza like illness (ILI)."

Flu, of course, is another disease that's been hard to contain via vaccination, for various reasons. But I would now guess that the main hope of a flu shot protecting you is from the initial wave of antibodies; if you were exposed to the exact same virus a year later, you would be counting on memory B cell protection, and likely get (mildly) sick.

I spent 2-3 hours late night reading vaccine stuff instead of going to bed. Might as well share! This is more basic and general stuff, not much about covid.

( Probably will be long )

Crossposts: https://mindstalk.livejournal.com/589932.html

Rich and Strange Aeons

Entries tagged with immune system

some health related papers

covid, B cells, and herd immunity

why stopping covid is hard

virus and vaccine reading notes

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