Booster vaccination

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Woodchopper
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Booster vaccination

Post by Woodchopper » Thu Sep 23, 2021 12:14 pm

A good thread on 4 scenarios that result from giving a booster vaccine:
https://twitter.com/davidwdowdy/status/ ... 21568?s=20

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lpm
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Re: Booster vaccination

Post by lpm » Thu Sep 23, 2021 12:42 pm

Hmm.

The scenarios might be different for >80s. Or for Pfizer on top of 2 AZs.

I think his conclusion for C is wrong - it's the same as A. If it gives the elderly better protection for the coming 6 months, even if only a small increment on top of the already very good effectiveness against death, then booster now is important. Probably in the next few years there's never going to be a worse time than the coming six months. Going from, say, 90% protection for over 80s to 92% protection is pretty good death saving.
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PeteB
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Re: Booster vaccination

Post by PeteB » Thu Sep 23, 2021 1:30 pm

Yes, before you think about it 90->92 % sounds trivial but 10%->8% is quite a big change

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Brightonian
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Re: Booster vaccination

Post by Brightonian » Fri Oct 08, 2021 5:33 pm

Do we know yet how long it takes for a booster to become effective? Just had a Zoom session with my father (mid-80s) who's had his booster today and he was wondering about this. I can't find the answer myself so maybe there's just not enough data out there. And I suppose it depends which vaccine it is too (I assume in my father's case it's Pfizer as he initially had Pfizer).

Millennie Al
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Re: Booster vaccination

Post by Millennie Al » Sat Oct 09, 2021 1:17 am

I haven't seen any data, so I'd guess boosters need about two weeks to be fully effective just like the second dose of two-dose vaccines.
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sTeamTraen
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Re: Booster vaccination

Post by sTeamTraen » Sat Oct 09, 2021 5:57 pm

Brightonian wrote:
Fri Oct 08, 2021 5:33 pm
Do we know yet how long it takes for a booster to become effective? Just had a Zoom session with my father (mid-80s) who's had his booster today and he was wondering about this. I can't find the answer myself so maybe there's just not enough data out there. And I suppose it depends which vaccine it is too (I assume in my father's case it's Pfizer as he initially had Pfizer).
Efficacy is not a binary thing, and neither is the change in efficacy over time; it will be some kind of (presumably monotonic) function. Obviously governments have to say things like "In order for your vaccine to count for travel you must have had the final dose more than 2 weeks ago", but in reality your immunity will evolve over time in some kind of probability density function. (And your immunity is in turn is a probability density function with multiple parameters: how likely are you get how ill given exposure to how much of the virus.)

Also with boosters, we don't know what someone's pre- and post- immunity is, unless we run antibody tests to at least get a formal estimate of the prevalence of antibodies. At least with the first vaccine, for someone who hasn't had Covid, we can assume their pre-first-shot antibody count was probably zero.

tl;dr: Everything is about statistics at the population level, and there is still much we don't know. Boosters seem like a good risk/reward for vulnerable groups.
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jdc
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Re: Booster vaccination

Post by jdc » Sun Oct 10, 2021 1:29 am

Thread here on cellular immunity and immune memory may be of interest https://twitter.com/MonicaGandhi9/statu ... 3402408960

Seems that you (a) generate more antibodies and (b) generate them more quickly the second time you're exposed to the antigen compared with your first exposure.

Note the long-lasting nature of memory B ("no apparent half-life") and memory T cells ("long half-lives") also "80-100 T cells line up across spike protein so 10-13 mutations of variants can't escape T cells", "Memory B cells bind to conserved regions of the spike protein that are common to all variants" and "memory B cells adapt their antibodies they produce to the variant at hand".

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