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Omicron largely evades immunity from past infection or two vaccine doses

imperial.ac.uk

11–20 of 161 posts

Re: Omicron largely evades immunity from past infection or two vaccine doses

#11
post #8

From the article: this translates into vaccine effectiveness estimates against symptomatic Omicron infection of between 0% and 20% after two doses, and between 55% and 80% after a booster dose What I'm wondering is: Is this due to the timing of a booster, since most boosters have been given in the last few months? Or is there some kind of cumulative impact on the immune system? Eg, If I got a booster early, am I stil…

Maybe recency is not the sole factor: https://i.imgur.com/OzznuBa.png

edit: source: https://www.medrxiv.org/content/10.1101/2021.12.14.21267769v...

Re: Omicron largely evades immunity from past infection or two vaccine doses

#12
Does anyone understand why a third dose of the same vaccine improves immunity to Omicron?

I'm willing to believe the empirical evidence that boosters make a meaningful difference, but I can't figure out intuitively why the same mRNA a third time helps to address this new spike.

Re: Omicron largely evades immunity from past infection or two vaccine doses

#13
post #8

From the article: this translates into vaccine effectiveness estimates against symptomatic Omicron infection of between 0% and 20% after two doses, and between 55% and 80% after a booster dose What I'm wondering is: Is this due to the timing of a booster, since most boosters have been given in the last few months? Or is there some kind of cumulative impact on the immune system? Eg, If I got a booster early, am I stil…

Or, another hypothesis, your immune system is busy dealing with the vaccine and just ignores the omicron virus in your noes and this stops the spread?

Re: Omicron largely evades immunity from past infection or two vaccine doses

#14
Realistically we are probably going to be exposed to Omicron in the next 3 weeks here in the UK, is there much point in having a booster right now? Are we sure that it will actually be providing protection if I got a booster today and got COVID in, say, the next 7 days?

Re: Omicron largely evades immunity from past infection or two vaccine doses

#15
This news came out shortly after the UK mandated proof of two vaccine doses (or a negative test, though there's some suspicion this option will be removed like in many other European countries) for access to nightclubs and other large events. It is also not surprising and was expected when the decision was taken. Between this and other recent news I don't think trust in the establishment is exactly high right now.

Re: Omicron largely evades immunity from past infection or two vaccine doses

#16

Does anyone understand why a third dose of the same vaccine improves immunity to Omicron? I'm willing to believe the empirical evidence that boosters make a meaningful difference, but I can't figure out intuitively why the same mRNA a third time helps to address this new spike.

Maybe it is less about it being the 2nd or 3rd shot and more about how recently you received your last shot? I got my 2nd shot 7 months ago and we've already heard that protection fades over time, so maybe the booster just works because it boosts, not because it is really any different than my 2nd shot.

Re: Omicron largely evades immunity from past infection or two vaccine doses

#17

Realistically we are probably going to be exposed to Omicron in the next 3 weeks here in the UK, is there much point in having a booster right now? Are we sure that it will actually be providing protection if I got a booster today and got COVID in, say, the next 7 days?

Probably some, if not the full amount.

Re: Omicron largely evades immunity from past infection or two vaccine doses

#18

Realistically we are probably going to be exposed to Omicron in the next 3 weeks here in the UK, is there much point in having a booster right now? Are we sure that it will actually be providing protection if I got a booster today and got COVID in, say, the next 7 days?

Sure. The effectiveness of the vaccine rises over time, which means you will have some protection even after a few days. And the vaccine also protects against serious illness, so if you get covid in 7 days you might be wishing for lighter symptoms about a week after that. Basically, getting your immune system any amount of head start would be great.

Re: Omicron largely evades immunity from past infection or two vaccine doses

#19

Does anyone understand why a third dose of the same vaccine improves immunity to Omicron? I'm willing to believe the empirical evidence that boosters make a meaningful difference, but I can't figure out intuitively why the same mRNA a third time helps to address this new spike.

I am not an immunologist, but I imagine repeated infection is a signal to the body to build and expand immunity to the virus.

Re: Omicron largely evades immunity from past infection or two vaccine doses

#20

Does anyone understand why a third dose of the same vaccine improves immunity to Omicron? I'm willing to believe the empirical evidence that boosters make a meaningful difference, but I can't figure out intuitively why the same mRNA a third time helps to address this new spike.

Is it not just timing? I thought the effectiveness of the vaccines only lasted around 6 months. In the US 18+ were able to get it 7 or 8 months ago.
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