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I'm confused. Weren't covid mRNA vaccines very effective at preventing infection, even asymptomatic infection, against delta and earlier variants? Only with omi

by jmckib 5y ago

I'm confused. Weren't covid mRNA vaccines very effective at preventing infection, even asymptomatic infection, against delta and earlier variants? Only with omicron has the effectiveness been significantly reduce, but not to zero. And once we come up with a variant-specific vaccine, I would expect the effectiveness to go up again.

jdrc 5y ago
The efficiency of vaccines for infection fell by 50% in 4 monts even for delta and other variants. Their effectiveness with omicron infection is very little. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02183-8/fulltext https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
- jmckib 5y ago
  50% effectiveness against infection is still pretty significant. And note that OP said "essentially no viral vaccine prevents infection." I think we can agree that is not the case.
- r2_pilot 5y ago
  I've been exposed twice with known-omicron and have not gotten sick yet. YMMV.
Izkata 5y ago
No, they were very effective at preventing symptomatic covid. This can mean either preventing infection or not preventing infection but just stopping symptoms. The trials that came up with that 94% efficacy never tested for which of these two outcomes it was, and it turns out it was mostly the second one, which allows for asymptomatic spreading.
- jmckib 5y ago
  No, the vaccines were very effective at preventing any infection, both symptomatic and asymptomatic. There were studies done by giving the participants regular covid tests, usually once a week, so they would catch asympomatic cases as well. Here are the conclusions from a meta-study from July 2021: > In fully vaccinated individuals, VE against symptomatic and asymptomatic infections was 80–90% in nearly all studies. https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC8284046/ https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC8284046/

by jmckib 5y ago

jdrc 5y ago

The efficiency of vaccines for infection fell by 50% in 4 monts even for delta and other variants. Their effectiveness with omicron infection is very little. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02183-8/fulltext https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

jmckib 5y ago
50% effectiveness against infection is still pretty significant. And note that OP said "essentially no viral vaccine prevents infection." I think we can agree that is not the case.
r2_pilot 5y ago
I've been exposed twice with known-omicron and have not gotten sick yet. YMMV.

Izkata 5y ago

No, they were very effective at preventing symptomatic covid. This can mean either preventing infection or not preventing infection but just stopping symptoms. The trials that came up with that 94% efficacy never tested for which of these two outcomes it was, and it turns out it was mostly the second one, which allows for asymptomatic spreading.

jmckib 5y ago
No, the vaccines were very effective at preventing any infection, both symptomatic and asymptomatic. There were studies done by giving the participants regular covid tests, usually once a week, so they would catch asympomatic cases as well. Here are the conclusions from a meta-study from July 2021: > In fully vaccinated individuals, VE against symptomatic and asymptomatic infections was 80–90% in nearly all studies. https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC8284046/ https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC8284046/