4 ms·

Something on the order of 1e4 children aged 0–9 have died from Covid-19 so far, worldwide. They face ~3 orders of magnitude less risk than elderly people (of w

Something on the order of 1e4 children aged 0–9 have died from Covid-19 so far, worldwide. They face ~3 orders of magnitude less risk than elderly people (of whom ~1e7 have died so far), but it is still nontrivial and much higher than the risks from vaccination. Small kids also spread Covid effectively. There have been a bunch of places with high vaccination rates where there were outbreaks in daycares. > It has been said [the vaccine] reduces spread, but this is not what you observe This is what you observe. There have been a large number of studies published examining the effects of vaccination rate on community spread showing that the reproductive number of the virus (at least the original and alpha/delta strains) is significantly depressed by vaccination. With omicron, vaccine effectiveness vs. initial infection / mild disease is much worse than with previous Covid variants (though it seems that protection vs. severe disease / death is still robust), so we can expect to see significant spread in highly vaccinated areas, but still less and slower than among an unvaccinated population.

johnisgood 5y ago
Well, a reply (from cudgy) to my comment says this: > The vaccine does not prevent spread of Covid. Period. The smallest amount of research proves this to be the case. So what is the truth?
- jacobolus 5y ago
  The commenter cudgy who posted that clearly did not do nontrivial research on this question from reliable sources. The statement is flat out false. The vaccines significantly reduce the chance of infection given identical exposure. For those who still get infected, the vaccines reduce the viral load throughout the infection, eliminate or ameliorate symptoms, and shorten the time during which an infected person is contagious. They do not completely prevent any spread of the virus (nor does any other vaccine ever created for any disease), but they make a significant beneficial impact on the rate of spread. They both cut the rate of secondary infections within each household, and reduce the amount of inter-household spread in the community.
  - johnisgood 5y ago
    > Vaccination reduces the risk of delta variant infection and accelerates viral clearance. Nonetheless, fully vaccinated individuals with breakthrough infections have peak viral load similar to unvaccinated cases and can efficiently transmit infection in household settings, including to fully vaccinated contacts. Host–virus interactions early in infection may shape the entire viral trajectory. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00648-4/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3...
    - jacobolus 5y ago
      That doesn’t contradict what I wrote, though obviously there is a lot more detail and nuance that could be added here. A few months after the second dose, 2 doses of the mRNA vaccines is insufficient to reduce peak viral load for breakthrough infections by the delta variant of the virus, making the vaccine less effective over time at preventing basic transmission and mild illness (the 2-dose vaccine was more effective with previous variants). However, a booster dose seems to make a significant improvement: > By analyzing viral loads of over 16,000 infections during the current, Delta-variant-dominated pandemic wave in Israel, we found that BTIs in recently fully vaccinated individuals have lower viral loads than infections in unvaccinated individuals. However, this effect starts to decline 2 months after vaccination and ultimately vanishes 6 months or longer after vaccination. Notably, we found that the effect of BNT162b2 on reducing BTI viral loads is restored after a booster dose. These results suggest that BNT162b2 might decrease the infectiousness of BTIs even with the Delta variant, and that, although this protective effect declines with time, it can be restored, at least temporarily, with a third, booster, vaccine dose. https://www.nature.com/articles/s41591-021-01575-4 https://www.nature.com/articles/s41591-021-01575-4 * * * For the omicron variant, there is still further reduced effectiveness of these vaccines on basic transmission and mild illness (only 70% effectiveness after a 3 shots; I don’t think there’s much data yet about viral loads), though protection against severe illness should still be robust (but reliable data about this will not be available for another few weeks or months).
      - johnisgood 5y ago

johnisgood 5y ago

Well, a reply (from cudgy) to my comment says this: > The vaccine does not prevent spread of Covid. Period. The smallest amount of research proves this to be the case. So what is the truth?

jacobolus 5y ago
The commenter cudgy who posted that clearly did not do nontrivial research on this question from reliable sources. The statement is flat out false. The vaccines significantly reduce the chance of infection given identical exposure. For those who still get infected, the vaccines reduce the viral load throughout the infection, eliminate or ameliorate symptoms, and shorten the time during which an infected person is contagious. They do not completely prevent any spread of the virus (nor does any other vaccine ever created for any disease), but they make a significant beneficial impact on the rate of spread. They both cut the rate of secondary infections within each household, and reduce the amount of inter-household spread in the community.
- johnisgood 5y ago
  > Vaccination reduces the risk of delta variant infection and accelerates viral clearance. Nonetheless, fully vaccinated individuals with breakthrough infections have peak viral load similar to unvaccinated cases and can efficiently transmit infection in household settings, including to fully vaccinated contacts. Host–virus interactions early in infection may shape the entire viral trajectory. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00648-4/fulltext https://www.thelancet.com/journals/laninf/article/PIIS1473-3...
  - jacobolus 5y ago
    That doesn’t contradict what I wrote, though obviously there is a lot more detail and nuance that could be added here. A few months after the second dose, 2 doses of the mRNA vaccines is insufficient to reduce peak viral load for breakthrough infections by the delta variant of the virus, making the vaccine less effective over time at preventing basic transmission and mild illness (the 2-dose vaccine was more effective with previous variants). However, a booster dose seems to make a significant improvement: > By analyzing viral loads of over 16,000 infections during the current, Delta-variant-dominated pandemic wave in Israel, we found that BTIs in recently fully vaccinated individuals have lower viral loads than infections in unvaccinated individuals. However, this effect starts to decline 2 months after vaccination and ultimately vanishes 6 months or longer after vaccination. Notably, we found that the effect of BNT162b2 on reducing BTI viral loads is restored after a booster dose. These results suggest that BNT162b2 might decrease the infectiousness of BTIs even with the Delta variant, and that, although this protective effect declines with time, it can be restored, at least temporarily, with a third, booster, vaccine dose. https://www.nature.com/articles/s41591-021-01575-4 https://www.nature.com/articles/s41591-021-01575-4 * * * For the omicron variant, there is still further reduced effectiveness of these vaccines on basic transmission and mild illness (only 70% effectiveness after a 3 shots; I don’t think there’s much data yet about viral loads), though protection against severe illness should still be robust (but reliable data about this will not be available for another few weeks or months).
    - johnisgood 5y ago