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Vaccines have never "prevented" transmission absolutely, so 100%. They have always "prevented" transmission in some cases, so reducing transmission. At slightl

Vaccines have never "prevented" transmission absolutely, so 100%. They have always "prevented" transmission in some cases, so reducing transmission. At slightly lower rates than preventing severe outcomes. Delta was 2x more transmissible than the first strain of Covid. Omicron appears to be around 4x more transmissible than delta, so 8x more transmissible than the original variant. Even if the vaccines had been 90% effective at reducing transmission and was just as effective against Omicron, we would expect Omicron to spread in a fully vaccinated/boostered population just as quickly as the original variant spread in a completely unvaccinated population. However, the vaccines were not 90% effective at preventing transmission of the original variant, more like 60-80% IIRC. And Omicron has mutated significantly, so effectiveness is further reduced. And of course there is a significant percentage of unvaccinated (partly due to "the vaccines don't work misinformation, sigh!), and the virus has a much easier time going from unvaccinated → vaccinated or vaccinated → unvaccinated than it does going from vaccinated → vaccinated. So seeing high(er) transmission rates right now in no way "proves" that the "vaccines don't work at preventing transmission". Neither do anecdotes that do not contradict the actual evidence. Transmission rates would be a lot higher without vaccines.

ls15 5y ago
> However, the vaccines were not 90% effective at preventing transmission of the original variant, more like 60-80% IIRC. And Omicron has mutated significantly, so effectiveness is further reduced. And of course there is a significant percentage of unvaccinated (partly due to "the vaccines don't work misinformation, sigh!), and the virus has a much easier time going from unvaccinated → vaccinated or vaccinated → unvaccinated than it does going from vaccinated → vaccinated. Now Omicron is dominant and these earlier strains are not relevant anymore. It is reasonable to expect that the virus will mutate more and faster, maybe even with many different strains that are relevant at the same time. > And of course there is a significant percentage of unvaccinated (partly due to "the vaccines don't work misinformation, sigh!) Most of Africa is unvaccinated, because they don't have the vaccine, while some countries are trying to enforce the third injection. > Transmission rates would be a lot higher without vaccines. That is not an argument for mandating vaccines when they only prevent the spread of the currently dominant strains with a very low probability or maybe even not at all. Actually I haven't heard of any good argument for that yet.
- mpweiher 5y ago
  > Now Omicron is dominant and these earlier strains are not relevant anymore. Yes they are, when explaining why "it's spreading quickly now" does not imply that the vaccines aren't effective. They are. >> It is common knowledge by now, January 2022, that SARS-CoV-2 vaccines do not prevent transmission of SARS-CoV-2. And when you stop spreading misinformation like this, I will stop correcting you. > Most of Africa is unvaccinated What relevance does this have to your false claim that the "vaccines do not prevent transmission"? > > Transmission rates would be a lot higher without vaccines. > That is not an argument for mandating vaccines You are right that it is not. Fortunately, that is not the reasoning for vaccine mandates, but just a rebuttal of your misinformation, such as: > they only prevent the spread of the currently dominant strains with a very low probability or maybe even not at all. No, they do not prevent spread at "very low" probability. Omicron is just much, much more contagious, so even with pretty high probability of prevention the rate of spread is high. This is why comparing with older variants is helpful with understanding the current situation. You are also making the mistake of thinking of the effectiveness as a completely independent variable. But it is not. Overall effectiveness rises as the vaccination rates increase, because vaccinated → vaccinated has a lower probability of transmission than vaccinated → unvaccinated or unvaccinated → vaccinated. And since Omicron is so much more transmissible than Delta, never mind Alpha, getting to a higher vaccination rate is more important than ever in achieving the desired societal outcomes. Furthermore, every sick person puts a stress on the health system. With Omicron being so incredibly contagious, the risk of overwhelming the health system rises, meaning that other people suffer when you become sick, even if you don't infect anyone. > Actually I haven't heard of any good argument for that yet. Then you're not paying attention.
  - jules 5y ago
    100% vaccination rate would still have R>1. While that is unfortunate, they are right and you are not.
    - mpweiher 5y ago
      a) We don't actually know that. b) I doubt that it is true, though Omicron is a tough one. c) The reason I doubt it is that this is a nonlinear effect, i.e. you cannot easily extrapolate from vaccine effectiveness at 65% vaccination rate to vaccine effectiveness at 91%, 99%, or 100%. d) The more contagious the virus, the higher your vaccination rate needs to be, for reasons that I hope are obvious. e) So, seemingly paradoxically, the more the vaccine seems to not be working (it actually still is, the virus is just mostly much more contagious), the better the case for vaccine mandates. We really, really need to starve the virus of hosts, particularly so we don't breed ever more variants. f) Even if it were true that R would still be > 1 with a 100% vaccination rate, as long as the R rate is lower with the vaccines than it is without the vaccines, the vaccines are preventing (some) transmission.

ls15 5y ago

> However, the vaccines were not 90% effective at preventing transmission of the original variant, more like 60-80% IIRC. And Omicron has mutated significantly, so effectiveness is further reduced. And of course there is a significant percentage of unvaccinated (partly due to "the vaccines don't work misinformation, sigh!), and the virus has a much easier time going from unvaccinated → vaccinated or vaccinated → unvaccinated than it does going from vaccinated → vaccinated. Now Omicron is dominant and these earlier strains are not relevant anymore. It is reasonable to expect that the virus will mutate more and faster, maybe even with many different strains that are relevant at the same time. > And of course there is a significant percentage of unvaccinated (partly due to "the vaccines don't work misinformation, sigh!) Most of Africa is unvaccinated, because they don't have the vaccine, while some countries are trying to enforce the third injection. > Transmission rates would be a lot higher without vaccines. That is not an argument for mandating vaccines when they only prevent the spread of the currently dominant strains with a very low probability or maybe even not at all. Actually I haven't heard of any good argument for that yet.

mpweiher 5y ago
> Now Omicron is dominant and these earlier strains are not relevant anymore. Yes they are, when explaining why "it's spreading quickly now" does not imply that the vaccines aren't effective. They are. >> It is common knowledge by now, January 2022, that SARS-CoV-2 vaccines do not prevent transmission of SARS-CoV-2. And when you stop spreading misinformation like this, I will stop correcting you. > Most of Africa is unvaccinated What relevance does this have to your false claim that the "vaccines do not prevent transmission"? > > Transmission rates would be a lot higher without vaccines. > That is not an argument for mandating vaccines You are right that it is not. Fortunately, that is not the reasoning for vaccine mandates, but just a rebuttal of your misinformation, such as: > they only prevent the spread of the currently dominant strains with a very low probability or maybe even not at all. No, they do not prevent spread at "very low" probability. Omicron is just much, much more contagious, so even with pretty high probability of prevention the rate of spread is high. This is why comparing with older variants is helpful with understanding the current situation. You are also making the mistake of thinking of the effectiveness as a completely independent variable. But it is not. Overall effectiveness rises as the vaccination rates increase, because vaccinated → vaccinated has a lower probability of transmission than vaccinated → unvaccinated or unvaccinated → vaccinated. And since Omicron is so much more transmissible than Delta, never mind Alpha, getting to a higher vaccination rate is more important than ever in achieving the desired societal outcomes. Furthermore, every sick person puts a stress on the health system. With Omicron being so incredibly contagious, the risk of overwhelming the health system rises, meaning that other people suffer when you become sick, even if you don't infect anyone. > Actually I haven't heard of any good argument for that yet. Then you're not paying attention.
- jules 5y ago
  100% vaccination rate would still have R>1. While that is unfortunate, they are right and you are not.
  - mpweiher 5y ago
    a) We don't actually know that. b) I doubt that it is true, though Omicron is a tough one. c) The reason I doubt it is that this is a nonlinear effect, i.e. you cannot easily extrapolate from vaccine effectiveness at 65% vaccination rate to vaccine effectiveness at 91%, 99%, or 100%. d) The more contagious the virus, the higher your vaccination rate needs to be, for reasons that I hope are obvious. e) So, seemingly paradoxically, the more the vaccine seems to not be working (it actually still is, the virus is just mostly much more contagious), the better the case for vaccine mandates. We really, really need to starve the virus of hosts, particularly so we don't breed ever more variants. f) Even if it were true that R would still be > 1 with a 100% vaccination rate, as long as the R rate is lower with the vaccines than it is without the vaccines, the vaccines are preventing (some) transmission.