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the pfizer vaccine doesn't prevent infection, but does save lives by preventing severe symptoms, which is why at-risk groups are prioritized. the vaccines that

the pfizer vaccine doesn't prevent infection, but does save lives by preventing severe symptoms, which is why at-risk groups are prioritized. the vaccines that actually prevent infection are still being developed. 2022 sounds realistic for that, if not a tad early.

n4r9 6y ago
What do you mean it "doesn't prevent infection"? Trials showed vastly reduced infection rate amongst people who'd had the vaccine.
- markburns 6y ago
  As a layperson I read “prevent” to mean a 100% reduction. Not sure if there’s a slightly different interpretation than that but I’d presume that’s what they mean?
  - officialjunk 6y ago
    Didn't have a link handy at the time. Read this https://www.forbes.com/sites/williamhaseltine/2020/09/23/covid-19-vaccine-protocols-reveal-that-trials-are-designed-to-succeed/ https://www.forbes.com/sites/williamhaseltine/2020/09/23/cov... "We all expect an effective vaccine to prevent serious illness if infected. Three of the vaccine protocols—Moderna, Pfizer, and AstraZeneca—do not require that their vaccine prevent serious disease only that they prevent moderate symptoms which may be as mild as cough, or headache." "Prevention of infection is not a criterion for success for any of these vaccines. In fact, their endpoints all require confirmed infections and all those they will include in the analysis for success, the only difference being the severity of symptoms between the vaccinated and unvaccinated."
    - zaroth 6y ago
      The Moderna vaccine, for example, “is highly effective in preventing symptomatic COVID.” They only did PCR testing on trial participants who reported symptoms. They did not PCR test the entire study population. Incidence of symptomatic COVID was dramatically halted by about Day 14 after the first dose: https://twitter.com/wgibson/status/1336298050315313158?s=21 https://twitter.com/wgibson/status/1336298050315313158?s=21
    - tim333 6y ago
      >the only difference being the severity of symptoms between the vaccinated and unvaccinated seems kind of wrong to me. The main difference they are hoping for is the number of cases of illness between the unvaccinated and vaccinated. If you get 100 cases in the unvaccinated group and 1 in the vaccinated it doesn't really matter if the symptoms are a bit better or worse.
- bagacrap 6y ago
  It prevented symptomatic covid, but we still don't know if it prevents transmission of the virus itself. It might just turn you into an asymptomatic spreader.
  - n4r9 6y ago
    Huh, you're correct, at least in the case of Pfizer. That's a pretty important bit of info that seemed to be missing in all the reporting I'd read until I googled for that specifically. I'd be surprised if it turned out that the vaccine simply dials down the symptoms, based on my understanding of vaccines, but I guess we can't rule it out yet.
  - zaroth 6y ago
    > Data are limited to assess the effect of the vaccine against transmission of SARS-CoV-2 from individuals who are infected despite vaccination. Demonstrated high efficacy against symptomatic COVID-19 may translate to overall prevention of transmission in populations with high enough vaccine uptake, though it is possible that if efficacy against asymptomatic infection were lower than efficacy against symptomatic infection, asymptomatic cases in combination with reduced mask-wearing and social distancing could result in significant continued transmission. Additional evaluations including data from clinical trials and from vaccine use post-authorization will be needed to assess the effect of the vaccine in preventing virus shedding and transmission, in particular in individuals with asymptomatic infection. What they are saying is that it is technically possible for their vaccine which is highly effective at preventing symptomatic COVID to be somehow ineffective at preventing asymptomatic COVID. https://www.fda.gov/media/144245/download https://www.fda.gov/media/144245/download
  - blackrock 6y ago
    What? This is the first I heard of this. The Pfizer vaccine is the mRNA vaccine. And it doesn’t prevent you from getting sick. But it might turn you into an asymptomatic spreader? Oh great. Do you have sources? This thing is going to turn us all into walking zombies. LOL.
    - deleted 6y ago
      [deleted]
ericb 6y ago
> doesn't prevent infection My understanding is not that it doesn't, just that this hasn't been proven yet.
spyridonas 6y ago
Aren't all the vaccines from all the companies designed as mRNA that teaches/instructs the body how to kill the virus ?
- dm319 6y ago
  The pfizer vaccine is mRNA, so when it goes into a cell it will use the translation machinery to convert to protein and that gets presented to the immune system. The Oxford vaccine uses a non-reproductive adenovirus to introduce the RNA into the cell, with a similar result. I think the Oxford one won't have issues with storage. There are others that use recombinant protein from the virus.

n4r9 6y ago

What do you mean it "doesn't prevent infection"? Trials showed vastly reduced infection rate amongst people who'd had the vaccine.

markburns 6y ago
As a layperson I read “prevent” to mean a 100% reduction. Not sure if there’s a slightly different interpretation than that but I’d presume that’s what they mean?
- officialjunk 6y ago
  Didn't have a link handy at the time. Read this https://www.forbes.com/sites/williamhaseltine/2020/09/23/covid-19-vaccine-protocols-reveal-that-trials-are-designed-to-succeed/ https://www.forbes.com/sites/williamhaseltine/2020/09/23/cov... "We all expect an effective vaccine to prevent serious illness if infected. Three of the vaccine protocols—Moderna, Pfizer, and AstraZeneca—do not require that their vaccine prevent serious disease only that they prevent moderate symptoms which may be as mild as cough, or headache." "Prevention of infection is not a criterion for success for any of these vaccines. In fact, their endpoints all require confirmed infections and all those they will include in the analysis for success, the only difference being the severity of symptoms between the vaccinated and unvaccinated."
  - zaroth 6y ago
    The Moderna vaccine, for example, “is highly effective in preventing symptomatic COVID.” They only did PCR testing on trial participants who reported symptoms. They did not PCR test the entire study population. Incidence of symptomatic COVID was dramatically halted by about Day 14 after the first dose: https://twitter.com/wgibson/status/1336298050315313158?s=21 https://twitter.com/wgibson/status/1336298050315313158?s=21
  - tim333 6y ago
    >the only difference being the severity of symptoms between the vaccinated and unvaccinated seems kind of wrong to me. The main difference they are hoping for is the number of cases of illness between the unvaccinated and vaccinated. If you get 100 cases in the unvaccinated group and 1 in the vaccinated it doesn't really matter if the symptoms are a bit better or worse.
bagacrap 6y ago
It prevented symptomatic covid, but we still don't know if it prevents transmission of the virus itself. It might just turn you into an asymptomatic spreader.
- n4r9 6y ago
  Huh, you're correct, at least in the case of Pfizer. That's a pretty important bit of info that seemed to be missing in all the reporting I'd read until I googled for that specifically. I'd be surprised if it turned out that the vaccine simply dials down the symptoms, based on my understanding of vaccines, but I guess we can't rule it out yet.
- zaroth 6y ago
  > Data are limited to assess the effect of the vaccine against transmission of SARS-CoV-2 from individuals who are infected despite vaccination. Demonstrated high efficacy against symptomatic COVID-19 may translate to overall prevention of transmission in populations with high enough vaccine uptake, though it is possible that if efficacy against asymptomatic infection were lower than efficacy against symptomatic infection, asymptomatic cases in combination with reduced mask-wearing and social distancing could result in significant continued transmission. Additional evaluations including data from clinical trials and from vaccine use post-authorization will be needed to assess the effect of the vaccine in preventing virus shedding and transmission, in particular in individuals with asymptomatic infection. What they are saying is that it is technically possible for their vaccine which is highly effective at preventing symptomatic COVID to be somehow ineffective at preventing asymptomatic COVID. https://www.fda.gov/media/144245/download https://www.fda.gov/media/144245/download
- blackrock 6y ago
  What? This is the first I heard of this. The Pfizer vaccine is the mRNA vaccine. And it doesn’t prevent you from getting sick. But it might turn you into an asymptomatic spreader? Oh great. Do you have sources? This thing is going to turn us all into walking zombies. LOL.
  - deleted 6y ago
    [deleted]

ericb 6y ago

> doesn't prevent infection My understanding is not that it doesn't, just that this hasn't been proven yet.

spyridonas 6y ago

Aren't all the vaccines from all the companies designed as mRNA that teaches/instructs the body how to kill the virus ?

dm319 6y ago
The pfizer vaccine is mRNA, so when it goes into a cell it will use the translation machinery to convert to protein and that gets presented to the immune system. The Oxford vaccine uses a non-reproductive adenovirus to introduce the RNA into the cell, with a similar result. I think the Oxford one won't have issues with storage. There are others that use recombinant protein from the virus.