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Amazing that people will be getting vaccinated against coronavirus before the year is out. Is there any evidence of whether these vaccines prevent transmissio

Amazing that people will be getting vaccinated against coronavirus before the year is out. Is there any evidence of whether these vaccines prevent transmission of the virus yet? Or so far do we just know that they protect the person who is vaccinated?

redisman 6y ago
I’m also interested is the mRNA vaccine different or the same vis-a-vis stopping(or not) transmission
concerned_user 6y ago
It is planned that it requires 6 weeks to acquire immunity with 2 shots (4 weeks apart) of this vaccine. Realistic outcome if enough people get vaccinated should be that spring/summer wave of covid is suppressed or at least death rate and amount of severe cases will be much lower.
pjc50 6y ago
If you're not actually infected, i.e. you're protected, you don't spread the virus. I'm not aware of a disease for which this isn't true, that vaccinated people can be carriers.
- mssundaram 6y ago
  It's a bacteria and not a virus, but it's true for whooping cough, as one example.
- _Microft 6y ago
  What I remember but cannot currently find a source for, is that there are three levels of protection that vaccines can provide. First is to protect patients from developing the sickness (but not from being infected!), second is to even prevent them from spreading it and best outcome is to prevent them getting infected at all. Only the second and third level prevent spread.
- apendleton 6y ago
  Vaccines that prevent disease symptoms but don't completely prevent infection are definitely a thing (they're said to confer "non-sterilizing immunity," vs. "sterilizing immunity" which prevents both infection and disease). The inactivated polio vaccine (the injectable one that's used in the US) is an example of such a vaccine. The oral polio vaccine, which is the main one used in the developing world, interestingly does confer sterilizing immunity, but with the tradeoff that sometimes it also causes polio. At least in the US, the explicit target endpoint for FDA approval was just prevention of disease, not prevention of infection, and the phase III trials for both the Moderna and Pfizer/BioNTech trials were only designed to assess this criterion: they only tested symptomatic people, so it's entirely possible (though not that likely given animal model observations, etc.), that infections were just as common in the treatment groups as control groups, but they just never developed symptoms and so were never tested. More research will be needed to ascertain which kind of immunity is being conferred.
  - acqq 6y ago
    The researchers joke that "animals lie", in the sense that animals can have different reactions compared to humans, in spite of the researchers trying as much as possible to get something useful in the experiments. Having said that, I still believe your claim of what can be concluded to be unlikely based on "animal model observation" is false, from what is known up to now. Specifically: https://www.medscape.com/viewarticle/941030?src=soc_tw_201118_mscpedt_news_mdscp_vaccine&faf=1 https://www.medscape.com/viewarticle/941030?src=soc_tw_20111... "In an ideal world, a vaccine would prevent infection entirely and, it follows, also prevent disease and severe disease. But this may be hard to achieve for a respiratory virus vaccine. Animal challenge data suggest that vaccinated animals may still be infected even if they don't experience symptoms. A vaccine that is able to reduce the severity of disease, even if it cannot prevent infection entirely, would obviously still have enormous public health value. Therefore, this is what trials target as their primary aim." I suggest everybody to read carefully the whole article, as it is written by an indisputable expert, and what is presented in the article isn't based only on the animal models but on much broader knowledge. Nobody at this moment should expect that the vaccines guarantee that somebody who is vaccinated won't be able to infect somebody who hasn't received a vaccine. That, for example, means that even if the health workers do get a vaccine they will still have to wear protective equipment.
- thinkingemote 6y ago
  > If you're not actually infected, The question is whether the vaccine against covid prevents people from getting infected with the virus or whether the vaccine protects against the effects of the Covid disease. This is not the same.

redisman 6y ago

I’m also interested is the mRNA vaccine different or the same vis-a-vis stopping(or not) transmission

concerned_user 6y ago

It is planned that it requires 6 weeks to acquire immunity with 2 shots (4 weeks apart) of this vaccine. Realistic outcome if enough people get vaccinated should be that spring/summer wave of covid is suppressed or at least death rate and amount of severe cases will be much lower.

pjc50 6y ago

If you're not actually infected, i.e. you're protected, you don't spread the virus. I'm not aware of a disease for which this isn't true, that vaccinated people can be carriers.

mssundaram 6y ago
It's a bacteria and not a virus, but it's true for whooping cough, as one example.
_Microft 6y ago
What I remember but cannot currently find a source for, is that there are three levels of protection that vaccines can provide. First is to protect patients from developing the sickness (but not from being infected!), second is to even prevent them from spreading it and best outcome is to prevent them getting infected at all. Only the second and third level prevent spread.
apendleton 6y ago
Vaccines that prevent disease symptoms but don't completely prevent infection are definitely a thing (they're said to confer "non-sterilizing immunity," vs. "sterilizing immunity" which prevents both infection and disease). The inactivated polio vaccine (the injectable one that's used in the US) is an example of such a vaccine. The oral polio vaccine, which is the main one used in the developing world, interestingly does confer sterilizing immunity, but with the tradeoff that sometimes it also causes polio. At least in the US, the explicit target endpoint for FDA approval was just prevention of disease, not prevention of infection, and the phase III trials for both the Moderna and Pfizer/BioNTech trials were only designed to assess this criterion: they only tested symptomatic people, so it's entirely possible (though not that likely given animal model observations, etc.), that infections were just as common in the treatment groups as control groups, but they just never developed symptoms and so were never tested. More research will be needed to ascertain which kind of immunity is being conferred.
- acqq 6y ago
  The researchers joke that "animals lie", in the sense that animals can have different reactions compared to humans, in spite of the researchers trying as much as possible to get something useful in the experiments. Having said that, I still believe your claim of what can be concluded to be unlikely based on "animal model observation" is false, from what is known up to now. Specifically: https://www.medscape.com/viewarticle/941030?src=soc_tw_201118_mscpedt_news_mdscp_vaccine&faf=1 https://www.medscape.com/viewarticle/941030?src=soc_tw_20111... "In an ideal world, a vaccine would prevent infection entirely and, it follows, also prevent disease and severe disease. But this may be hard to achieve for a respiratory virus vaccine. Animal challenge data suggest that vaccinated animals may still be infected even if they don't experience symptoms. A vaccine that is able to reduce the severity of disease, even if it cannot prevent infection entirely, would obviously still have enormous public health value. Therefore, this is what trials target as their primary aim." I suggest everybody to read carefully the whole article, as it is written by an indisputable expert, and what is presented in the article isn't based only on the animal models but on much broader knowledge. Nobody at this moment should expect that the vaccines guarantee that somebody who is vaccinated won't be able to infect somebody who hasn't received a vaccine. That, for example, means that even if the health workers do get a vaccine they will still have to wear protective equipment.
thinkingemote 6y ago
> If you're not actually infected, The question is whether the vaccine against covid prevents people from getting infected with the virus or whether the vaccine protects against the effects of the Covid disease. This is not the same.