Assuming the vaccine is ~95% effective two weeks after the second dose, does that mean 95% of the recipients are 100% immune to covid, or does that mean each recipient has a 95% chance of not getting covid every time they are exposed? I assume the former in which case can recipients have some type of follow up test to see whether they are in the 95% or the 5%?

It's judged by "moderate" illness I believe. So if you don't get sick you're not in the 5%. And if you "get" covid but need a test to find out, it doesn't really matter.

My understanding is that you have a 5% chance of becoming symptomatically infected if you are exposed. No data yet on your chances of becoming infected at all.

From what I have seen if you remain without symptoms 2 weeks post second shot it is 99.9% effective.

The 95% is derived by comparing the population of inoculated patients that came down with covid, to the population of patients that came down with covid in the (non-innoculated) control group.

It means you are 20 times less likely to get infected than someone without the vaccine.

As Fratboy mentioned, that's exactly how they calculate it. How many people got infected in the non-vaccine group or placebo group versus the vaccinated group.

If they had the two sides of the trial perfectly randomized and 100 people got infected in the placebo group, then 95% effective means only 5 people would have gotten infected in the vaccine group. I.E. Of the 100 people who "should" have gotten infected, 95% were protected by vaccine.

HotardAg07 said:

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It means you are 20 times less likely to get infected than someone without the vaccine.

As Fratboy mentioned, that's exactly how they calculate it. How many people got infected in the non-vaccine group or placebo group versus the vaccinated group.

If they had the two sides of the trial perfectly randomized and 100 people got infected in the placebo group, then 95% effective means only 5 people would have gotten infected in the vaccine group. I.E. Of the 100 people who "should" have gotten infected, 95% were protected by vaccine.

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I get that, my question is if the 95% who "should" have gotten the virus in that group but did not (the group who obtained the full vaccine benefits), are they now generally 100% immune from getting infected or do they just have a 95% chance of not getting infected when faced with each future covid exposure.

Said another way, if you are in that 95% group, are you increasing your odds of getting infected the more times you are exposed to Covid or has the vaccine simply worked as intended for you and you will not get it no matter how many times you are exposed.

Sounds like we may not know the answer to this question based on the limited data and studies so far.

my understanding is that there is a reason it is measured by Efficacy and not Effectiveness. It measures the occurance of potential outcomes from real world exposures.

If you would have been in the 95% group but got an unrealistically high viral dose, you could get sick. but from expsures levels that you would get in the normal activities, you would have been ok.

I am curious how/if reduced viral dosing from masking and social distancing inflated/deflated the efficacy of the vaccine.

SUag said:

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HotardAg07 said:

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It means you are 20 times less likely to get infected than someone without the vaccine.

As Fratboy mentioned, that's exactly how they calculate it. How many people got infected in the non-vaccine group or placebo group versus the vaccinated group.

If they had the two sides of the trial perfectly randomized and 100 people got infected in the placebo group, then 95% effective means only 5 people would have gotten infected in the vaccine group. I.E. Of the 100 people who "should" have gotten infected, 95% were protected by vaccine.

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I get that, my question is of the 95% who "should" have gotten the virus in that group but did not (the group who obtained the full vaccine benefits), are they now generally 100% immune from getting infected or do they just have a 95% chance of not getting infected when faced with each future covid exposure.

Said another way, if you are in that 95% group, are you increasing your odds of getting infected the more times you are exposed to Covid or has the vaccine simply worked as intended for you and you will not get it no matter how many times you are exposed.

Sounds like we may not know the answer to this question based on the limited data and studies so far.

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You are WAY overthinking this. 95% and 100% are effectively the same number in this situation.