What Does "Effective" Mean?

[DogNo1]

The various vaccine producers claim that their vaccine is X% effective.  What does "effective" mean?  

[PFMills]

in the case stated it basically means that it was close to having the desired result ie actually (100-X)% away from the desired result. . 

Edited December 6, 2020 by PFMills

[timendres]

9 minutes ago, DogNo1 said:

The various vaccine producers claim that their vaccine is X% effective.  What does "effective" mean?  

 

In general it means that the vaccine invokes an immune system response that causes your body to generate antibodies, t-cells, etc., aimed at the virus in question, in sufficient quantities to prevent the virus from successfully making you ill.

[DogNo1]

Given that Pfizer and Moderna have tested very few vaccine recipients, how can they make that claim?

[1FinickyOne]

5 minutes ago, DogNo1 said:

how can they make that claim?

Yo. Dog #1 - 

 

We live in a world of false claims and advertising as a daily affair... every dog food is going to be the best and your dog will love it... 

 

There was a dog food that used to claim - "all meat, not a speck of cereal... " to which Dave Letterman responded - 'my dog drinks from the toilet bowl, I don't think he will mind a speck of cereal.' 

 

So, the answer is that if not under oath and in a court of law, you can claim whatever you like... 

[mommysboy]

It's a good question. In my opinion it won't be true to say that any of these vaccines will prevent infection, but what they will undoubtedly do is prevent people from becoming seriously ill and dying; in this respect all 3 are highly effective. 

 

 

[DogNo1]

That's my understanding too.  The vaccines won't prevent infection but will prevent serious illness.  The problem is that many people and governments seem to assume that they WILL prevent infection.  This is relevant to quarantine policy.  If the vaccines don't prevent infection then quarantines should continue to be required.  Many business people would prefer this not to be the case.

[impulse]

24 minutes ago, DogNo1 said:

That's my understanding too.  The vaccines won't prevent infection but will prevent serious illness.  The problem is that many people and governments seem to assume that they WILL prevent infection.  This is relevant to quarantine policy.  If the vaccines don't prevent infection then quarantines should continue to be required.  Many business people would prefer this not to be the case.

 

The question then becomes, which is killing more people and ruining more lives, the virus or the economic devastation caused by the lockdowns?  It'll be years before we know the extent of damage from derailing people's careers and crushing millions of businesses.

 

[partington]

 

 

26 minutes ago, DogNo1 said:

That's my understanding too.  The vaccines won't prevent infection but will prevent serious illness.  The problem is that many people and governments seem to assume that they WILL prevent infection.  This is relevant to quarantine policy.  If the vaccines don't prevent infection then quarantines should continue to be required.  Many business people would prefer this not to be the case.

 

The trials do test infection rates. Ninety percent effective means that when you  compare Covid infection between the placebo group and the vaccinated group, the infection rate of the vaccinated group is 10% of the rate of the placebo group.

 

In some trials (eg Pfizer) infection rates are detected by testing people after they have reported symptoms to confirm they have SARS-CoV-2 infection.  This will miss infections that are symptomless.  In other trials (eg AstraZeneca) I believe all subjects are tested so all infections are picked up. In this case you can definitively state that infections are prevented, since the other results could be due to vaccination reducing symptoms to the point that they are not detectable, so not reported by the subjects.

 

I think this discussion is confusing "infection" with "transmission", which is a central issue.  If you are not infected you cannot transmit to someone else. If you are infected but the vaccine blocks virus replication and expansion so  much that you don't develop symptoms will it also prevent shedding of the virus from your body enough to stop you passing on the disease?

 

As far as I am aware there is no available data on this.

[Dagfinnur Traustason]

2 hours ago, DogNo1 said:

The various vaccine producers claim that their vaccine is X% effective.  What does "effective" mean?  

That´s easy. It means that the vaccine is effective (works) on X% of the tested persons. Just holler if ya thinking of anything else.

[impulse]

8 minutes ago, Dagfinnur Traustason said:

2 hours ago, DogNo1 said:

The various vaccine producers claim that their vaccine is X% effective.  What does "effective" mean?  

That´s easy. It means that the vaccine is effective (works) on X% of the tested persons. Just holler if ya thinking of anything else.

 

What does "works" mean in that context?

 

[onebir]

35 minutes ago, partington said:

If you are infected but the vaccine blocks virus replication and expansion so  much that you don't develop symptoms will it also prevent shedding of the virus from your body enough to stop you passing on the disease?

 

As far as I am aware there is no available data on this.

There is some data suggesting asymptomatic (due to their natural immune response) covid +ve people are 25-40% as infectious as people with symptoms.

 

But:

a) this is lumps together asymptomatic and 'presymptomatic' people. ( People who turn out to be 'presymptomatic' are likely to have viral load/infectiousness closer to symptomatic people, biasing these figures upwards.)

b) it doesn't take into account duration of infectiousness. (Also likely biasing these figures upwards, if asymptomatics are infectious for a much shorter period.)

 

So I think the low end of this range, or lower, is likely in practice, & these vaccines should make herd immunity much more achievable, even if uptake is partial.

[talahtnut]

At one time the UK gov. were going to limit compensation to

£120k but changed that to £0.  Do you feel lucky?

[DogNo1]

Is there any evidence to show that asymptomatic people are infectious for a shorter period of time than symptomatic people?  What of pre-symptomatic people?  Are they presumed to go on to develop symptoms and be intectious?  

In my opinion, a test to measure viral load would be useful in determining how infectious a person is.  If the vaccines were to keep most people from developing an infectious viral load, that would be quite useful.  Unfortunately we don't have that granularity of detail yet.

[Salerno]

1 hour ago, talahtnut said:

 

 

No profession is without nutters; they walk amongst us all. The group has a whole 250 members after a month, they claim not to be anti-vaxers but certainly can't claim to not be conspiracy nuts:

 

Quote

...The Times found posts saying that the Pfizer-BionTech coronavirus vaccine was a new frozen virus, similar to smallpox, to be “unleashed” on the world. They compared it to “poison”.

 

Edited December 6, 2020 by Salerno
Typo

[teacherclaire]

4 hours ago, DogNo1 said:

The various vaccine producers claim that their vaccine is X% effective.  What does "effective" mean?  

On Monday (Nov. 9), the dynamic drug company duo of Pfizer and BioNTech announced that early results from their late-stage Covid-19 vaccine clinical trial showed their jabs were 90% effective. But that statement alone opens the door for dozens more questions—which the limited data can’t answer just yet.

But to a public health organization like the US Centers for Disease Control and Prevention (CDC), efficacy and effectiveness mean two different things. “Efficacy” is what is demonstrated, to varying degrees, by a vaccine in a randomized trial like Pfizer’s. The same vaccine’s “effectiveness” is based on observational studies, once the shot is deployed in the real world. A vaccine’s effectiveness may not be the same as its efficacy.

 

Let's call it a hoax until they know the real effectiveness of their product. 

 

What does "90% effective" mean for Pfizer's Covid-19 vaccine? — Quartz (qz.com)

[AlexRich]

2 hours ago, impulse said:

 

What does "works" mean in that context?

 

I suspect it means you don’t contract Covid-19? 

[impulse]

1 hour ago, AlexRich said:

3 hours ago, impulse said:

What does "works" mean in that context?

I suspect it means you don’t contract Covid-19? 

 

Might mean that if you do catch it, you won't be symptomatic.   But still contagious.

 

[mommysboy]

12 hours ago, impulse said:

 

Might mean that if you do catch it, you won't be symptomatic.   But still contagious.

 

Yes you could be contagious but there is the old saying 'coughs and sneezes spread diseases'.  However, a very small number of people could still go on to become infectious even though they test negative on the day of travel and have been vaccinated.

 

I suppose it's about risk reduction.  From trial results so far we can say the following:

 

1.  The Oxford jab is about 60% effective at preventing all infection (which means all those people can't spread the disease).

2. The Pfizer and Moderna vaccines are 95% effective at preventing active infection.

3.  All seem to be very effective at preventing serious illness.

 

Ultimately a half decent vaccine well deployed will likely tip the balance in a country's battle against their epidemic by reducing the R rate to below 1 without the need for lockdowns, etc, by direct protection or curbing onward transmission.  I think the main point is that with mass vaccination life can go back to normal, and serious illness is greatly reduced. Fingers crossed for the Oxford jab, or the world is reliant on the Sinovac vaccine- who knows it might be the best anyway.

[talahtnut]

16 hours ago, Salerno said:

 

No profession is without nutters; they walk amongst us all. The group has a whole 250 members after a month, they claim not to be anti-vaxers but certainly can't claim to not be conspiracy nuts:

 

 

Welcome to the World Doctors Alliance.

https://worlddoctorsalliance.com/blog/dr-wodarg-and-dr-yeadon-request-a-stop-of-all-corona-vaccination-studies-call-to-sign-the-petition/

[Puccini]

On 12/6/2020 at 2:48 PM, DogNo1 said:

Given that Pfizer and Moderna have tested very few vaccine recipients, how can they make that claim?

How many did they test? The other day, I saw the number 45,000 mentioned but I don't remember for which of the two vaccines you mentioned.

[DogNo1]

Pfizer and Moderna only tested people who appeared to show symptoms.  They did not test everyone vaccinated.  Only AsrtaZeneca did.

[placeholder]

On 12/6/2020 at 8:48 PM, DogNo1 said:

Given that Pfizer and Moderna have tested very few vaccine recipients, how can they make that claim?

 

On 12/6/2020 at 8:48 PM, DogNo1 said:

Given that Pfizer and Moderna have tested very few vaccine recipients, how can they make that claim?

"Very lpw" is not a scientific term. They hsve tested 10's of thoussnds.

[placeholder]

On 12/6/2020 at 8:57 PM, kenk24 said:

Yo. Dog #1 - 

 

We live in a world of false claims and advertising as a daily affair... every dog food is going to be the best and your dog will love it... 

 

There was a dog food that used to claim - "all meat, not a speck of cereal... " to which Dave Letterman responded - 'my dog drinks from the toilet bowl, I don't think he will mind a speck of cereal.' 

 

So, the answer is that if not under oath and in a court of law, you can claim whatever you like... 

The FDA would definitely disagree.

[Thailand Forever]

On 12/6/2020 at 9:26 AM, Salerno said:

 

No profession is without nutters; they walk amongst us all. The group has a whole 250 members after a month, they claim not to be anti-vaxers but certainly can't claim to not be conspiracy nuts:

 

 

Funny how from a perspective of "knowing", others who do not subscribe to that knowledge are labelled as anti-whatever's or nutters.  I myself feel that the amount of deaths from Covid do not warrant the level of fear and panic that is ongoing.  The body has an immune system for a reason and it is doing its job.  The vaccine or whatever, may work but it will be years before all this is sorted out.  Best of luck old chap.

[Salerno]

30 minutes ago, Thailand Forever said:

I myself feel that the amount of deaths from Covid do not warrant the level of fear and panic that is ongoing.

 

Join the club; that doesn't mean there aren't a bunch of nutters polluting social media.

[1FinickyOne]

1 hour ago, placeholder said:

The FDA would definitely disagree.

And does that make them right? 

 

Is calling sugar by another name not sugar? 

[placeholder]

1 hour ago, kenk24 said:

And does that make them right? 

 

Is calling sugar by another name not sugar? 

You're the one who made the ridiculous comparison of the standards for the covid vaccine to those for dog food. Ya really think that dog food has to go through all the rigorous trials and protocols that vaccines are put through by the FDA? 

10's of thousands of dogs are fed kibble and then watched for months while their health is assessed?

Nonsense.

[NanLaew]

On 12/7/2020 at 12:26 AM, Salerno said:

On 12/6/2020 at 11:37 PM, talahtnut said:

 

 

No profession is without nutters; they walk amongst us all. The group has a whole 250 members after a month, they claim not to be anti-vaxers but certainly can't claim to not be conspiracy nuts:

 

Quote

...The Times found posts saying that the Pfizer-BionTech coronavirus vaccine was a new frozen virus, similar to smallpox, to be “unleashed” on the world. They compared it to “poison”.

 

 

Yes, these Luddites lay the blame at the feet of that awful Dr Edward Jenner FRS FRCPE, who willfully infected the eight year old son of his gardener with cowpox in the first recorded experiment in successful immunization by vaccination.

 

For them, it's been downhill ever since.

Edited December 11, 2020 by NanLaew

[placeholder]

2 hours ago, Thailand Forever said:

Funny how from a perspective of "knowing", others who do not subscribe to that knowledge are labelled as anti-whatever's or nutters.  I myself feel that the amount of deaths from Covid do not warrant the level of fear and panic that is ongoing.  The body has an immune system for a reason and it is doing its job.  The vaccine or whatever, may work but it will be years before all this is sorted out.  Best of luck old chap.

Except for the small fact that the hospitals are being forced to turn patients away or and medical workers are exhausted from overwork. So it's not just folks afflicted with covid who suffer.