# Effect of the vaccines



## SGWidow (11 Jan 2021)

Probably very, very basic questions - but here goes

When someone get vaccinated...….

1. He can still get Covid?
2. He just won't get ill?
3. He will be asymptomatic?
4. He is still contagious?

Does this mean that when the population is 50% vaccinated that there will be a whole pile of contagious people merrily walking around and potentially and unknowingly infecting others?


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## Purple (11 Jan 2021)

SGWidow said:


> Probably very, very basic questions - but here goes
> 
> When someone get vaccinated...….
> 
> ...


1. He can still get Covid?_ In theory he can._
2. He just won't get ill? _There is a much lower change that he will get ill_
3. He will be asymptomatic? _Most likely_
4. He is still contagious? _Much less so._

Does this mean that when the population is 50% vaccinated that there will be a whole pile of contagious people merrily walking around and potentially and unknowingly infecting others?
The purpose of the vaccine and other restrictions is to get the R number well below 1.
Children under the age of 10 don't need to get vaccinated. They are half as likely to get the virus and if they do they are half as likely to pass it on. Therefore their R number is one quarter that of adults. 
Those between 10 and 18 probably shouldn't get vaccinated either. They are generally more susceptible to side effects from vaccines and their statistical chance of becoming very ill of dying is almost zero. Since they are generally asymptomatic they are less likely to infect other people.
Those in high risk groups who cannot take the vaccine should continue to self isolate even as the vaccination levels reach 50% of the population. 

Therefore if we have vaccinated 50% of the population we will be well on the way to ending this as a public health emergency.


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## Brendan Burgess (11 Jan 2021)

Hi SG

Good questions. I caught the end of a guy on BBC Radio 4 this morning dealing with some of these issues.

It wasn't clear to me (and him?)  whether the vaccine
1) Prevented the person from becoming infected and infectious
or
2) It just prevented them from becoming sick after becoming infected.

I think that the research shows that the person probably does not become infected and therefore does not become infectious.

It might be the same for a natural infection.  Does that prevent the person from becoming infected again or does it just prevent them from being sick?

The expert concluded that natural infection would not result in herd immunity but that vaccination of enough people probably would.

Brendan


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## Purple (11 Jan 2021)

How long will vaccine immunity last?
[broken link removed]


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## SGWidow (11 Jan 2021)

Thanks for the reply, Purple - and apologies Brendan, just saw your post when finished mine!!

Here's the, perhaps mistaken, background to the question.

I heard more than one public health expert explain that the reason that NH residents are being given priority is because they are the most vulnerable and thereby most susceptible to getting seriously ill and that whilst the vaccine prevents serious illness, it does not prevent transmission.

If, the explanation continued, the vaccine prevented people from spreading the virus, there would be an argument for telling the cocooners to continue cocooning and transfer the priority to the "real economy", the "out and about" folk!

I can find one of these clips (probably) if necessary....


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## Brendan Burgess (11 Jan 2021)

Pfizer-BioNTech COVID-19 Vaccine Frequently Asked Questions
					

Frequently asked questions on the emergency use authorization of the Pfizer-BioNTech COVID-19 Vaccine




					www.fda.gov


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## SGWidow (11 Jan 2021)

Thanks Brendan,

So. for the avoidance of doubt, the answer to the initial question of

4. He is still contagious?...……..is not "much less so" as our esteemed colleague said but more like "it is hoped that this is the case, based on the experience with other vaccines, but we don't know yet."

Given this, my original central question, repeated below, still holds. What's curious is that I have heard very little commentary on this and I have been listening to a lot of radio over the last week or so.

Does this mean that when the population is 50% vaccinated that there will be a whole pile of contagious people merrily walking around and potentially and unknowingly infecting others?


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## Purple (11 Jan 2021)

SGWidow said:


> 4. He is still contagious?...……..is not "much less so" as our esteemed colleague said but more like "it is hoped that this is the case, based on the experience with other vaccines, but we don't know yet."


Based on all previous vaccines, particularly those for respiratory illnesses, that answer is "much less so".
As this is a new disease we won't know yet but there's no reason to believe that it will be any different. The the various vaccines effectiveness is well over 90% it is more likely to be the case. 
That doesn't mean vaccinated people shouldn't continue to observe guidelines; even if you carry the virus internally it could still be on your hands or clothes and you could pass it on that way.


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## Ceist Beag (11 Jan 2021)

SGWidow said:


> Does this mean that when the population is 50% vaccinated that there will be a whole pile of contagious people merrily walking around and potentially and unknowingly infecting others?


There is a flaw in the logic of your question. The advice remains that people should continue to exercise social distancing, mask wearing, hand washing, etc.
In order for (unvaccinated presumably) people to be at risk of infection from the vaccinated people you describe, they would have to be putting themselves at risk of infection.


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## SGWidow (11 Jan 2021)

I respectfully disagree with the last two posts.


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## Brendan Burgess (11 Jan 2021)

That really is the key point - people should not rely on herd immunity or on other people getting the vaccine.

They should get it themselves. 

Until you get the vaccine, you should treat everyone else as a source of infection and keep your distance.

Brendan


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## Cricketer (11 Jan 2021)

Purple said:


> 4. He is still contagious? _Much less so._





Purple said:


> Children under the age of 10 don't need to get vaccinated. They are half as likely to get the virus and if they do they are half as likely to pass it on. Therefore their R number is one quarter that of adults.





Purple said:


> Since they are generally asymptomatic they are less likely to infect other people.



These are important claims. Can you provide a source for them?


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## Purple (11 Jan 2021)

Cricketer said:


> These are important claims. Can you provide a source for them?


I posted this in another thread in relation to children.
This report from Nature discusses rates of infection from asymptomatic carriers.


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## Cricketer (11 Jan 2021)

Purple said:


> I posted this in another thread in relation to children.
> This report from Nature discusses rates of infection from asymptomatic carriers.


Thanks, that's interesting. I'm very struck by your certainty in relation to all of this.


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## Purple (11 Jan 2021)

Cricketer said:


> Thanks, that's interesting. I'm very struck by your certainty in relation to all of this.


I just look at the available facts and form views based on what I consider to be the balance of probability. There's enough emotion and fear out there. The median mortality age is in the mid 80's and 93% of those who have died had preexisting conditions.


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## Paul O Mahoney (11 Jan 2021)

SGWidow said:


> I respectfully disagree with the last two posts.


Vaccines do not eliminate viruses they simply suppress them while protecting the individual of suffering from the effects of having the virus.

The virus remains albeit with less ways of spreading and causing health issues including death.
If you are vaccinated successfully and come in contact with someone who is carrying the virus they might still pass on the virus but your immune system will not allow the virus to make you sick.

Vaccinated people passing on the virus is largely unknown now. 

Fauci in the USA believes that we might need an immunity level as high as 80% .

More data will help solve these conundrums but thats going to take a long time.


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## Cricketer (11 Jan 2021)

Purple said:


> I just look at the available facts and form views based on what I consider to be the balance of probability. There's enough emotion and fear out there. The median mortality age is in the mid 80's and 93% of those who have died had preexisting conditions.


I agree, but of course it's not really about your or my risk of dying from the virus. It's about the risk of so many people presenting at hospitals that - bad enough the vulnerable should die prematurely - but that those who are next in line could also be at risk. The reality is that altruistic behaviour in that regard can and does happen, but behavioural science tells us that real behaviour change happens when people are fearful.


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## Purple (11 Jan 2021)

Cricketer said:


> I agree, but of course it's not really about your or my risk of dying from the virus. It's about the risk of so many people presenting at hospitals that - bad enough the vulnerable should die prematurely - but that those who are next in line could also be at risk. The reality is that altruistic behaviour in that regard can and does happen, but behavioural science tells us that real behaviour change happens when people are fearful.


Indeed; people are reasonable and logical, the mob is stupid and emotional.
We should do what we can and do what we should to protect those around us but we should try to avoid surrendering to fear and emotion. They are the enemy of reason.


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## SGWidow (11 Jan 2021)

Paul O Mahoney said:


> Vaccinated people passing on the virus is largely unknown now.



Thanks Paul

This is not what the notice that Brendan posted said.

It is also not the mindset that was adopted when formulating public policy regarding the vaccine rollout.

Here's what Professor Karina Butler had to say - the relevant bit starts just after 3 minutes.

Certain posters seem to disagree with the good professor's circumspection - maybe they know more than her?

Today with Claire Byrne (rte.ie)


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## Cricketer (11 Jan 2021)

SGWidow said:


> Certain posters seem to disagree with the good professor's circumspection


That's why I was said I was struck by Purple's certainty. I haven't read or heard anything definitive re. the level of transmission from vaccinated persons.


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## Purple (11 Jan 2021)

Cricketer said:


> That's why I was said I was struck by Purple's certainty. I haven't read or heard anything definitive re. the level of transmission from vaccinated persons.


It's not certainty, it's an opinion based on what I consider to be the probability, given the available facts.


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## Paul O Mahoney (11 Jan 2021)

SGWidow said:


> Thanks Paul
> 
> This is not what the notice that Brendan posted said.
> 
> ...


But bear in mind having people vaccinated is the proper way of defeating the virus.  

We might be discussing the fact that vaccinated people don't pass it on, these things are unknown for so many varied reasons that science will have to try and find the answer.

Add in the variants its really a "fluid" situation.


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## SGWidow (11 Jan 2021)

Cricketer said:


> That's why I was said I was struck by Purple's certainty. I haven't read or heard anything definitive re. the level of transmission from vaccinated persons.



I hear ya!


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## Purple (11 Jan 2021)

SGWidow said:


> Here's what Professor Karina Butler had to say - the relevant bit starts just after 3 minutes.
> 
> Certain posters seem to disagree with the good professor's circumspection - maybe they know more than her?


Where did I say that there was evidence that the Covid19 vaccines blocked transmission?

I said that vaccines generally reduce transmission and that those who are asymptomatic are less likely to transmit the disease.

The purpose of the vaccine, and other public health measures, is to reduce the R number and so the rate of infection within the general population. As the vaccine is rolled out other measures can be relaxed as and when the R number is reduced.

What Professor Butler said is that we do not yet know if the vaccines reduce transmittibility and therefore we cannot base our public health strategy on such an assumption.
She said that they hope that the vaccines do reduce transmission and pointed out that the early animal studies support such a possibility as the viral load in the nose is reduced among those who are vaccinated but were still exposed to the virus. In other words there is an expectation of such but that's not enough to build a plan around.
I'm not making those decisions so I base my opinion on probability and the probability is that these vaccines will have an effect on transmission similar to just about every other vaccine for a respiratory illness.


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## Paul O Mahoney (11 Jan 2021)

Purple said:


> The purpose of the vaccine, and other public health measures, is to reduce the R number and so the rate of infection within the general population. As the vaccine is rolled out other measures can be relaxed as and when the R number is reduced


This for me is the "holy grail" right now, if this can be achieved with both the vaccine and good practices by the general public it would be a great achievement. 

Historically vaccines would prevent spreading but this is a new virus and we are using new technology along with proven methods to fight it.

And every single one of these vaccines are being used on an emergency level, getting full licences will be a far more difficult process and some of the unknowns will have to be known .


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## Paul O Mahoney (13 Jan 2021)

Below is something I came across tried linking but didn't work. 
It would appear that there are some initial studies going on in Israel as it has the largest amount of vaccines rolled out.

*"Does the Vaccine Protect Against Infection?*
In an ongoing study, “Maccabi health services” and KSM research center, studied the first 430,000 people who were vaccinated at their nation-wide vaccination centers.
They checked the group’s infection rates in the first few days since receiving the first dose, and then checked infection rates within the group 13 days after the first dose was given. The researchers found that on the 13th day, infection rates drop by 60% compared to those in the early days after the vaccine was given.
A second ongoing study is being conducted by “Klalit health services” and its research center. In this study, 400,000 participants were tested — half of which received the first dose of the Pfizer vaccine, while the other half didn’t get a vaccine at all.
The first 5–12 days had no effect in terms of protection. The researchers saw a similar rate of infection between the two groups. However, in this study, day 13 saw a slight change while day 14 brought a drop of 33% in infections for the vaccinated group compared to their unvaccinated counterparts.
*What Does That Mean?*
Most importantly, this is the first indication that the vaccine prevents infection and not only symptoms, even if only to a certain extent.
While the first few days after receiving the first dose seem to have no effect at all; The studies mark the 13–14 days as the tipping point in which the body creates a certain level of protection against the virus.
A 60% drop in infections compared to the early days after the first dose, and a 33% drop in infections compared to a group that wasn’t vaccinated at all is an optimistic prospect. And yet, it is important to note that some of the participants were infected even after the 13-day mark.
“These are initial indicators but they are certainly uplifting,” says Prof. Ran Balicer head of Klalit research. _“_and yet, the first dose doesn't give full protection in any case. People who received the first dose would still need to wear a mask and maintain social distancing.”


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## Purple (13 Jan 2021)

Given the current high rates of infection we need to get the R number down significantly below 1 before we consider lighting any of the current restrictions. If it is down to 0.5 the infection rate will drop quickly but given the 14 day (minimum) lag between a lockdown and the resultant reduction in infection rates we have to wait another week or so to find out what impact the current level 5 restrictions have had. 
Once the vaccine is rolled out we will have to wait another 14 days plus to see what impact that is having.


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