Another herd immunity thread - Page 3

[tmaue]

Originally Posted by carriebft

where is the evidence of the iffy measles protection? you mean from people who have been neither immunized or exposed?

The main place you can find evidence is when you study the outbreaks that have occured. Those who have been vaccinated do get the disease.

But really shouldn't the burden of proof be on the vaccine and the statement that vaccines are lifelong protection. Shouldn't they be showing us that that is the case, especially when we see outbreaks in vaccinated communities, instead of them just saying they are believed to be life long.

[shuttlt]

Originally Posted by carriebft

I meant agreement in the so-called 'provaccination' camp-- ie, those in science and medicine who speak openly for vaccination. There seems to actually be an understanding that not all vaccines work for herd immunity there, but they use the herd immunity argument to sell vaccines to the masses.

Yes. You may well be right. There's probably a debate in the 'why' of it, but if my own initial ignorance is anything to go by, such details are definately not being made sufficiently clear.

[carriebft]

Originally Posted by tmaue

The main place you can find evidence is when you study the outbreaks that have occured. Those who have been vaccinated do get the disease.

But really shouldn't the burden of proof be on the vaccine and the statement that vaccines are lifelong protection. Shouldn't they be showing us that that is the case, especially when we see outbreaks in vaccinated communities, instead of them just saying they are believed to be life long.

Those who are partially vaccinated and those who are not vaccinated at all get the disease in high numbers during outbreaks (see switzerland, germany, poland, hungary, UK and USA in the past 5 years). Those who are fully vaccinated get the disease at much much lower rates, but this is because, even if we take the BEST MMR immunity numbers, only 99% will react to the vaccine and have immunity.

I believe the outbreaks do demonstrate that the vaccine gives lasting immunity.

[shuttlt]

Originally Posted by tmaue

The main place you can find evidence is when you study the outbreaks that have occured. Those who have been vaccinated do get the disease.

I had always assumed that, if true, this was because most people are vaccinated. We'd need some numbers to be sure.

Originally Posted by tmaue

But really shouldn't the burden of proof be on the vaccine and the statement that vaccines are lifelong protection. Shouldn't they be showing us that that is the case, especially when we see outbreaks in vaccinated communities, instead of them just saying they are believed to be life long.

OK. That turns it again into a dispute about the truth of particular facts coming from particular sources of authority. I'll go away and try to find where the lifelong immunity claim comes from. I assume there is a study somewhere, though whether it is large enough to satisfy people is another question. If anybody knows and would like to save me the effort I would very much appreciate it.

[shuttlt]

Originally Posted by carriebft

Those who are partially vaccinated and those who are not vaccinated at all get the disease in high numbers during outbreaks (see switzerland, germany, poland, hungary, UK and USA in the past 5 years). Those who are fully vaccinated get the disease at much much lower rates, but this is because, even if we take the BEST MMR immunity numbers, only 99% will react to the vaccine and have immunity.

I believe the outbreaks do demonstrate that the vaccine gives lasting immunity.

I would have thought if you knew the ages of the people infected and whether or not the were vaccinated you could infer back the ongoing level of protection.

[PaigeC]

Originally Posted by carriebft

Those who are partially vaccinated and those who are not vaccinated at all get the disease in high numbers during outbreaks (see switzerland, germany, poland, hungary, UK and USA in the past 5 years). Those who are fully vaccinated get the disease at much much lower rates, but this is because, even if we take the BEST MMR immunity numbers, only 99% will react to the vaccine and have immunity.

I believe the outbreaks do demonstrate that the vaccine gives lasting immunity.

I have to disagree: http://aje.oxfordjournals.org/cgi/co...ract/129/1/173

Also, remember that most unvaxed folks were probably thrilled to get measles! I know I would have been

[carriebft]

I have studies here showing 15 year immunity and I think one with 20 year immunity. I'll get them for you. All of them find the vaccine to be lasting. the 15 year study, for example, found lasting immunity at 15 years.


You can't get much better than a 30 year study since we aren't really going to have too many numbers beyond that given the date the vaccine first was used and the age the participants would be.

You aren't going to get a study that says "we looked at 1000 people at birth and their death" since the vaccine came in to play in the 60s or something.

[carriebft]

Originally Posted by PaigeC

I have to disagree: http://aje.oxfordjournals.org/cgi/co...ract/129/1/173

Also, remember that most unvaxed folks were probably thrilled to get measles! I know I would have been

I don't think that case says what you think it does.

First, we already know the measles vaccine does not work well if given prior to 12 months. And those students probably only had one dose given the years.

[carriebft]

In fact, given that those kids in that case probably only had 1 vaccine, the fact that 3.6% of them got the measles is spot on. 1 vaccine will leave about that many unprotected.

[tmaue]

Originally Posted by shuttlt

I really had the impression that a significant people believed herd immunity didn't happened and in any case vaccines don't work.

Just wanted to share my opinion on this. From what I said earlier, I believe that herd immunity could likely be achieved vaccines if EVERYONE vaccinated around the same time, not just young kids. But, I also do not believe vaccines work to provide what we consider immunity.

I believe that they can stop a good number from getting the disease (I am mainly speaking live viruses right now since that is easier for me to talk about), but I do not believe it is due to antibodies. I believe there is something else going on in the body. I believe those who have the best response to the vaccines are those who have actually have an adverse reaction such as getting a mild case of the disease.

When you see cases where people have been documented to have large antibody levels and they still come down with the disease, you know something else is going on. Also there are people who do not have antibodies, but when exposed do not get it. Everything else I believe is just my theory, so I won't go into that here.

So its kind of hard when someone asks whether vaccines work or not, because I believe they can work, but not for the reasons that they say. Kind of a trick question.

[carriebft]

10 year immunity study:
http://www.medscape.com/viewarticle/553459

15 year immunity study:
http://www.ncbi.nlm.nih.gov/pubmed/1934235

I have more but you will have to give me time to go through my links

[tmaue]

Originally Posted by carriebft

In fact, given that those kids in that case probably only had 1 vaccine, the fact that 3.6% of them got the measles is spot on. 1 vaccine will leave about that many unprotected.

It also reminds us that those of us from my generation have not had booster shots and therefore the so called herd is even more at risk, especially this many years later.

[carriebft]

Originally Posted by shuttlt

Yes. You may well be right. There's probably a debate in the 'why' of it, but if my own initial ignorance is anything to go by, such details are definately not being made sufficiently clear.

I agree; you don't necessary see "get a tetanus vaccine, protect others" kind of propaganda (though there are ones like that for pertussis, which is unproven at best but more likely does not contribute to herd immunity at all) but they way they frame it all, people come to think that all vaccines protect besides themselves.

[PaigeC]

I think this might come back to a disagreement about the definition of immunity again.

If we define immunity as "Immunity is a medical term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion." then 30 years after MMR vaccination a person would be able to avoid infection with measles. I believe that with transmission and sub-clinical illness this is definitely not the case. I know we had another thread with links to articles along this line, I can see if I can find it.

Of course, some define immunity (or maybe just success of vaccination) as reducing the severity of the illness. I personally do not.

[shuttlt]

Originally Posted by tmaue

Just wanted to share my opinion on this. From what I said earlier, I believe that herd immunity could likely be achieved vaccines if EVERYONE vaccinated around the same time, not just young kids. But, I also do not believe vaccines work to provide what we consider immunity.

This assumes that immunity from vaccines fades significantly over time. At least in the case of measles this seems to be disputed.

Originally Posted by tmaue

I believe that they can stop a good number from getting the disease (I am mainly speaking live viruses right now since that is easier for me to talk about), but I do not believe it is due to antibodies. I believe there is something else going on in the body. I believe those who have the best response to the vaccines are those who have actually have an adverse reaction such as getting a mild case of the disease.

OK. This is probably a more fundamental disagreement than herd immunity. Do you have a specific scientific reason for doubting antbodies, or are you coming from the perspective of an alternative medical paradigm e.g. homeopathy?

[ema-adama]

William Hamer, Ronald Ross, and other public health specialists in the early twentieth century developed refined mathematical models, factoring into their equations the variables involved in determining the interactions of disease agents, human hosts, and environmental conditions.

http://www.enotes.com/public-health-...-herd-immunity
I immedietly wanted to know what their variables were, and I have not got a clear answer. Anyone who knows, please pass it on (I do not like math that much, but I am interested in the theory)

At its simplest, epidemic theory considers three variables: agent, host, and environment. Each of these has many components, however—host-agent interactions vary greatly, and variations in environmental conditions influence the interactions in innumerable ways.

I am not sure if they are factoring in clean water, fresh mineral rich food, clean but not disinfected living environment, sewage systems, unpolluted air, etc. These do affect the interaction. It is just not patent-able.

The probability that an infectious agent will encounter a susceptible host while the agent remains viable is a critically important variable in epidemic theory. In constructing mathematical models of epidemics, all possible variations in all these aspects of the agent's behavior in relation to that of the host and the environment must be taken into account.

What makes a susceptible host?

Immunity may be temporary, long-lasting, even permanent. One has to consider both individual hosts and the population as a whole, known in this context as the "herd."

This is in relation to passive immunity from the placenta and breastmilk, as well as vaccination. Here the assumption is that vaccination confers life long immunity (all vaccines it would seem), thus protecting the individual and the 'herd'.

When a population has a level of lifelong immunity to a certain disease such that an epidemic of that disease cannot occur, the population is said to have herd immunity.

Each vaccine it would seem has a different percentage rate for providing life long immunity (factoring in whether it prevents transmission or only the clinical disease). I have by no means reached a final conclusion as to which vaccines actually do and do not have the potential to confer life long immunity, if any at all. But it seems to me that it was assumed that vaccines create life long immunity. End of story! (oooops, we forgot to mention shifting epidemiology, serotype replacement and the difference between Th1 and Th1 immune systems and that the disease is not actually that bad when you are well nourished and have access to clean water and living environment)

[shuttlt]

Originally Posted by ema-adama

I am not sure if they are factoring in clean water, fresh mineral rich food, clean but not disinfected living environment, sewage systems, unpolluted air, etc. These do affect the interaction. It is just not patent-able.

Surely all of these things effect whether or not you get new outbreaks of the disease (well maybe not the polluted air), and maybe how bad you are likely to get it, rather than the possibility of herd immunity?

Originally Posted by ema-adama

What makes a susceptible host?

I assume from previous posts, it means 'not immune'. Anyone disagree?

Originally Posted by ema-adama

This is in relation to passive immunity from the placenta and breastmilk, as well as vaccination. Here the assumption is that vaccination confers life long immunity (all vaccines it would seem), thus protecting the individual and the 'herd'.

I think the lifelong immunity claim is only made for live virus vaccination.

Originally Posted by ema-adama

Each vaccine it would seem has a different percentage rate for providing life long immunity (factoring in whether it prevents transmission or only the clinical disease). I have by no means reached a final conclusion as to which vaccines actually do and do not have the potential to confer life long immunity, if any at all.

I'm curious what your reasons are for doubting that vaccines can confer immunity at all, or that the lifelong claim isn't true. Why wouldn't it be?

Originally Posted by ema-adama

But it seems to me that it was assumed that vaccines create life long immunity. End of story!

There were some links to studies posted last night that I still need to read. The source of the lifelong immunity claim is important as so many people seem to doubt it.

Originally Posted by ema-adama

(oooops, we forgot to mention shifting epidemiology, serotype replacement and the difference between Th1 and Th1 immune systems and that the disease is not actually that bad when you are well nourished and have access to clean water and living environment)

Shifting epidemiology is surely an argument for not having a sloppy vaccination program, rather than an argument about whether herd immunity is achievable, or meaningful. As for serotype/Th1 immune systems, I would need to read more in order to comment.

A lot of what you say strikes me as sensible. Vaccination most certainly isn't a substitute for clean drinking water. Having said that, are there figures for how bad these diseases (say measles) are in countries that do have clean drinking water etc...?

[shuttlt]

Originally Posted by carriebft

10 year immunity study:
http://www.medscape.com/viewarticle/553459

15 year immunity study:
http://www.ncbi.nlm.nih.gov/pubmed/1934235

I have more but you will have to give me time to go through my links

OK. I've had a look at the studies you posted. I'm confused again about what the definition of immune is. Does only getting a subclinical infection count as immune. Are you sufficiently unlikely to infect anybody if you have a subclinical infection that it counts towards the herd immunity argument.

Also, the 10 year study said the following:

Projected antibody levels for kindergarten group estimated continued decrease in titers and increase in potentially susceptible population to 33% by 20 years post-MMR2 and seronegative population to 1% by 30 years post-MMR2.

Perhaps this is not a whole lot different to what happens to your immunity from catching measles for real? In any case, the drop off does strike me as significant if you need 90%+ immunity in your population.

I couldn't work out how to get the the full text of the 15 year one, so can't really comment on it. Perhaps it indicated a slower drop off in immunity?

[carriebft]

The 15 year study seemed to me to say that the projections we thought would happen did not hold and that the MMR continued to be effective. I know I have a 25 year one but I just cannot locate it at the moment.

Some also see a subclincal infection (having been exposed to wild type measles) acts as a natural booster to the vaccine. I don't see subclincal measles as much of an issue and I don't think it happens too often to the point where transmission is possible (or we would have a lot more measles cases and a lot more vaccinated measles cases-- as the case would have to have a high enough viral load to transmit, in which case it would not be too subclincal anymore)

I also think the outbreaks recently demonstrated that the MMR doesn't seem to wane or be waning yet (again, its only been around 40 years). If you look at switzerland and USA particularly, the infection remained isolated to unvaccinated and partially vaccinated populations.

[tmaue]

Originally Posted by carriebft

I also think the outbreaks recently demonstrated that the MMR doesn't seem to wane or be waning yet (again, its only been around 40 years). If you look at switzerland and USA particularly, the infection remained isolated to unvaccinated and partially vaccinated populations.

I was thinking about this last night and it occured to me that it is very possible that many of the cases that occured in these outbreaks could have very well been intentional. Many parents who do not vaccinate are not scared of their children getting measles and mumps and will go as far as having parties to get kids infected like with chickenpox. So, I was wondering how many, if any, of the kids who are affected in these outbreaks are intentional. You definetly don't hear from the reports but it would be interesting to know. This would definetly change things a bit, I would think.

One of the questions given above was about why I doubt antibodies, as far as vaccine protection goes. The reason I doubt antibodies is because you see over and over in studies and personal accounts where someone had sufficient antibody levels and still got the disease. You also get the reverse, where someone does not have antibodies and when exposed does not get the disease. There is something else that must be going on in the immune system to make this possible. They are starting to learn more but more info is needed. So, in my opinion, vaccine antibody level alone providing protection is just theory.

Then you have someone like myself who has NEVER had the flu or a flu like illness regardless of taking care of a household of sick people. What is it about me that allows me to avoid these sicknesses? Obviously it is not antibodies because they would have had to come from somewhere. I just feel they are really missing some key info on the immune system to explain some of these things.

As far as antibodies dropping off overtime, I personally feel that they are supposed to drop off naturally over time, whether from a vaccine or from natural disease. I don't believe this leaves a person susceptible because once the person encounters that disease again, the body just ramps up at that time. I think having high antibodies sitting around all the time may not be a good thing (possible problems with molecular mimicry and who knows what else).

The ramping up your body does after encountering a disease is more than just antibodies, in the case of natural immunity. But with vaccines, do you get anything else besides antibody levels raising. I believe the only real way to know if someone is immune to something is if they are exposed and do not get the illness.

Another thing I was thinking of last night was about the vaccine studies where they are measuring antibodies and using that to measure efficacy. I was wondering if they had ever taken the time to monitor the virus itself inside the body (again, I am only speaking live virus vaccines here). If they tested all children given the vaccine to see if they had the measles virus at different intervals after vaccinated to see if any of them ended up with chronic measles. I think this would be nice info to have.

I started thinking about this after seeing some info on other live vaccines that have failed, like the AIDS one, where they actually do test for the virus. They were saying with these that the vaccines can actually increase susceptibility as far as having a chronic case of the virus. Wondering if they ever looked into this for the live vaccines they give kids. If anyone comes across any studies looking at this for the live vaccines kids get, I would be interested in seeing that. Here is the info I saw that talked about the problem with some live virus vaccines which got me wondering:

http://www.sciencedirect.com/science...9e8807a161330f