Correlation and causation - Page 2

[Deborah]

Well, let's look at the Germ Theory in relation to polio.

In the popular view, everybody who got polio ended up dead or paralyzed. In real life, 999 out a 1,000 people who got polio ended up just fine. And that one person could have ended up anywhere on a spectrum from minor health sequelae to dead.

So, exactly what happens when someone is exposed to bacteria or a virus? Some people get sick. Some people don't get sick. Some people get very sick. Some people die. The interactions between the human bodies and the bugs are very complex and immensely variable.

I'll say it once again. The important opportunity with the polio epidemics was figuring out why some people became really sick when they got polio and the vast majority did not. And this opportunity was missed.

The big error around the Germ Theory was acting as though everything was solved once you identified the particular bug that caused the illness.

To skip to another, related, point: the brilliant folks who fought for better living conditions and improved sanitation in the late 1800s and early 1900s saved millions of lives. Few of them understood the Germ Theory, nevertheless they managed to figure out what needed to be done to reduce the death rate and they did it. Without knowing which bug was causing which disease.

To give a concrete example: one of the major causes of infant death was diarrhea. Which is caused by a whole slew of different bugs. So going down the line and identifying the relevant bugs, one by one and developing a vaccine for each one would have been a long-drawn out, very expensive and somewhat iffy proposition. Providing running water in working class housing, regulating food handling, paying working men enough so their wives could stay home and breast feed their babies...that sort of stuff got to the core of the problem and saved huge numbers of babies from dying in infancy. Along with teaching women how to maintain some degree of cleanliness when they lived in horrendous conditions and how to care for newborns when they didn't have their mothers around to teach them (because they were emigrants) and all the other practical work achieved by the Progressive Movement in the U.S. and similar movements in other countries.

[carriebft]

edit: nvm. not worth the time.

[orangewallflower]

Originally Posted by uccomama

1. This does not mean they cause disease.

2. There are legitimate doubts that viruses actually exist.

There is really no doubt about these two things.

Again, I'm not here to argue about vaccine effectiveness, and I am intrigued by the idea that sanitation did more than vaccines to reduce disease incidence.

[Deborah]

There are a number of ways that the true story of the decline in disease is sort of distorted.

1) Concentration of attention on diseases for which there is a vaccine. In my example above I talked about the fact that many, many, many babies died of diarrhea. If you can find some actual stats on infant mortality, especially in infancy, you'll see that this was a major cause of death. So changes in living conditions, education, better diet all played a big role here, not vaccinations.

2) Crediting medical care when other factors played a huge role. I've talked before about just how bad living conditions were in big cities. True, lack of medical care played a role in some deaths, but people got sick in the first place because they were malnourished and living in unspeakable conditions. However, unless you really know your history, the story generally presented is that doctors figured out how to treat stuff better, including developing vaccines to prevent diseases and this sounds pretty good.

3) A focus on a decline in the rates of incidence of disease (some of which can be credited to vaccines) versus a decline in the death rate from disease (most of which had occurred before the vaccines became commonly used. Although, there are some illnesses where both the disease and the death rate declined before the vaccine became anywhere close to universal. See diphtheria, for an example.

4) A claim that a vaccine has accomplished something it hasn't accomplished--the easiest example is pertussis. The vaccine hasn't and will not and cannot eliminate this illness.

Sorry, this is a bit disorganized.

A good book to read (and it is a great book) on living conditions in the late 19th and early 20th century is: "The Other Half...a new biography by Tom Buk-Swienty, a Danish historian and former newspaper correspondent in the United States."

[carriebft]

But some diseases are still very prevalent in clean countries, in clean areas, in clean families-- rotavirus, nearly all of us get it. IN a few years when they do some in depth studies on rotavirus incidence since the introduction of the new vaccine, I assume we will see a great decline (we already have quite a bit of data showing that decline). Will this be because we suddenly got cleaner?

[cloak]

Originally Posted by carriebft

But some diseases are still very prevalent in clean countries, in clean areas, in clean families-- rotavirus, nearly all of us get it. IN a few years when they do some in depth studies on rotavirus incidence since the introduction of the new vaccine, I assume we will see a great decline (we already have quite a bit of data showing that decline). Will this be because we suddenly got cleaner?

Nah...It's because parents of a child with diarrhea can tell the doctor their kid got the rotavirus vax and the doctor can just rule that out with out testing to save time.


http://www.aap.org/advocacy/rightcare.htm

6. KEEP A CLEAR AND UP-TO-DATE RECORD OF IMMUNIZATIONS. This can help doctors do a better job of diagnosing a problem in an emergency. For example, if your child has a bad infection, and the doctor knows your child has been vaccinated against Hepatitis, the doctor can rule that out. This can save time.

[carmel23]

if you listen to the Larry Brilliant TED presentation, a doctor who saw the very last case of small pox in India, you will see that he never claims that vaccinations are the sole method of eliminating the virus.

He states that at the time, even if they were to vaccinate everyone in India, it would do any good because the next day there would be tons of babies born (roughly the number of people living in Canada!).

It is far more complex and sophisticated then that. And the method for developing the reported cases at the time was basically going door to door with a picture asking of anyone in the house resembled the picture. (This was before google and the internet.) When they did this, the number of reported cases increased.... when they didn't the number of reported cases decreased.

But they weren't collecting the numbers so that people could sit around arguing over the effectiveness of vaccines decades later. They were collecting them so they could see where an outbreak occurred (rapid detection) and respond and quickly as possible to create a blanket of immunity around the outbreak (rapid response). Vaccines are part of this, and to reduce the debate to if they were the sole agent in eliminating a disease or not is to not see the forest through the trees, yk?

It is really fascinating, and sheds some light on how they respond to pandemics today--things like avian flu and SARS, and yeah, h1n1.

[carmel23]

Originally Posted by uccomama

2. There are legitimate doubts that viruses actually exist.

they exist as far as anything with DNA exists:

http://derisilab.ucsf.edu/

http://www.nytimes.com/2008/10/07/he...ch/07conv.html

[carmel23]

Originally Posted by ThereseReich

Because the Germ Theory is not proof. If the Germ Theory is actually false, then the whole premise behind vaccines is wrong. I'm not sure if you've seen this thread already, but in post #9, I linked to several sources that disprove the Germ Theory: http://www.mothering.com/discussions....php?t=1135209 and I can easily get more if those weren't enough.

Who cares about Louis Pasteur? This is 100 year-old science. All the links in that thread question Pasteur... so what about DNA sequences of the viruses?

Why are we basing the discussion on 100 year-old science?

[alexsam]

(I'm not a usual in this forum, but...) I think there is a lot of evidence that many vaccines do work (like the poster that spoke about the idea that we can actually track the way that they work on a cellular and chemical level). Some people don't believe this (like, the talk of the idea that the Germ Theory is not "proven", some people don't "buy" anything about vaccines). But, by and large, scientists of pretty much every field agree that for certain diseases, vaccines do the job within an individual's body and stop or prevent a specific disease for a specific person and works for most people. Now- this conversation (especially at MDC) does not exist in a vaccume and the thing to consider as this conversation progresses is that people have individual tolerances for risk (say, I'd rather not get vaccinated for flu and take my chances with the disease than the vaccine), have concerns about other chemicals in the vaccines (heavy metals, etc.), are opposed to the forced nature of vaccines (that they are "mandatory"), etc. So, while you may get a pretty solid consensus that if you are a milkmaid who has been exposed to cowpox and so your body has learned to fight it and now you don't get smallpox, the equation with a modern vaccine and the ways in which modern vaccines impact personal and public health is much more complex and it is within this complexity that there is discourse.

I think what the overall idea to this thread is that is where the spark is coming from is the idea that in terms of mass, public health, it is not so much the vaccines than sanitation (or other factors). Some nasty diseases come from dirty water. Clean the water and the vaccines may not be necessary. So, if you clean the water and give the vaccine, how do you know which made the change?


And as for correlation and causation, it is like another poster said, being able to track to a single variable that was introduced before the change and describing the method. For your polio example, you can see that if you take individual X, vaccinate them, expose them to polio, they will not develop the disease and scientists can explain exactly how that works in the body on a chemical and cellular level. However, on a mass scale, sanitation plays a much bigger role, so if you are looking at it from a public health perspective, then the question (of if the vaccine actually did erradicate polio from the US) is totally valid because it was not a single measure (variable) that happened at that time. In the first example of the individual being vaccinated, that is a causation (single variable of the vax, exposure to disease, and how the vaccine worked can be tracked). The public health perspective is correlation as there were many variables and the whole thing cannot be explained by a single description of the process of that variable.

This is also an issue with vaccines- they have two "bodies" that are being impacted- the individual and the group. So while the course for the individual might be a "causation" scenario, the course for the group is more "correlation".

OK- back to hiding around here...

[Sileree]

Originally Posted by orangewallflower

"I am intrigued by the idea that sanitation did more than vaccines to reduce disease incidence."

You may find this interesting as an official-y source that apparently thinks so.

"In any case, the number of infections prevented by vaccines is actually quite small compared with the total number of infections prevented by other hygienic interventions, such as clean water, food, and living conditions."

http://books.nap.edu/openbook.php?re...=10306&page=44

[alexsam]

Originally Posted by carriebft

But some diseases are still very prevalent in clean countries, in clean areas, in clean families-- rotavirus, nearly all of us get it. IN a few years when they do some in depth studies on rotavirus incidence since the introduction of the new vaccine, I assume we will see a great decline (we already have quite a bit of data showing that decline). Will this be because we suddenly got cleaner?

Well- as devils advocate, there could be other factors... A handwashing campaign or a change in soap ingregients? A particularly cold or warm winter? Some other environmental or social shift?

I'm not necessarily disagreeing with you, but I'm saying that very little in large scale public health is so cut and dry.

[ema-adama]

I wrote this post yesterday before all the replies and just didn't post it - I am going to read all the new replies and think some more.... thank you for a very interesting discussion.

I am saying that I am not aware of a study that has been done that shows that vaccines, and vaccines alone, are responsible for the dramatic change in incidence of disease, particularly in the 1950's. I am aware of the use of graphs to show the incidence of disease with the date of the introduction of the vaccine coupled with the data that the vaccine produces antibodies. It seems that this is sufficient 'proof' that vaccines eradicated the disease. Which might be the case.

However, I have not seen a study that controls for access to clean water and fresh food, breastmilk for babies, clean living conditions, etc. As a PP commented with the breastfeeding example - scientists asked questions to understand how breastfeeding a baby could account for an improved IQ score - by designing studies to control for confounding variables such as education, socio-economic status etc. (for the record, I am not sure all the parameters of breastmilk and the breastfeeding relationship have yet been understood). I am not aware of a study that seeks to explain the correlation between vaccines and diminished disease in the 1950's while controlling for other environmental aspects of health other than vaccines.

There are confounding variables when it comes to health and disease. I do not think anyone would deny that exclusively breastfed babies are healthier overall than those who are partially breastfed or artificially fed. I also do not know anyone who would deny that clean water and fresh food are essential to good health. As is a daily dose of sunshine to get your vit D. But as of yet, we do not have any studies that show that vaccines are superior to clean water, wholesome nutrition, exclusively breastfeeding babies and exercise outside in the fresh air and sun.

I realise this is maybe chutzpah to ask these questions and for the most part people are very comfortable with the idea that vaccines have saved us from disease and death.

But I could not help wondering what the basis is for that understanding. And if it has been vigourously tested. And if not, why not.

It is mostly assumed that when a baby has a seriouse complication that is related in time with a vaccine that it is the vaccine as vaccines don't harm peole, they save them. But what if they do harm some people? No one knows just who would be at risk as no one is asking the questions to try to identify those babies that are at risk.

Perhaps I am not expressing myself clearly here. Essentially I am trying to understand how people accepted the idea that vaccines saved us. What is that understanding based on. How valid is that understanding? How have the confounding variables been controlled for to give us the information that it is indeed the vaccine and not something else? While at the same time I am trying to understand the reluctance to exploring whether some children are at risk for adverse reactions associated with vaccines.

[orangewallflower]

Oh, I see a little more clearly. No, no study will say that because it is preposterous. I think that you might find some interesting studies that suggest just the opposite (that of course there are many factors that affect disease rate) in the field of epidemiology. Medicine and epidemiology are interrelated, but they approach their subjects in fundamentally different ways. Don't look to a doctor to give you epidemiological information unless he has some special interest in that field. I bet, though, that you could write to an epidemiology professor whose field of study is polio and get some very interesting information on what they know about rises and falls in the disease's history.

Clinical doctors are trained to prescribe medicine. Sure, they study a lot of science, but unless they are researchers, they are not fundamentally scientists and so they might fall into the same traps that anyone would in looking at historical causality. They *should* know, however, the risks and benefits associated with anything they prescribe.

Medical research itself is mostly about clinical trials that look at how a treatment group vs. a double blind control group fare. This is very different from looking back at polio on a societal level.

[ema-adama]

I guess I am getting at what I see as a double standard. Knowing there are many variables to health, but chosing to believe that vaccines offer superior protection to other factors is just that. A choice to believe it. There is no way that anyone can say emphatically that it is the vaccine alone. I have tried to convince myself, and I usually end up at the point where general measures to protect health against bacteria and viruses seem like a more sensible approach. Can you imagine the day where we need a vaccine to create specific protection for each and every contagious disease 'out there' when it is reasonable to think that general precautions such as hand washing, wholesome nutrion and clean water might be just as effective on a public health scale?

However, when it comes to babies/children being harmed by vaccines, the fact that they are related in time is made insignificant. With no studies done on children themselves to establish if there is indeed a subgroup in the pediatric population that might be at risk. There is no attempt to answer the question scientifically - other than epidemiological studies, which by nature of their design are unable to study the children themselves.

I am still thinking about this and I might not be making sense in my thought sequences, but there seems to be a kink in the use of correlation and causation.

I am curious as to what is prepostirous orangewallflower. Can you explain a bit more?

[ema-adama]

Originally Posted by alexsam

I think what the overall idea to this thread is that is where the spark is coming from is the idea that in terms of mass, public health, it is not so much the vaccines than sanitation (or other factors). Some nasty diseases come from dirty water. Clean the water and the vaccines may not be necessary. So, if you clean the water and give the vaccine, how do you know which made the change?


And as for correlation and causation, it is like another poster said, being able to track to a single variable that was introduced before the change and describing the method. For your polio example, you can see that if you take individual X, vaccinate them, expose them to polio, they will not develop the disease and scientists can explain exactly how that works in the body on a chemical and cellular level. However, on a mass scale, sanitation plays a much bigger role, so if you are looking at it from a public health perspective, then the question (of if the vaccine actually did erradicate polio from the US) is totally valid because it was not a single measure (variable) that happened at that time. In the first example of the individual being vaccinated, that is a causation (single variable of the vax, exposure to disease, and how the vaccine worked can be tracked). The public health perspective is correlation as there were many variables and the whole thing cannot be explained by a single description of the process of that variable.

This is also an issue with vaccines- they have two "bodies" that are being impacted- the individual and the group. So while the course for the individual might be a "causation" scenario, the course for the group is more "correlation".

OK- back to hiding around here...

Thank you so much for your thoughts - it certainly has helped clarify for me why a graph and an explanation of how the vaccine works on an individual level does not mean that any change in public health can automatically be attributed to the vaccine. It just can't be with so many other variables.

Originally Posted by Deborah

Well, let's look at the Germ Theory in relation to polio.

In the popular view, everybody who got polio ended up dead or paralyzed. In real life, 999 out a 1,000 people who got polio ended up just fine. And that one person could have ended up anywhere on a spectrum from minor health sequelae to dead.

So, exactly what happens when someone is exposed to bacteria or a virus? Some people get sick. Some people don't get sick. Some people get very sick. Some people die. The interactions between the human bodies and the bugs are very complex and immensely variable.

I'll say it once again. The important opportunity with the polio epidemics was figuring out why some people became really sick when they got polio and the vast majority did not. And this opportunity was missed.

The big error around the Germ Theory was acting as though everything was solved once you identified the particular bug that caused the illness.

To skip to another, related, point: the brilliant folks who fought for better living conditions and improved sanitation in the late 1800s and early 1900s saved millions of lives. Few of them understood the Germ Theory, nevertheless they managed to figure out what needed to be done to reduce the death rate and they did it. Without knowing which bug was causing which disease.

To give a concrete example: one of the major causes of infant death was diarrhea. Which is caused by a whole slew of different bugs. So going down the line and identifying the relevant bugs, one by one and developing a vaccine for each one would have been a long-drawn out, very expensive and somewhat iffy proposition. Providing running water in working class housing, regulating food handling, paying working men enough so their wives could stay home and breast feed their babies...that sort of stuff got to the core of the problem and saved huge numbers of babies from dying in infancy. Along with teaching women how to maintain some degree of cleanliness when they lived in horrendous conditions and how to care for newborns when they didn't have their mothers around to teach them (because they were emigrants) and all the other practical work achieved by the Progressive Movement in the U.S. and similar movements in other countries.

I liked this whole post, and particularly the parts I highlighted. It really touches on the differences in how to approach developing and maintaining health.

When I started reading up about vaccines and disease I thought anyone who chose handwasing and nutrition over a vaccine must be a nutjob. I just dismissed those thoughts as lunatic. But I think there might be something more to the idea of promoting general precautions for staying healthy, not specific vaccines. Unless of course the disease is very lethal and the vaccine is effective.

And in the context of the original post, I still don't understand why vaccines alone are claimed to have single handedly brought about the decline in the disease in the 1950's. And I don't understand why no one is taking parents seriously when the parents say that they saw a temporal relationship between the vaccine and the serious injury/death of their child. I do not see the evidence for the first claim and I do not see a willingness to study what happens at a biological level with the 2nd.

[carriebft]

I would like to note that I never claimed it was vaccines alone that lead to the decline in disease. It would definitely be a mixture-- however, the mixture would be more parts "vaccine" in some cases than others. Diseases that are highly contagious, like measles, would never be eliminated with 'hand washing and nutrition" alone. You can wash your hands all you want and take lots of vit A, but if you come in contact with measles and you do not have immunity, you will almost always get the disease. Rotavirus and chicken pox are two others that will infect pretty much everyone by the time they they are older children if immunity is not present.

[Marnica]

delete

[Marnica]

Originally Posted by orangewallflower

There is really no doubt about these two things.

Again, I'm not here to argue about vaccine effectiveness, and I am intrigued by the idea that sanitation did more than vaccines to reduce disease incidence.

If there was no doubt about these things there wouldn't be a debate.....doubt exsists because there is another reality...another possibility. Whether one chooses to believe in an alternative explanation, learn more about it and then reevaluate their thinking is another story.

[Marnica]

Originally Posted by ema-adama

I still don't understand why vaccines alone are claimed to have single handedly brought about the decline in the disease in the 1950's. And I don't understand why no one is taking parents seriously when the parents say that they saw a temporal relationship between the vaccine and the serious injury/death of their child.

Really? You really don't understand this? The medical establishment is not to be questioned. Anything that brings light to an alternative/additional explanation as to why diseases declined will never be highlighted. To do so would undermine confidence in vaccines in general which are the Holy Grail of medicine. If we are led to believe that vaccines have single handedly saved us from deadly disease we will be more apt to run out and roll up our sleeves today for just about anything that they can convice us is "deadly". As for why the medical establishment is not taking parents seriously about the relationship between vaccines and adverse outcomes to me is quite obvious. It''s the same reason as above....there is far too much at stake financially, historically, morally.....if they were to find that in many mnay cases vaccines have killed, maimed and permanently disabaled, contributed to autoimmune disease etc etc in a generation of children cab you imagine the implications?? It boggles the mind. So what does the medical community do? It ignores and denies. It reminds me of the Shaggy song "It Wasn't Me"

To be a true player you have to know how to play
If she say a night, convince her say a day
Never admit to a word when she say makes a claim
And you tell her baby no way

Think about when you have caught someone in a lie...you KNOW they are lying because perhaps you saw them do something with your own eyes, but they deny it. You can't prove it because nobody else saw, but you know and the person just denies denies denies....nothing is ever resolved, all you want is the person to admit the truth, but that never happens. You still know the truth.