Very interesting, thanks! I covered some similar ground in my essay “Draining the swamp;” I think you would enjoy the references in that one. Some thoughts:
Did “medicine” cause the mortality decline?
There is a lot of truth in the McKinlay paper. In particular, it’s true that sanitation efforts probably did more than anything else to improve mortality in the 20th century. I think this is for two reasons: (1) Those techniques are less technologically advanced, and so they arrived first; vaccines and antibiotics that arrived later only get credit for mopping up what was left. (2) Prevention is more effective than cure.
But I think you have to be careful with how you interpret the data. It would be a little too easy to conclude that only certain techniques really mattered and others were not so important, and I think this is the wrong way to look at it.
One key thing to understand is that each disease spreads in its own way. Some are water-borne, some spread via insects or food, etc. This means that a given technique for prevention will work against some diseases and not others. No one technique works against all diseases; we need a collection of techniques.
For instance, you point to the amazing effectiveness of water sanitation. This is correct—against water-borne diseases such as typhoid fever or cholera. But water sanitation doesn’t help with malaria, or for that matter with covid.
Were vaccines relevant to mortality improvements?
This is tricky. First, there is the point I made above that vaccines often came after some simpler technique. But also, two of the biggest successes of vaccines are smallpox and polio.
Looking only at the 20th century (as the McKinlays do, and as is pretty common, especially since this is the period that has the best data) excludes the contributions of the smallpox vaccine, and even earlier the technique of inoculation, both of which date from the 1700s! These were big contributors to mortality declines in the 18th & 19th century.
Polio only had about a 10% fatality rate, but the rest of its victims were paralyzed for life. Looking only at mortality underweights the DALYs lost to polio.
Measles: this is an odd case. Mortality declined a lot in the early 20th century before the vaccine, but case load did not. That is, just as many people were getting measles, but the fatality rate was declining (unclear why, maybe Vitamin A or some other nutrition issue). The case rate only declined after the vaccine. So again there is a lot of relief-of-suffering that is not being counted here.
Typhoid: yeah, this is water sanitation
Influenza/pneumonia: they appear to have attributed the 1918 epidemic deaths to influenza. However, a lot of these deaths were actually caused by secondary pneumonia, which an antibiotic would have been very helpful against. Also the influenza chart here is hard to find a trend on, because of the epidemic.
Diphtheria: I don’t know why they label “toxoid” on the chart, because the first effective treatment for diphtheria was blood serum, and that was available from the 1890s.
Polio: that high number in 1910 seems to be from a particularly bad epidemic in 1916. If you look at this chart from OWID, it looks like cases were climbing, and deaths were at least not decreasing, until the vaccine came along in 1955. And again, the cases that did not die were generally paralyzed for life in one or more limbs.
Did we need the germ theory?
My reading of the history is that the germ theory was somewhat more important than you make it out to be in this piece.
On water sanitation, it’s true that these efforts began pre-germ theory, based on aesthetics and vague associations between filth/smell and disease. However, these efforts could only go so far unguided by theory. And sometimes they backfired: guided by the miasma theory, Chadwick built sewers that dumped tons of filthy water into the Thames, actually polluting the drinking water (see The Ghost Map). The germ theory helped set targets for water sanitation: they could actually count bacteria in water samples under the microscope. And I don’t think chlorination would have been introduced without germ theory. (Not checking references on this paragraph so I might be getting a few things wrong though)
Pest control is a similar example. Many efforts were begun as early as 18th or even 17th c., but, for instance, malaria and yellow fever were not eliminated until after the exact species of mosquito was discovered for each and its lifecycle and breeding habits carefully studied. Needed science for that one.
Food sanitation also was motivated by an understanding of germ theory. That’s part of how we got the FDA, etc.
Overall, some important progress on mortality was made pre–germ theory, but a lot (I think most) was made after, and I think there’s a reason for that.
I think the war on cancer will be the same. There is some progress we can make, and have already made, without a fundamental understanding of the disease, and of course we should go ahead and do that. But that will plateau at some point without a breakthrough in basic research. After such a breakthrough I would expect progress to accelerate dramatically.
Your point on the proper, theory-led goals of water sanitation is interesting. I think there’s maybe a decent way for us to figure this out.
The copy of Turneaure and Russel’s water sanitation textbook I used was from around 1940. But the first edition of that was from 1901. If we could find some analogous top-tier sources utilized just before some insights from germ theory we could probably figure out how much of the best-practices in planning changed from before/after the pervasion of the theory.
Do you think that would be fair or did I miss something? Because I’d believe you very well might be right. What I wrote was a fair representation of my sources but this is an area where I am very aware that my sources are few. So I don’t hold these beliefs nearly as confidently as my views related to something like physics in the early 1900s where my reading has been far more exhaustive.
That would be an interesting mini-research project. Also one of us could check my references here and see what I was relying on when I made those statements…
Very interesting, thanks! I covered some similar ground in my essay “Draining the swamp;” I think you would enjoy the references in that one. Some thoughts:
Did “medicine” cause the mortality decline?
There is a lot of truth in the McKinlay paper. In particular, it’s true that sanitation efforts probably did more than anything else to improve mortality in the 20th century. I think this is for two reasons: (1) Those techniques are less technologically advanced, and so they arrived first; vaccines and antibiotics that arrived later only get credit for mopping up what was left. (2) Prevention is more effective than cure.
But I think you have to be careful with how you interpret the data. It would be a little too easy to conclude that only certain techniques really mattered and others were not so important, and I think this is the wrong way to look at it.
One key thing to understand is that each disease spreads in its own way. Some are water-borne, some spread via insects or food, etc. This means that a given technique for prevention will work against some diseases and not others. No one technique works against all diseases; we need a collection of techniques.
For instance, you point to the amazing effectiveness of water sanitation. This is correct—against water-borne diseases such as typhoid fever or cholera. But water sanitation doesn’t help with malaria, or for that matter with covid.
Were vaccines relevant to mortality improvements?
This is tricky. First, there is the point I made above that vaccines often came after some simpler technique. But also, two of the biggest successes of vaccines are smallpox and polio.
Looking only at the 20th century (as the McKinlays do, and as is pretty common, especially since this is the period that has the best data) excludes the contributions of the smallpox vaccine, and even earlier the technique of inoculation, both of which date from the 1700s! These were big contributors to mortality declines in the 18th & 19th century.
Polio only had about a 10% fatality rate, but the rest of its victims were paralyzed for life. Looking only at mortality underweights the DALYs lost to polio.
More here.
Comments on specific charts from McKinlay
Measles: this is an odd case. Mortality declined a lot in the early 20th century before the vaccine, but case load did not. That is, just as many people were getting measles, but the fatality rate was declining (unclear why, maybe Vitamin A or some other nutrition issue). The case rate only declined after the vaccine. So again there is a lot of relief-of-suffering that is not being counted here.
Typhoid: yeah, this is water sanitation
Influenza/pneumonia: they appear to have attributed the 1918 epidemic deaths to influenza. However, a lot of these deaths were actually caused by secondary pneumonia, which an antibiotic would have been very helpful against. Also the influenza chart here is hard to find a trend on, because of the epidemic.
Diphtheria: I don’t know why they label “toxoid” on the chart, because the first effective treatment for diphtheria was blood serum, and that was available from the 1890s.
Polio: that high number in 1910 seems to be from a particularly bad epidemic in 1916. If you look at this chart from OWID, it looks like cases were climbing, and deaths were at least not decreasing, until the vaccine came along in 1955. And again, the cases that did not die were generally paralyzed for life in one or more limbs.
Did we need the germ theory?
My reading of the history is that the germ theory was somewhat more important than you make it out to be in this piece.
On water sanitation, it’s true that these efforts began pre-germ theory, based on aesthetics and vague associations between filth/smell and disease. However, these efforts could only go so far unguided by theory. And sometimes they backfired: guided by the miasma theory, Chadwick built sewers that dumped tons of filthy water into the Thames, actually polluting the drinking water (see The Ghost Map). The germ theory helped set targets for water sanitation: they could actually count bacteria in water samples under the microscope. And I don’t think chlorination would have been introduced without germ theory. (Not checking references on this paragraph so I might be getting a few things wrong though)
Pest control is a similar example. Many efforts were begun as early as 18th or even 17th c., but, for instance, malaria and yellow fever were not eliminated until after the exact species of mosquito was discovered for each and its lifecycle and breeding habits carefully studied. Needed science for that one.
Food sanitation also was motivated by an understanding of germ theory. That’s part of how we got the FDA, etc.
Overall, some important progress on mortality was made pre–germ theory, but a lot (I think most) was made after, and I think there’s a reason for that.
I think the war on cancer will be the same. There is some progress we can make, and have already made, without a fundamental understanding of the disease, and of course we should go ahead and do that. But that will plateau at some point without a breakthrough in basic research. After such a breakthrough I would expect progress to accelerate dramatically.
Your point on the proper, theory-led goals of water sanitation is interesting. I think there’s maybe a decent way for us to figure this out.
The copy of Turneaure and Russel’s water sanitation textbook I used was from around 1940. But the first edition of that was from 1901. If we could find some analogous top-tier sources utilized just before some insights from germ theory we could probably figure out how much of the best-practices in planning changed from before/after the pervasion of the theory.
Do you think that would be fair or did I miss something? Because I’d believe you very well might be right. What I wrote was a fair representation of my sources but this is an area where I am very aware that my sources are few. So I don’t hold these beliefs nearly as confidently as my views related to something like physics in the early 1900s where my reading has been far more exhaustive.
That would be an interesting mini-research project. Also one of us could check my references here and see what I was relying on when I made those statements…