Chapter XXIX: How Smallpox Is Prevented

We now come to the study of a disease, the cause of which has not been positively recognized. We know that it is very communicable; but we know also that there is absolutely no reason for anyone's ever contracting it, since there is a way by which it may easily be prevented.

[Sidenote: Fatality of smallpox before the discovery of vaccination]

Something over a hundred years ago, smallpox was one of the most fatal diseases known. It is estimated that during the eighteenth century it killed over 60,000,000 people.

Up to the time when the Spaniards invaded Mexico, there had been no smallpox there. The Spaniards brought the disease with them, and historians tell us that out of the 12,000,000 people living in Mexico at that time, at least 6,000,000 died from smallpox. At that time the disease was considered fatal throughout the world; when it broke out in a community, people fled without stopping to bury their dead. It was a rare thing to see a person not more or less disfigured by the marks the disease leaves on the face and body.

To-day we find a very different condition. There are now fewer fatalities from smallpox than from almost any other communicable disease. During 1906 and 1907 only 169 deaths from smallpox were reported from all over the United States to the Census Bureau at Washington. What has caused this marked falling off in the fatality of the disease?

[Sidenote: Discovery of vaccination]

During the time that smallpox was killing so many people, all the doctors were trying to find something that would cure the disease or that would prevent it. In the latter part of the eighteenth century Dr. Edward Jenner, an English physician, noticed that milkmaids did not have smallpox as much as did people of other occupations. He also noticed cows with little sores on their udders that looked very much like the sores that come with smallpox. He therefore tried making on the arms of people sores just like those on the udders of the cows. He did this by taking a little of the matter from the sores on the cows and putting it into the scratches on the people's arms. After these sores had healed, the people who had been thus treated did not have smallpox. This simple practice has caused one of the most deadly diseases known to man to become one of the most easily controlled.

[Sidenote: Prevention of smallpox by vaccination:]

Though it is well known that before the discovery of vaccination smallpox was a fatal disease, there are still some persons who say that vaccination has done nothing to reduce the mortality. When you learn some of the facts, you can judge for yourself whether or not vaccination does prevent smallpox.

[Sidenote: (_1_) In the Franco-Prussian War]

During the Franco-Prussian War in 1870-71, the German soldiers were all vaccinated, and only a part of the French army was vaccinated. Smallpox broke out in the two armies. As a result, 6,000 of the French died from smallpox and only 278 of the Germans. In many instances, the German and the French soldiers were confined in the same hospitals, with exactly the same opportunities to contract the disease. But, you might ask, if vaccination prevents smallpox, how did it happen that there were _any_ cases among the German soldiers? In order to prevent smallpox, vaccination must be successful; that is, it must "take." We will tell you about different kinds of vaccination a little later.

[Sidenote: (_2_) In Sweden]

In Sweden we find strong evidence that vaccination prevents smallpox. Up to 1801, before vaccination was introduced into that country, the yearly death rate from smallpox was 2,050 out of each million of the population. In 1801 vaccination was introduced into Sweden, but the people were allowed to be vaccinated or not, just as they pleased. During the ten years ending with 1811, the annual death rate from smallpox had dropped from 2,050 per million of the population to 686 per million. Later, vaccination was made compulsory (that is, everybody in Sweden was obliged to be vaccinated), and in 1894 the death rate had dropped to only two deaths a year per million population. Is it merely a coincidence that this great falling off in deaths from smallpox came after vaccination was discovered, or was it due to vaccination?

[Sidenote: (_3_) In the Philippine Islands]

Before the Philippine Islands were occupied by the Americans, vaccination was very little practiced, and a large percentage of the deaths in those islands was caused by smallpox. In 1897 smallpox caused about 40,000 deaths. A few years later the Americans enforced vaccination among the inhabitants of the Philippines, and the result was that in 1907 there were only 304 deaths from smallpox. There has been practically no quarantine for smallpox and no disinfection; the only cause of the suppression of the disease in the Philippine Islands is vaccination--nothing else.

[Sidenote: (_4_) In Gloucester, England]

In Gloucester, England, there used to be a great many people who did not believe in vaccination, though it is doubtful if they themselves could have explained why they did not. They seem to have been much like the man who, when asked, "What do you think of this?" replied, "I don't know anything about it, but I am against it." In 1890 Gloucester had a population of 42,000 people, most of whom had never been vaccinated. In the latter part of 1895, smallpox broke out. Quarantine was strictly carried out, but the disease continued to spread. As the people saw the number of victims rapidly increasing, many of them concluded that they had rather be vaccinated than have smallpox, even though they did not really believe in vaccination. By the first of April, 1896, over 36,000 people had been vaccinated in Gloucester, and by the first of August there was not a case of smallpox in the city. But what had happened in the meantime? There had been 1,979 cases of smallpox; a very large amount of money had been expended in quarantining; hundreds of persons had been disfigured for life; and 439 lives had been lost. And all this simply because the people did not believe in vaccination.

Quarantining smallpox is a most expensive luxury, which may possibly retard the progress of this disease, but was never known to check an epidemic of it. Every epidemic of smallpox during the last one hundred years has been checked by vaccination.

[Sidenote: Why some diseases do not return]

There are certain diseases which you are not likely to have more than once; one attack protects against another. Why and how does one attack of a certain disease protect against another? When a person is taken sick with one of these diseases, the cells of his body immediately begin to make a substance called antitoxin. We learned something about antitoxin when we were studying diphtheria. In diseases like scarlet fever, measles, and smallpox, in which one attack protects against another, the antitoxin that is formed in the body when you are sick stays there for a long time, in some cases as long as you live. While this antitoxin is present in the blood, the cause of the disease cannot live in the body; hence you cannot have the disease again. After some diseases this antitoxin seems to disappear from the blood in a short time; after others, it seems to remain for several years; and after still others it remains as long as you live. After diphtheria it stays in the blood only a short time, so that one may have diphtheria a second time within a few years. Some people have smallpox, measles, or scarlet fever a second time, but with most people these diseases never return.

If we knew how to make the cells of our bodies produce this antitoxin and keep it stored up in the blood all the time, we should never have any of these diseases. But in many cases we do not know how to cause the cells to manufacture this antitoxin. However, in one or two diseases we do know how to persuade them to make the antitoxin, and the one in which we know how to accomplish this best is smallpox. This is just what is done by vaccination.

[Sidenote: How vaccination prevents smallpox]

The object of vaccination is to put the cells of the body to work making antitoxin. To do this, it is necessary to get some of the toxin into the body. We want to get in just enough to make the cells work, and no more. Therefore we make a very small scratch, and put into it some of the vaccine which contains the toxin of smallpox. It is impossible to have these germs in your body and not be affected by them to some degree. If you did not feel a little sick, the cells would not be making antitoxin, for the thing that makes you sick is what makes the cells go to work. But this sickness is only a matter of a day or two, and after the cells have made the antitoxin, it will stay in your body a long time, longer in some cases than in others.

Some people, after they have once been vaccinated, can never be successfully vaccinated again; neither can such people ever have smallpox. Most people, however, can be successfully vaccinated every five to seven years, and there are a few people who will "take" if vaccinated every year or two. These conditions indicate the length of time that the antitoxin of smallpox will live in the bodies of these different persons. If vaccination, properly performed, does not take, the person is not in a condition at that time to catch smallpox; and if vaccination, properly performed, does take, it is positive evidence that if this person had been exposed to smallpox, he would have taken the disease.

[Sidenote: Necessity of repeated vaccination]

It is frequently asked, "How long will vaccination protect against smallpox?" You can no more answer this question than you can tell how long the antitoxin will live in the blood of any particular person. The only safe thing to do is to be vaccinated every few years, and if smallpox is present in your community, get vaccinated every year until the vaccination takes. If it takes, it shows that you were in a condition to catch the disease; and if it does not take, you may feel safe from smallpox for a while, at least.

=Questions.= 1. Why was smallpox formerly more widespread and
more often fatal than it is now? 2. Tell of the discovery
of vaccination. 3. Give instances to show the influence of
vaccination on smallpox epidemics. 4. Why must there be repeated
vaccinations? 5. Show how vaccinating for smallpox is like taking
antitoxin to prevent diphtheria.

=Remember.= 1. Before the introduction of vaccination, smallpox
was one of the most dangerous diseases known. 2. All evidence
of history tends to show that vaccination has caused smallpox
to become a very mild disease and a comparatively rare one. 3.
Successful vaccination repeated at proper intervals will prevent
smallpox. 4. Vaccination must be repeated because we do not know
just how long the material developed in the body from a single
vaccination will last.