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.
[Illustration: FIG. 62. In Sweden, before vaccination, smallpox
caused 2,050 deaths per million population (represented by the
large square). Since the introduction of vaccination the death rate
has dropped to 2 per million population (represented by the two
small squares).]
[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.