Catching a killer

Humans have always been looking for ways to protect themselves against killer infectious diseases, with the first documented ‘vaccination’ dating back to the year 1000. The son of a Chinese statesman was said to have received a variolation by blowing pulverized smallpox scabs up his nose. Variolation was the first immunization technique developed, which uses infectious material (such as pus) from smallpox infected patients. This infectious material is then scratched into the skin of the patient. By giving small doses of the disease, it becomes possible to give the patient a mild form of it, while their immune system is boosted up. This procedure was first introduced in Europe and America in the 18th century; however, it had been in use for much longer. Slaves arriving in America were already variolated against smallpox, indicating that this natural technique of protecting oneself against a deadly disease is much older still.

Variolation, as it was practiced during the smallpox epidemics of the 18th century, was a very risky procedure as the patients actually developed a mild version of the disease which could develop into the full blown form. This also meant they were contagious for people who were not yet immune. So the variolated patients were placed in quarantine until they were deemed to be no longer infectious (usually three weeks).

Immunology and epidemiology (the study of patterns, occurrence, etc. in diseases) go hand in hand. One of the first epidemiological studies on variolation was performed in 1721 in Boston. This study proved that there was a mortality rate of 14% amongst people who naturally contracted the disease, compared to only 2% for people who had been inoculated. During these smallpox epidemics, the first mass vaccination campaigns in history were conducted.

Unlike variolation, vaccination uses inactivated viruses. In the case of the first vaccines against smallpox, a different but highly similar disease was used, making vaccination much safer than variolation. The first real vaccine was administered in 1796 by Edward Jenner. The famous story goes as follows, Jenner noticed that a dairymaid infected with a much milder form of smallpox, called cowpox, did not in fact develop smallpox. He then vaccinated a young boy with the cowpox. Several days later he injected the boy with smallpox and saw that he did not develop the disease. This is known as the first successful vaccination in history.

Not only is smallpox the disease that formed the basis for the first immunization, it is also the first disease to have a major worldwide vaccination campaign and the first (and so far only) disease to be eradicated. Therefore the most important moment in vaccination history is the eradication of smallpox in 1979. The great success of this programme formed the basis for the world health organization’s ‘Expanded Programme on Immunization’ (EPI). This programme aims to protect children form a very young age against preventable infectious diseases. The programme has been hailed as a major success, with 80% of children protected through vaccination by 1990. In 2014, the WHO found that 86% of children worldwide were vaccinated against type 3 polio.

Even though lots of progress has been made in the last century, a lot of work is still to be done. A large number of children remains unvaccinated and at risk for preventable diseases. As mentioned before, smallpox is the only eradicated disease so far. Other diseases, such as polio, are on the verge of elimination, but a last push is needed to achieve this. Commitment from governments and people together is necessary in order to eliminate other infectious diseases.

Gwendoline Deslyper