GU-Journal 1–2021

Page 22

Focus

Vaccines have rescued us before – What strikes me is the terrible difference in the number of fatalities. In the 17th and 18th century, epidemics and famines could result in almost 10 percent of the population dying. Fortunately, we have not been anywhere near that figure in modern times, medical historian Daniel Larsson explains. Even though there are unpleasant exceptions, the history of vaccination is on the whole a success story, says Daniel Larsson. – That certain diseases are contagious has been known for a long time, even if we did not understand how. But before the smallpox vaccine, there was no other protection than quarantine. As early as in biblical times, there are descriptions of how people with leprosy had to live in isolation from other people. But the word quarantine, which means 40 days, originated in 15th-century Venice, where ships were not permitted to enter port until, after 40 days in isolation, they could show that they were not bringing the Plague. But it was only with the smallpox vaccine that we got real protection against contagious diseases, Daniel Larsson explains. – But there is an interesting prehistory to the smallpox vaccine. As early as the 16th century, doctors in China had learned that you could take infectious agents from a patient with a mild smallpox infection and give them to a healthy person through a scratch on the skin, for example. This way, the healthy person got, hopefully, a mild variant of smallpox. The method came to Europe in the 18th

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GUJOURNAL MARCH 2021

century and was called inoculation or variolation. For example, the physician to the Swedish king Charles XII is said to have learned the method in Turkey. Daniel Larsson A prominent proponent of variolation in Sweden was Nils Rosén, who performed the procedure on Gustav III. But its use soon fell out of favour and was replaced by a better method.

– The physician Edward Jenner, active in the English countryside in the 18th century, heard that milkmaids did not get smallpox if they had already had cowpox, a harmless viral infection from cows. In 1796, he decided to test whether this was true by using variolation to give his gardener’s young son cowpox. Some time later he gave the boy smallpox using the same method. When the boy remained healthy, Jenner realized that the boy had become immune, and thus the first vaccine was invented. Smallpox used to be a terrifying disease that reemerged every 5–6 years. In principle, everyone who had not previously had the disease became infected, which meant that it was perceived as a childhood disease, says Daniel Larsson. – But in 1816, when the smallpox vaccination became mandatory in Sweden, the disease had already mutated and become less fatal, the reason for this is not really known. Smallpox is, thus far, the only disease that infects humans that has been eradicated. Malaria was also rampant in Sweden and did not die out until the 19th century,

when wetlands began to be dug out for agricultural use. At the time, another fatal disease had begun to spread in Europe instead: cholera. The disease came to Sweden in 1834 and subsequently reemerged numerous times. The disease was so serious that special cholera hospitals and cholera cemeteries were established. – There were two competing views concerning what caused cholera: People who believed that small invisible infectious pathogens caused the disease advocated quarantine, while people who believed that the disease was due to poor hygiene, demanded investment in water and sewage systems and better housing.

It was the German physician Robert Koch, who in 1883, discovered that cholera was caused by the bacterium, Vibrio cholerae. Viruses, which are 100 to 1,000 times smaller than bacteria, were discovered much later. It was not until 1939, that the researchers Gustav Adolf Kausche, Edgar Pfankuch and Helmut Ruska were able to see viruses under an electron microscope. It is through church records and burial registers that Daniel Larsson has gained insight into what diseases people died of in the past. – But it is not all that easy to know what was really behind symptoms such as coughs and fevers. Although diseases were of course serious in the past, there were also other serious health threats. During the period 1771–1772, the crops failed and about 100,000 Swedes died of starvation and starvation-related diseases. That is, of course, a huge figure, especially considering that the population was only about 1.5 million.


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