Those who grew up in the early 20th century did so not only in the shadow of famine, war and genocide – but also of rampant, ruthless, constant epidemics.

Smallpox, cholera, yellow fever, influenza, sleeping sickness and malaria alternated – or overlapped – in a chaos of death and confusion. And just when World War I was finally about to release its iron grip on the continent, the world was instead paralyzed by the Spanish flu, history’s most devastating pandemic after the Great Depression. The number of infected is estimated at 500 million, of which one tenth is estimated to have died – compared with the more than two million who died of covid-19 at the time of writing.

These epidemics were by definition limited to specific geographical areas, which relatively rarely included Sweden. But the world situation still had a profound effect on the researcher and bacteriologist Sven Gard, who was born in 1905 and thus was able to follow the seemingly endless global health crises during his studies at Karolinska Institutet. In particular, his interest in virology was aroused by a pandemic that not only reached Sweden, but is even suspected to originate from here: polio. This terrifying and highly contagious disease, also known as polio, had admittedly existed since ancient times. But the new variant that would spread panic around the world was first identified in Umeå and Stockholm at the end of the 19th century. Soon the pandemic became a fact – in some parts of the world even a kind of primitive lockdowns were introduced to slow down the spread of the then so enigmatic disease.

But the efforts were never sufficient, and the progress of the police remained relentless. As recently as 1953, more than 70 years after the first identified cases, Sweden was hit by its largest outbreak ever, with 5,000 infected. And if it were not for Sven Gard, we might have had even darker years ahead of us.

Gard, at this time professor of viral research at KI, was rarely well suited to lead the Swedish fight against polio. Earlier in his career, he had worked in New York with Nobel laureate Max Theiler, who invented the vaccine against yellow fever. Together they had researched mouse polio – a project Sven Gard continued with after he had returned to Sweden.

When general vaccination against polio was introduced in Sweden in 1957, it was remarkably a Swedish vaccine – which Sven Gard was involved in developing – that was used, not the more well-known American variants developed by Jonas Salk and Albert Sabin. Admittedly, both Salks and the Swedish vaccine were “inactivated”, which means that they – unlike “live” vaccines – did not contain viruses that could still multiply. But Gard himself considered that Salk had made misjudgments in his work, and that the Swedish vaccine was thus a safer variant. (As Erik Lycke, professor emeritus and Gard’s former doctoral student, pointed out, the Swedes were right when a failed round of Salk vaccine led to more than 200 American children suffering from polio in 1955.)

In any case, the Swedish vaccination program was a great success. By 1963, the number of reported cases of polio had been reduced to 0. Since 1977 – when a girl whose parents opposed vaccination fell ill – no one in the country has been infected with the disease.

Sven Gard’s own career was crowned with a seat on the Nobel Committee, and as a speaker at several Nobel ceremonies over the years. When it was mentioned that he himself would be awarded a Nobel Prize

however, he is said to have refused – despite the fact that he was one of the reasons why one of the heaviest shadows that rested on humanity could finally be lifted.