Today, the deadly disease typhus is largely confined to history books, eradicated in great measure by the work of Ludwik Fleck, a brilliant Jewish scientist who was imprisoned by the Nazis. Forced to experiment on prisoners in the Nazi death camp of Buchenwald, Dr. Fleck managed to invent a vaccine against typhus – and keep his world-changing discovery a secret from his brutal Nazi overlords.

Fear of Typhus and Hatred of Jews

When we look back on the Holocaust era, it’s difficult for us to appreciate the extent to which the Nazis and others feared typhus and to understand the way that terror was employed by Nazis to stoke fear and hatred of Jews. Yet the intense terror of typhus outbreaks helped to fuel the Nazis’ hatred of Jews.

Typhus epidemics raged when people lived in close proximity in unsanitary conditions and cannot change their clothes or bathe regularly. Armies were particularly prone to typhus outbreaks during wartime, when soldiers lived in squalid conditions and lice – which spread the disease – ran rampant.

Dr. Ludwik Fleck

With the rise of the Nazi movement, Jews were increasingly blamed for typhus. “The Nazis often portrayed those they persecuted as vermin, parasites, or diseases,” the United States Holocaust Museum notes. During the Nazi era, German “medical professionals repeatedly pushed the false claim that Jews were especially responsible for outbreaks of typhus…” In Nazi propaganda, Jews were commonly depicted in political cartoons as lice; the implication was that they carried diseases, particularly typhus. “Jews are lice; they cause typhus” declared a Nazi propaganda poster disseminated in Poland in 1941.

"Jews are lice; they cause typhus."

The threat of typhus, particularly, was used by Nazis as an excuse to confine Jews to ghettos in Nazi-occupied cities. Ironically, the terrible conditions in overcrowded ghettos were precisely those that allowed typhus to spread. In 1940, 380,000 Jews were imprisoned inside the Warsaw Ghetto, the largest Nazi ghetto. Over 80,000 residents eventually succumbed to starvation and disease. (Virtually all remaining Jews were deported to Nazi death camps where they were murdered.)

In 1941, SS General Reinhard Heidrich instructed the SS’s chief physician to deliberately introduce a typhus epidemic into the Warsaw Ghetto. Soon, typhus was raging through the ghetto, killing large numbers of starving, malnourished, imprisoned Jews there.

In 1941, SS General Reinhard Heidrich instructed the SS’s chief physician to deliberately introduce a typhus epidemic into the Warsaw Ghetto.

Soon after this Nazi-initiated epidemic, in October 1941, Dr. Jost Walbaum, the Chief Health Officer of the Nazi-imposed Polish government told an audience of physicians that it was necessary to imprison and murder Jews in order to stop typhus and other infectious diseases. “The Jews are overwhelmingly the carriers and disseminators of typhus infection,” he announced. “There are only two ways (to “solve” this). We sentence the Jews in the ghetto to death by hunger or we shoot them… We have one and only responsibility, that the German people are not infected and endangered by these parasites. For that, any means must be right.” These chilling words were met with applause.

Typhus, World War I, and Dr. Fleck

Typhus profoundly shaped the course of World War I. A major epidemic broke out in Serbia with the start of fighting in 1914; within a year, 150,000 people had died of typhus in Serbia, including 50,000 POWs. The mortality rate of the Serbian outbreak reached as high as 70%. A third of the doctors in Serbia died of the disease. According to the London-based Microbiology Society, the raging outbreak of typhus in the midst of World War I “dissuaded the German-Austrian command from invading Serbia in an attempt to prevent the spread of typhus within their borders.”

At the same time, typhus began spreading throughout the Russian army on the war’s eastern front. After the Russian Revolution in 1917, Russia’s typhus epidemic raged out of control. History and science writer Arthur Allen documented the incredible story of Dr. Fleck and the race to invent the vaccine against typhus in his 2014 book The Fantastic Laboratory of Dr. Weigl: How Two Brave Scientists Battled Typhus and Sabotaged the Nazis (Norton and Co.). In a 2015 interview, he described the terrible toll that typhus took at the time. "Following World War I, when there was this terrible chaos all over the Eastern Front after Lenin pulled his troops from the Eastern Front, and Russian soldiers were roaming through all parts of Russia – what’s now Russia, Ukraine, Belarus – and there were POWs in Poland. And the disease just spread like wildfire through that entire region. There have been estimates of as many as 20 million cases of typhus and...3, 4, 5 million deaths…”

One of the many soldiers fighting on the German side of the war who watched typhus’ spread with horror during World War I was Ludwik Fleck, a young Jewish medical student from Lvov, which was then part of the Austro-Hungarian Empire (in 1919 it became part of a newly-independent Poland; today, it is part of Ukraine). Lvov was home to a thriving Jewish population when Dr. Fleck was born in 1896. He attended medical school, but his studies were interrupted by World War I, during which Dr. Fleck worked as a medical officer and witnessed first-hand the terrible toll that typhus took on soldiers and civilians alike.

During World War I, Dr. Fleck came into contact with Dr. Rudolf Weigl, an older and acclaimed biologist. Shocked by the horrific effects of typhus he witnessed in the military, Dr. Weigl began working on a vaccine against typhus, building on research that was being done throughout the Austro-Hungarian Empire at the time. Dr. Weigl collaborated with other scientists, including his wife Zofia, and managed to produce an effective vaccine against typhus in a laboratory setting, using lice as the hosts of the disease. The vaccine worked, but it was extremely difficult to produce and Dr. Weigl resisted experimenting on humans.

As the acclaimed Polish microbiologist Stefan Krynski has noted, typhus vaccine production in the years before World War II was extremely limited. Dr. Weigel’s “hesitation before introducing for use in humans was based on extreme caution, enhanced by the fact that he himself was not a doctor of medicine…” Dr. Weigl’s early typhus vaccines degraded quickly, but he established a research lab in Lvov and recruited prominent scientists – many of them Jews – to help research typhus and other diseases.

At the time, it was difficult for Jews to obtain research positions in Polish universities. Dr. Fleck, by now a prominent virologist in his own right, was one of many talented Jewish scientists who was unable to obtain an academic appointment. Instead, Dr. Fleck established a private medical lab in Lvov where he analyzed several diseases, including typhus. His work brought him into contact with Dr. Weigl and his team, one of the local scientific labs which didn’t discriminate against Jewish researchers. In Dr. Weigl’s lab, Dr. Fleck made a major breakthrough, inventing a skin test to diagnose typhus.

Rising Hatred of Jews

While the Nazis consolidated power in Germany in the 1930s, Poland’s right-wing nationalist government fomented anti-Semitism and passed anti-Jewish laws inside Poland, too. Under Prime Minister Felicjan Slawoj-Skladkowski, who served as Poland’s prime minister and minister of the interior from 1936 to 1939, Poles were encouraged to boycott Jewish businesses and even to riot against Jews in various Polish towns.

Jewish butcher shops were forced to shut, Jewish businesses found it difficult to receive commercial licenses or bank loans. Prime Minister Slawoj-Skadkowski encouraged boycotts of Jewish businesses and professionals. In Polish universities, students were forced to sit in special sections of the classroom. Polish rioters attacked Jews in towns including Radom, Brest-Litvost, Vilna, Czestochowa, and Lvov, Dr. Fleck’s home town. The authorities refused to intervene, instead arresting members of Jewish self-defense groups, not Polish rioters.

Arthur Allen describes the atmosphere in Lvov’s medical school: by 1937, no new Jews were being admitted to the school. “Members of anti-Semitic student clubs...menaced the remaining Jewish students in the streets and the halls of the university, armed with razor blades slotted into wooden sticks. Of the many Jewish students beaten and attacked, at least three died…”

Dr. Rudolph Weigl

Many Poles refused to give into this atmosphere of hate, including Dr. Fleck’s mentor Dr. Rudolf Weigl. One day when Dr. Weigl walked into the lecture hall where he taught in the Lvov medical school, he saw all his Jewish students standing, forbidden to sit. “What’s going on here?” asked Dr. Weigl. When anti-Jewish students explained that Jews were forbidden to sit in the class, Dr. Weigl replied, “In that case, I will stand until they sit.” (Quoted in The Fantastic Laboratory of Dr. Weigl: How Two Brave Scientists Battled Typhus and Sabotaged the Nazis by Arthur Allen.)

Creating a Vaccine inside the Lvov Ghetto

Nazi forces entered Lvov on June 29, 1941. Jews were forced to give up their property and herded into a cramped ghetto. Approximately 5,000 Jews were shot by Nazis during the establishment of the Lvov Ghetto. Over 110,000 Jews were soon imprisoned behind the ghetto’s walls. Starvation and disease – including typhus – were rampant.

Liquidation of the Lvov Ghetto,

Dr. Ludwik Fleck, along with his wife Ernestyna and his son Ryszard were forced into an apartment in the Lvov Ghetto with two other Jewish families. For several months, Dr. Fleck managed to keep up his research inside the ghetto. Along with three fellow Jewish scientists – a Dr. Olga Elser, a Dr. Bernard Umschweif and a third scientist whom Dr. Fleck identified as Dr. Anhalt – he miraculously managed to create a typhus vaccine in laboratory conditions inside the Ghetto’s “Jewish Hospital”. Their survival was largely due to Dr. Rudolf Weigl, who listed these Jewish scientists as associates in his lab, which was now working for the German Army.

After the Holocaust, Dr. Fleck described the research he carried out in the Lvov Ghetto: “It was of major importance to work out such a method that would allow us to produce the vaccine in the primitive conditions of the ghetto…I managed to create the typhus vaccine made from the urine of the patients (in the Jewish Hospital) suffering from the typhus fever. The vaccine saved lives of many people in the ghetto as well as (nearby) Janowska Concentration Camp, where we vaccinated the prisoners....”

Dr. Ludwik Fleck

The incredible success of Dr. Fleck’s typhus vaccine didn’t go unnoticed by the Nazi guards. They asked Dr. Fleck if it were possible to inoculate Germans too. “I answered that it was doubtful, as they were of different race and the vaccine had been made from the urine of ill Jews…” Dr. Fleck recalled telling them.

In March and April 1942, the Nazis murdered 15,000 Jews who’d lived in the Lvov Ghetto. They were sent to the Janowska concentration camp, and from there were sent by trains to the Nazi death camp Belzec. Among the thousands of murdered Jews were Dr. Fleck’s two sisters, Antonia Fleck-Silber and Henryka Fleck-Kessler. Both women had been teachers in the Vocational School for Jewish Girls in Lvov. They were murdered, along with their husbands, in Janowska.

Vaccine Miracle in Buchenwald

Dr. Fleck, his wife and son, were deported to Auschwitz. At first Dr. Fleck was forced to do backbreaking slave labor, but soon the camp officials recognized Dr. Fleck’s medical expertise and sent him to Auschwitz’s infirmary to help conduct medical experiments related to bacteria and infection on prisoners. At the end of 1943, Dr. Fleck was sent to the Buchenwald concentration camp. There, the German government was trying to set up a laboratory to invent a durable typhus vaccine that could be mass produced and shipped to German soldiers.

The leader of this project was a German quack scientist named Joachim Mrugowsky who’d faked much of his research and was, as Dr. Fleck would later describe, “scientifically illiterate”. After his lab in Berlin was destroyed by British bombers, author Arthur Allen describes, Mrugowsky “decided to produce the vaccine at Buchenwald, thinking that allied bombs would not fall there. Jewish inmates of the concentration camp – those whom the Nazis condemned to death as mere human lice – would be employed to manufacture it, thereby saving the German troops at the front.”

At the time, the best-known typhus vaccine was that produced by Dr. Rudolf Weigl. However, Dr. Weigl’s method incubated typhus in the bodies of lice. With their overwhelming fear of lice, there was no way the Nazis would allow researchers to breed lice in Buchenwald. An entirely new way of making typhus vaccines would have to be invented. Dr. Mrugowsky recruited another German scientist named Dr. Erwin Ding-Schuler to assemble a typhus vaccine lab in Buchenwald. Dr. Ding-Schuler went about choosing Jewish scientists from among Buchenwald’s inmates to staff his prison lab. Many of the men he selected weren’t actually scientists or medical doctors, but were pretending they had medical expertise as a way to appear useful to the Nazis and stay alive.

The team worked round the clock and invented a novel new way to breed typhus in animals that weren’t normally used in this type of typhus research. Dr. Ding-Schuler’s research methods involved using guinea pigs, rabbits and mice. Just before Christmas in 1943, the vaccine was ready: Dr. Ding-Schuler injected prisoners with the vaccine and waited for the results.

Tragically, the typhus vaccine didn’t work. Dr. Ding-Schuler falsified the experiment records to make it look as if he’d done what no one else had achieved: develop an effective typhus vaccine that could be used outside of a lab and which didn’t involve breeding lice. Yet he needed help in finding what had gone wrong.

Dr. Fleck managed to create a life-saving typhus vaccine, working with Jewish slaves as his colleagues in the unimaginable hell that was Buchenwald.

It was then that Dr. Ludwik Fleck was transferred to Buchenwald, and Ding-Schuler placed him in charge of the vaccine project. Right away, Dr. Fleck realized that Dr. Ding-Schuler had no idea what he was doing. Privately, Dr. Fleck called him a dummkopf, Yiddish for idiot. Dr. Fleck later recalled that the Nazi scientists at Buchenwald “looked into their microscopes and continuously misunderstood what they saw… There was no individual author of the error. The error grew out of the collective atmosphere.”

Dr. Fleck adjusted the method that typhus was being bred and managed to create a life-saving typhus vaccine, working with Jewish slaves as his colleagues in the unimaginable hell that was Buchenwald.

Duping the Nazis

Once Dr. Fleck adjusted the vaccine production method, he and his fellow Jewish scientists decided to keep their discovery secret. Dr. Eugen Kogon, a Jewish scientist imprisoned in Buchenwald who led the Jewish team producing the vaccine, later described what happened. “Since Ding-Schuler demanded large quantities of vaccine, we produced two types: one that had no value and was perfectly harmless, and went to the front; and a second type, in very small quantities, that was very efficacious and used in special cases like for comrades who worked in difficult places in the camp.” (Quoted in The Fantastic Laboratory of Dr. Weigl: How Two Brave Scientists Battled Typhus and Sabotaged the Nazis by Arthur Allen.)

"We were consciously producing a non-active vaccine… Ding, the idiot, never wised it up…”

Whenever the Nazis became suspicious and demanded vaccines to test, Dr. Fleck and the other Jewish scientists would send a vial of the precious real vaccine, and independent tests would confirm that the vaccine worked. Dr. Fleck later recalled that Dr. Ding-Schuler’s “lack of knowledge of science was very useful in the sabotage activities that were soon undertaken by a group of doctors and scientists from the Concentration Camp Buchenwald… We were consciously producing a non-active vaccine… Ding, the idiot, never wised it up…”

While Dr. Fleck and others produced small quantities of vaccine using rabbits, guinea pigs and other animals, Dr. Rudolf Weigl continued to manufacture vaccines derived from lice in his laboratory in Lvov. Dr. Weigl was also determined to trick the Nazis and help Jews.

Dr. Weigl was compelled to turn almost all of his vaccine over to the Nazis, but author Arthur Allen has documented that Dr. Weigl was allowed to keep 8,200 doses each month in order to conduct further experiments and inoculate family members and friends. Instead of honoring this arrangement, Dr. Weigl acted heroically. He sabotaged the vaccine doses he gave to the Nazis, and donated the doses he was allowed to keep to resistant groups, orphans, Jewish fighters and priests. He even managed to smuggle 30,000 precious doses of vaccine to the Warsaw Ghetto, where typhus was rife, to inoculate 30,000 Jews there.

Testifying to Nazi Atrocities

After he was liberated, Dr. Ludwik Fleck testified about the horrors he’d witnessed. “When it comes to the reprehensible experiments carried out on prisoners, I had an opportunity to give testimony on that matter in the Nuremberg Court,” Dr. Fleck later recalled. Among the many gruesome medical “treatments,” experiments and tortures he described, was the deliberate infection of large numbers of prisoners with typhus, so they could then be given the vaccine.

At the Nuremberg trials, Dr. Joachim Mrugowsky, who set up the typhus project in Buchenwald, was found guilty of crimes against humanity and was hanged. Dr. Ding-Schuler killed himself in an American military prison before his trial. He left a letter asking Dr. Kogon, the Jewish director of vaccine trials in Buchenwald, to look after his wife and children. Yet Dr. Ding-Schuler’s wife soon died – from typhus.

In Postwar Poland, Dr. Rudolf Weigl was accused – wrongly – of having been a Nazi informer. He was largely ignored by the Polish scientific establishment and died in 1957, his great heroism and scientific brilliance all but forgotten. In 2003, Yad Vashem declared Dr. Weigl “Righteous Among the Nations” and planted a tree in his honor in the Avenue of the Righteous in Jerusalem.

In 1957, Poland experienced a resurgence of anti-Semitism, and the Flecks fled, joining their son in Israel.

Dr. Fleck survived the Holocaust, along with his wife and son. Their son, Ryszard Fleck, moved to Israel with the establishment of the Jewish state in 1948. Dr. Fleck and his wife stayed in Poland, where Dr. Fleck held distinguished posts in the University of Lublin and University of Warsaw, conducting research and writing philosophical works. In 1957, Poland experienced a resurgence of anti-Semitism, and the Flecks fled, joining their son in Israel.

In Israel Dr. Fleck worked in epidemiology in the Institute of Biological Research in the Israeli town of Nes Ziona. He continued to write philosophical works. Dr. Fleck’s last paper was written in Israel, titled “Crisis in Science: Towards a Free and More Human Science.”

Dr. Ludwik Fleck died in 1961 and is remembered today most of all for his work as a scientific philosopher, not his groundbreaking discovery of a vaccine for typhus. The Stanford Encyclopedia of Philosophy notes that Dr. Fleck was one of the most influential philosophers of science of the modern age. His groundbreaking discovery of a typhus vaccine, and his insistence on using it to help his fellow imprisoned Jews, laid the foundation for a lifetime of scientific research and contemplation of the role of humanity and morality in science.