The Current

How the polio epidemic revolutionized modern medicine

In the early twentieth century, a diagnosis of polio could mean almost certain death. By 1952, the epidemic had devastated countries in Europe and baffled medical professionals. In her book, The Autumn Ghost, Dr. Hannah Wunsch explores how Danish doctors revolutionized their practice in the midst of this tragedy.

A new book explores how the spread of this devastating disease led to the creation of the ventilator

A doctor with blue gloves holds a ventilator mask to a patients face.
Modern ventilation in medical care has a surprising origin story in Denmark. (Nathan Denette/The Canadian Press)

Read transcribed audio

The year was 1949 and polio was raging across the United States. 

By 1952, the epidemic had spread around the world, and Copenhagen, Denmark, was feeling the toll as autumn began. More than 3,000 people were admitted to hospital, and patients were wheezing and gasping for breath. Some were paralyzed.

The doctors and nurses there could do very little to help.

On the left is a book cover that shows two doctors. The male doctor is at a desk, and the female doctor is checking up on a patient. There is white and yellow text overlay that is the book's title and author's name. On the right is a headshot photo of the author who is wearing a gray blazer and she is smiling at the camera.
The Autumn Ghost is a book by Hannah Wunsch. (Greystone Books)

"For the unlucky few, and it was usually less than about five per cent of those who got the disease, they would develop paralysis — the virus would actually go to the nerves of the spinal cord and cause weakness of limbs," Dr. Hannah Wunsch told The Current host Matt Galloway.

"If you were really unlucky, [you had] a weakness of the muscles of respiration, and if you were truly unlucky, the muscles that control things like swallowing, which was called bulbar polio."

Wunsch is a critical-care physician and researcher at Sunnybrook Health Sciences Centre in Toronto. Her book, The Autumn Ghost: How the Battle Against a Polio Epidemic Revolutionized Modern Medical Care, explores how polio in Denmark forced medical professionals to rethink critical care. 

"There was this epidemic in Copenhagen, which was really the moment in time when they figured out how to provide what's called 'positive pressure ventilation' — modern ventilation to patients who had polio," Wunsch said.

"This really was the impetus for the development of modern intensive care.... So, as an intensive-care physician, I was really interested in it because it's really my origin story for my specialty."

Patient care

In her book, Wunsch traces how the devastating effects of the polio epidemic would create the impetus for modern ventilation systems. Ventilators, which allow patients with respiratory trouble to breathe, were crucial medical equipment during the height of the COVID-19 pandemic. 

There was about a 90 per cent mortality, so they were up against a wall- Dr. Hannah

"We take for granted that these things exist: intensive-care units, mechanical ventilators, all the gadgets and things we can do to people," she said. "There was a time before that, and that's why this epidemic is special, because it was that turning point."

Before the polio vaccine was created in 1955, treatment for severe polio cases was only available through the use of an iron lung — a large respirator that encloses most of the patient's body and helps to stimulate breathing during paralysis. During the peak of the crisis, Copenhagen only had one iron lung.

But even with all the iron lungs in the world, the machines would not prove useful. 

"They were admitting towards the end of August about 50 patients a day, and many of them had bulbar polio — they had already seen dozens of deaths," Wunsch said. "They also knew that even if they had iron lungs, bulbar polio was not really helped by iron lungs.... There was about a 90 per cent mortality, so they were up against a wall."

Finding solutions

In this moment of crisis, anesthesiologist Dr. Bjørn Aage Ibsen had an idea. 

"He was an incredibly smart man and perceptive," Wunsch said. "[He] was the one who really proposed this breakthrough in care that came about, which was the idea that rather than trying to suck the lungs open, why not push air into the lungs the way they often did for patients in the operating room?"

A black and white photograph that depicts a polio ward in the 20th century.
Polio wards were lined not only with beds, but with iron lungs, large metal ventilators that helped patients to breathe during the worst of the infection. Some survivors never regained lung function and spent the rest of their lives in the devices. (U.S. Food and Drug Administration)
Ibsen would apply the same tactics used in surgery to care for patients suffering from respiratory failure.

"He was just very experienced with keeping people alive in the operating room, and that was because he would give them general anesthesia, he'd paralyze them, and then he'd have to breathe for them," Wunsch said.

"The main problem for these polio patients [was] they just weren't breathing well enough, and that if he could both 'protect the airway,' meaning not allow those secretions in the back of the throat to get into the lungs, and also allow them to breathe ... that this would potentially solve the problem."

Vivi Ebert, a 12-year-old girl with bulbar polio, would be the first patient to undergo this procedure. 

"He took over her care and he demonstrated after a kind of a rocky start that he could, by blowing air, kind of hand ventilating her, keep her alive, as he did with people in the operating room, and so this was pretty kind of miraculous." Wunsch said. 

But, without the benefit of mechanical ventilators at the time, it wouldn't be feasible to have doctors ventilating the patient 24 hours a day. Ibsen would enlist medical students at the University of Copenhagen to hand ventilate all day and all night.

"They had six eight-hour shifts with a 10-minute break each hour for cigarettes, and they had really no end in sight.... They did this for weeks and then months as they realized that this worked, they were keeping people alive," Wunsch said.

"It's an exciting story in that it's about people coming together in a city."


Oliver Thompson is a writer, producer and musician. Originally from the UK, where he worked for the BBC, Oliver moved to Canada in 2018.

Interview produced by Alison Masemann.