|
Sabin and Salk
While the large-scale clinical trial with Salk vaccine went ahead in
1954, Albert Sabin continued developing his live-virus vaccine. Like
many researchers of the day, Sabin strongly disagreed with Salk’s
approach of using injected, “killed” virus. He believed
that long-term immunity could only be achieved with a live, attenuated—or
weakened—virus.
In the race to develop a safe and effective polio vaccine, accidents
occurred with both types. In 1955, for instance, insufficiently killed
virus in the vaccine from Cutter Laboratories in Berkeley, California,
infected some 200 children; many were paralyzed and several died. But
the global end to polio transmission would have been inconceivable
without both the “killed” (Salk) and “live” (Sabin)
vaccines. Neither Jonas Salk nor Albert Sabin patented their vaccines;
they donated the rights as gifts to humanity. |
Left: Family with fifteen children lined up for oral
polio vaccine, around 1963
Right: Albert Sabin of the University of Cincinnati feeding oral polio vaccine
to a child, early 1960s Courtesy of University of Cincinnati,
Cincinnati Medical Heritage Center,
Hauck Center for the Albert B. Sabin Archives
|
The Sabin Vaccine
An important feature of Sabin’s oral polio vaccine was that immediately
after vaccination, people shed weakened virus in their fecal waste. This
boosted immunity for others in the community and gradually reduced the
number of people susceptible to poliomyelitis.
Between 1963 and 1999, Sabin live vaccine largely replaced Salk killed
vaccine everywhere in the world. However, because the live virus in
the vaccine occasionally became strong enough to cause actual disease,
Salk killed-type vaccine has replaced the live type in the United States. |
“I have studied the effects of our new
lots of polio vaccine in 100 adult volunteers and during the next few
days shall give it to my wife and 2 children as well as to our neighbors
and their children.”
—Albert Sabin, 1957 |
Sabin and the Cold War
Because Salk vaccine was used so extensively in the United States, Sabin
had to go overseas in the late 1950s to find people for his clinical
trials, in the Belgian Congo and, on a massive scale, in the Soviet
Union. An American was able to conduct an extensive polio vaccine trial
in the Soviet Union at the height of the cold war because the fear
of polio was stronger than political differences. |
“After getting satisfactory results of tests of your vaccine in 20,000 children we are going to prepare from your strains (1956) material for vaccination of 2ñ3 million people more, and after thorough laboratory tests of this vaccine, to use it in our country in 1959.”
—Dr. Mikhail Chumakov to Albert Sabin, letter of December 26, 1958 |
In the first five months of 1959, ten million children in the Soviet
Union received the Sabin oral vaccine. Albert Sabin received a medal
in gratitude from the Russian government during the height of the cold
war. |
Left: Albert Sabin with Dr. Victor Zhdanov, Soviet deputy
minister of health, 1958 Courtesy of Heloisa Sabin
Right: Albert Sabin's medal, box and vial of Russian oral vaccine, matchbox
advertising the vaccine campaign, two photographs of Sabin with Russian scientists,
1956-1958 Medal courtesy of University of Cincinnati, Cincinnati Medical
Heritage Center, Academic Information Technology and Libraries; other items
courtesy of Heloisa Sabin
|
Killed or Live Vaccine?
Albert Sabin and other researchers, including John Enders and Hilary Koprowski, had argued that long-term immunity to polio could only be achieved with a live though greatly weakened virus, and that it must follow the same route of infection as wild-type poliovirus—through the mouth, and infecting intestinal tissue.
Weakening the virus required passing it through a succession of animals—rats, mice, or monkeys. This allowed it to become more virulent for these hosts, and less so for humans. Hilary Koprowski carried out the first successful trial of weakened virus vaccine in February 1950. |
Rhesus monkeys in laboratory, 1956 Courtesy of March of Dimes
Medical Miracles Are Complicated
Although the scientific method of hypothesis formulation, testing, and
verification is straightforward, even the most spectacular achievements
involve complicated issues and tough choices. The scientists who raced
toward effective polio vaccines tested their work on prisoners, institutionalized
children, and tens of thousands of monkeys, as well as on themselves and
their family members. They believed they were serving the greater good
of society and of science.
• More than 100,000 monkeys were killed in the course of developing
the polio vaccines.
• One rhesus monkey, when killed, supplied sixty-five doses of vaccine. |
