Jonas Salk

Poliomyelitis (shortened to polio) has been around for thousands of

years, and there is still no cure, but at the peak of its devastation in the United

States, Dr. Jonas Salk introduced a way to prevent it. Polio attacks the nerve

cells and sometimes the central nervous system, causing muscle wasting,

paralysis, and even death. The disease, whose symptoms are flu like, stuck

mostly children, and in the first half of the 20th century the epidemics of polio

were becoming more devastating. Salk, while working at the Virus Research

Lab at the University of Pittsburgh, developed a polio vaccine, and the

medical trials to prove its effectiveness and safety are still being analyzed.

Fifty years ago the largest medical experiment in history took place to

test Salk's poliomyelitis vaccine. Close to two million children across the

United States and Canada were involved in the trial, which was administered

by the National Foundation for Infantile Paralysis (NFIP), also known as the

March of Dimes. The foundation, created in 1938 by President Franklin D.

Roosevelt (a polio victim) and his law partner Basil O'Connor. Across the

United States, 623,972 school children were injected with the vaccine or a

placebo, using a double blind technique in which neither recipient nor

administrator knew which one there were getting. The results, announced in

1955, showed good statistical evidence that Jonas Salk's "killed virus"

preparation was 80-90% effective in preventing paralytic poliomyelitis.

The statistical design used in the experiment was singular, prompting

criticism. Eighty four test areas in eleven states used a textbook model: in a

randomized, blinded design all participating children in the first three grades

of school (ages 6-9) received injections of either vaccine for placebo and

were observed. At the same time though, 127 test areas in 33 states used an

"observed control" design: where the participating children in the second

grade received injections of vaccine, no placebo was given, and children in all

three grades were then observed for the duration of the polio season. The use

of the dual protocol illustrates both the power and the limitations of

randomized clinical trials. The control trials with the placebo were important

to define the vaccine as the product of scientific medicine, while the observed

trials