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