Timeline:  The Fight Against Polio

"Paralytic poliomyelitis (polio) takes its toll worldwide, affecting mostly children. The disease is known as infantile paralysis.

1894        The first known polio epidemic in the United States occurs in Vermont.

1908        Dr. Karl Landsteiner discovers that a virus causes polio.

1916        The
first major polio epidemic strikes in the United States; 27,000 people suffer paralysis and 6,000 die. 

Franklin D. Roosevelt is diagnosed with polio.

1928        Iron lungs are introduced to help patients with acute polio breathe.

1932        Franklin D. Roosevelt is elected President of the United States.

1938        President Roosevelt founds the National Foundation for Infantile Paralysis (NFIP), known today as the March of Dimes. 

Dr. Jonas Salk begins working with virologist and epidemiologist Dr. Thomas 
                 Francis Jr. on an influenza vaccine later used by the US military during World War II.

1947        The University of Pittsburgh recruits Dr. Jonas Salk to develop a virus research program. Techniques Salk picked up while
                      working with influenza are later used to develop the polio vaccine.

1948-49  Scientists confirm the existence of three strains of poliovirus.

1949        Dr. John Enders, Dr. Frederick Robbins and Dr. Thomas Weller develop a way to grow poliovirus in tissue culture,
                      a breakthrough that aided the creation of the polio vaccine. Their work earned them the Nobel Prize
                      in physiology or medicine in 1954.

1952        The United States reports 57,628 polio cases -- the worst US epidemic on record.

                 Dr. Salk and his colleagues develop a potentially safe, injectable vaccine against polio. Nearly 15,000
                        Pittsburgh-area subjects, mostly children, receive the vaccine in pilot trials.

                 Salk's former mentor, Dr. Thomas Francis, designs, directs and evaluates field trials of the polio vaccine.
                          Unprecedented in their scope and size, the trials involve around 1.8 million children from the United States,
                          Canada and Finland. They are among the first to use the double-blind process that has since become standard.

1955        On April 12, Dr. Francis announces the results of the field trials, declaring that Salk's vaccine is "safe, effective and potent."

1955-57  Once the vaccine becomes available, US polio cases drop by 85-90 percent.

1961        Dr. Albert Sabin develops an oral polio vaccine.

1963        Congress creates the Immunization Grant Program.  Reported US polio cases plummet to just 396.

1979        The last US case of polio caused by wild poliovirus is reported.

1985        Rotary International establishes its PolioPlus program.  Rotary has contributed more than $500 million to
                        fight polio worldwide.

1988        Worldwide, polio continues to affect some 350,000 people in 125 countries. In response, the
                           World Health Organization, UNICEF, Rotary International and the US Centers for Disease Control
                           and Prevention launch the Global Polio Eradication Initiative.

1994        The Americas are certified polio-free.

1999        The US Public Health Service recommends that the oral vaccine be discontinued in the United States and a modified injectable
                      vaccine becomes the preferred vaccine. The oral vaccine -- which is cheaper and easier to administer -- remains the vaccine
                      of choice for eradication efforts elsewhere around the globe.

2000         The Western Pacific region is certified polio-free.

2002         Europe is certified polio-free.

2005         April 12  marks the 50th anniversary of the Salk vaccine.  Global eradication efforts have helped lower worldwide
                          polio cases to just 1,263 reported cases in 2004."

Source:  Salk Polio Vaccine Conquered Terrifying Disease by Joe Palca