"Armed with the knowledge of different virus types of the same virus group, scientists worked on vaccines against all types to prevent all disease. By 1954, after decades of well-funded research, Jonas Salk and his team developed the first killed virus vaccine. It was a vaccine against polio, and it went against the dogmas established at the time: the vaccine had to contain live/attenuated virus, and that a dead virus could not cause an immune response. The work of Isabel Morgan, MD, and other women helped lead the way to a vaccine that saved thousands of children's lives. The 1960s brought the oral polio vaccine as a replacement to Salk's vaccine, after the Cutter Incident eroded the public's trust in vaccines. The oral vaccine, developed by Albert Sabin, was tested in the Soviet Union and Latin America, and then brought to the United States with much success. By the 1990s, polio was eliminated from the United States and much of Europe. By the early 2000s, polio was eliminated from the Americas, Europe, and most of Asia. By the 2010s, polio had receded to local outbreaks in Africa and Central Asia. By the 2020s, types 2 and 3 of polio are eradicated, and type 1 is only present in Central Asia."