First- and second-graders line up for Salk Polio vaccine shots on April 23, 1955. Regardless of where anyone stands on the matter, we know that vaccinations have been protecting us from diseases for decades. In 1921, the United States recorded 206,000 cases, which resulted in 15,520 deaths, according to the History of Vaccines website. According to the CDC, polio was once one of the most feared diseases in the U.S. Since 1979, there have been no polio cases that originated in the U.S.